Prevention of preeclampsia with low-dose aspirin in healthy, nulliparous pregnant women. The National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units

Impact of low-dose aspirin exposure on obstetrical outcomes: a meta-analysis

OBJECTIVE

To assess the impact of low-dose aspirin (LDA) on obstetrical outcomes through a meta-analysis of placebo-controlled randomized controlled trials (RCTs).

METHODS

A systematic search of the PubMed, Cochrane Library, Web of Science and Embase databases from inception to January 2024 was conducted to identify studies exploring the role of aspirin on pregnancy, reporting obstetrical-related outcomes, including preterm birth (PTB, gestational age <37 weeks), small for gestational age (SGA), low birth weight (LBW, birthweight < 2500g), perinatal death (PND), admission to the neonatal intensive care unit (NICU), 5-min Apgar score < 7 and placental abruption. Relative risks (RRs) were estimated for the combined outcomes. Subgroup analyses were performed by risk for preeclampsia (PE), LDA dosage (<100 mg vs. ≥100 mg) and timing of onset (≤20 weeks vs. >20 weeks).

RESULTS

Forty-seven studies involving 59,124 participants were included. Compared with placebo, LDA had a more significant effect on low-risk events such as SGA, PTB and LBW. Specifically, LDA significantly reduced the risk of SGA (RR = 0.91, 95% CI: 0.87-0.95), PTB (RR = 0.93, 95% CI: 0.89-0.97) and LBW (RR = 0.94, 95% CI: 0.89-0.99). For high-risk events, LDA significantly lowered the risk of NICU admission (RR = 0.93, 95% CI: 0.87-0.99). On the other hand, LDA can significantly increase the risk of placental abruption (RR = 1.72, 95% CI: 1.23-2.43). Subgroup analyses showed that LDA significantly reduced the risk of SGA (RR = 0.86, 95% CI: 0.77-0.97), PTB (RR = 0.93, 95% CI: 0.88-0.98) and PND (RR = 0.65, 95% CI: 0.48-0.88) in pregnant women at high risk of PE, whereas in healthy pregnant women LDA did not significantly improve obstetrical outcomes, but instead significantly increased the risk of placental abruption (RR = 5.56, 95% CI: 1.92-16.11). In pregnant women at high risk of PE, LDA administered at doses ≥100 mg significantly reduced the risk of SGA (RR = 0.77, 95% CI: 0.66-0.91) and PTB (RR = 0.56, 95% CI: 0.32-0.97), but did not have a statistically significant effect on reducing the risk of NICU, PND and LBW. LDA started at ≤20 weeks significantly reduced the risk of SGA (RR = 0.76, 95% CI: 0.65-0.89) and PTB (RR = 0.56, 95% CI: 0.32-0.97).

CONCLUSIONS

To sum up, LDA significantly improved neonatal outcomes in pregnant women at high risk of PE without elevating the risk of placental abruption. These findings support LDA's clinical application in pregnant women, although further research is needed to refine dosage and timing recommendations.

Aspirin resistance in pregnancy is associated with reduced interleukin-2 (IL-2) concentrations in maternal serum: Implications for aspirin prophylaxis for preeclampsia

OBJECTIVES

To evaluate the impact of aspirin resistance on the incidence of preeclampsia and maternal serum biomarker levels in pregnant individuals at high-risk of preeclampsia receiving low dose aspirin (LDA).

STUDY DESIGN

We performed a secondary analysis of a randomized, placebo-controlled trial of LDA (60 mg daily) for preeclampsia prevention in high-risk individuals (N = 524) on pregnancy outcomes and concentrations of PLGF, IL-2, IL-6, thromboxane B2 (TXB2), sTNF-R1 and sTNF-R2 from maternal serum.

MAIN OUTCOME MEASURES

LDA-resistant individuals were defined as those having a TXB2 concentration >10 ng/ml or <75 % reduction in concentration at 24-28 weeks after LDA administration. Comparisons of outcomes were performed using a Fisher's Exact Test. Mean concentrations of maternal serum biomarkers were compared using a Student's t-test. Pearson correlation was calculated for all pairwise biomarkers. Longitudinal analysis across gestation was performed using linear mixed-effects models accounting for repeated measures and including BMI and maternal age as covariates.

RESULTS

We classified 60/271 (22.1 %) individuals as LDA-resistant, 179/271 (66.1 %) as LDA-sensitive, and 32/271 (11.8 %) as non-adherent. The prevalence of preeclampsia was not significantly different between the LDA and placebo groups (OR = 1.43 (0.99-2.28), p-value = 0.12) nor between LDA-sensitive and LDA-resistant individuals (OR = 1.27 (0.61-2.8), p-value = 0.60). Mean maternal serum IL-2 concentrations were significantly lower in LDA-resistant individuals relative to LDA-sensitive individuals (FDR < 0.05).

CONCLUSIONS

These results suggest a potential role for IL-2 in the development of preeclampsia modulated by an individuals' response to aspirin, presenting an opportunity to optimize aspirin prophylaxis on an individual level to reduce the incidence of preeclampsia.

Preeclampsia epidemiology(ies) and pathophysiology(ies)

Preeclampsia/eclampsia was first described 2000 years ago. Concepts guiding diagnosis have changed over time making longitudinal studies challenging. Similarly, concepts of pathophysiology have evolved from eclampsia as a pregnancy seizure disorder to preeclampsia as a hypertensive and renal disorder to our current concept of a preeclampsia as a pregnancy specific, multisystemic inflammatory disorder. Although preeclampsia is pregnancy specific and many pathophysiologic findings begin to resolve with delivery, its impact extends beyond pregnancy. The risk of cardiovascular and neurological disease is increased after pregnancy in women who have had preeclampsia. The disorder is not a disease, but a syndrome and emerging data indicate multiple pathways to the syndrome. It is likely that our failure to have a major impact on prediction and prevention despite a large increase in understanding is due to the existence of multiple subtypes of preeclampsia. This concept should guide future research.

Task force of the Brazilian Society of Otology - evaluation and management of peripheral facial palsy

OBJECTIVE

To review key evidence-based recommendations for the diagnosis and treatment of peripheral facial palsy in children and adults.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on peripheral facial palsy were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 main parts: (1) Evaluation and diagnosis of facial palsy: electrophysiologic tests, idiopathic facial palsy, Ramsay Hunt syndrome, traumatic peripheral facial palsy, recurrent peripheral facial palsy, facial nerve tumors, and peripheral facial palsy in children; and (2) Rehabilitation procedures: surgical decompression of the facial nerve, facial nerve grafting, surgical treatment of long-term peripheral facial palsy, and non-surgical rehabilitation of the facial nerve.

CONCLUSIONS

Peripheral facial palsy is a condition of diverse etiology. Treatment should be individualized according to the cause of facial nerve dysfunction, but the literature presents better evidence-based recommendations for systemic corticosteroid therapy.

The effects of low-dose aspirin on preterm birth: a systematic review and meta-analysis of randomized controlled trials

AIM

To conduct a systematic review and meta-analysis of all randomized controlled trials (RCTs) that evaluated the efficacy of low-dose aspirin (LDA, ≤ 160 mg/day) on preventing preterm birth (PB).

METHODS

Five databases were screened from inception until June 25, 2023. The RCTs were assessed for quality according to Cochrane's risk of bias tool. The endpoints were summarized as risk ratio (RR) with 95% confidence interval (CI).

RESULTS

Overall, 40 RCTs were analyzed. LDA significantly decreased the risk of PB < 37 weeks (RR: 0.91, 95% CI 0.87, 0.96, p < 0.001, moderate certainty of evidence) with low between-study heterogeneity (I2 = 23.2%, p = 0.11), and PB < 34 weeks (RR: 0.78, 95% CI 0.61, 0.99, p = 0.04, low certainty of evidence) with high between-study heterogeneity (I2 = 58.3%, p = 0.01). There were no significant differences between both groups regarding the risk of spontaneous (RR: 0.94, 95% CI 0.83, 1.07, p = 0.37) and medically indicated (RR: 1.28, 95% CI 0.87, 1.88, p = 0.21) BP < 37 weeks. Sensitivity analysis revealed robustness for all outcomes, except for the risk of PB < 34 weeks. For PB < 37 weeks and PB < 34 weeks, publication bias was detected based on visual inspection of funnel plots for asymmetry and statistical significance for Egger's test (p = 0.009 and p = 0.0012, respectively).

CONCLUSION

LDA can significantly reduce the risk of PB < 37 and < 34 weeks. Nevertheless, further high-quality RCTs conducted in diverse populations, while accounting for potential confounding factors, are imperative to elucidate the optimal aspirin dosage, timing of initiation, and treatment duration for preventing preterm birth and to arrive at definitive conclusions.

Analysis of risk factors of preeclampsia in pregnant women with chronic hypertension and its impact on pregnancy outcomes

OBJECTIVE

To investigate the risk factors and maternal and fetal outcomes of preeclampsia after pregnancy in patients with primary chronic hypertension.

METHODS

A total of 500 singleton pregnant women with a history of hypertension who were admitted for delivery at our Hospital from March 2015 to May 2022 were retrospectively collected by random sampling and divided into the non-occurrence group (n = 200) and the occurrence group (n = 300) according to whether they were complicated by preeclampsia. Afterward, the general data and the pregnancy-related data of patients were collected for comparison.

RESULTS

The univariate analysis showed significant differences between the non-occurrence group and the occurrence group in terms of the proportion of preeclampsia history (4.00% VS 24.67%, χ2 = 37.383, P < 0.001), duration of hypertension > 3 years (18.00% VS 31.67%, χ2 = 11.592, P < 0.001), systemic therapy (20.50% VS 10.00%, χ2 = 10.859, P < 0.001), gestational age at admission [37.72 (34.10, 38.71) VS 35.01 (31.91, 37.42) weeks, Z = -9.825, P < 0.001]. Meanwhile, the multivariate analysis showed that a history of preeclampsia (OR = 6.796, 95% CI: 3.575 ∼ 10.134, χ2 = 8.234, P < 0.001), duration of hypertension > 3 years (OR = 3.456, 95% CI: 2.157 ∼ 5.161, χ2 = 9.348, P < 0.001), and a lack of systemic antihypertensive treatment (OR = 8.983, 95% CI: 7.735 ∼ 9.933, χ2 = 9.123, P < 0.001) were risk factors for chronic hypertension complicated by preeclampsia during pregnancy.

CONCLUSION

A history of preeclampsia, a longer duration of hypertension, and a lack of systematic antihypertensive treatment are risk factors for chronic hypertension complicated by preeclampsia during pregnancy. The occurrence of preeclampsia in pregnant women with chronic hypertension increases the incidence of maternal HELLP syndrome and fetal distress.

Low-dose aspirin for the prevention of preterm birth in nulliparous women: systematic review and meta-analysis

OBJECTIVE

The objective was to assess the efficacy and safety of low-dose aspirin for the prevention of preterm birth in nulliparous women.

DATA SOURCES

We searched PubMed, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to June 2022.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that compared aspirin to placebo in nulliparous women were eligible.

METHODS

This study was reported in accordance with the PRISMA 2020 checklist. The primary outcomes of this study were the rates of preterm birth at less than 37 weeks and less than 34 weeks of gestation. The secondary outcomes included postpartum hemorrhage, placental abruption, cesarean section, any hypertensive disorder of pregnancy and small for gestational age. Relative risks with their 95% confidence intervals were calculated for analysis. Heterogeneity was assessed by Cochran's Q test and Higgins's I2. A random-effects model was used when I2 was > 50% to generate the RR and 95% CI; otherwise, a fixed-effects model was used. The risk of publication bias was assessed by funnel plots. We performed sensitivity analysis by sequentially omitting each included study to confirm the robustness of the analysis.

RESULTS

Seven studies with a total of 29,029 participants were included in this review. Six studies were assessed as having a low risk of bias or an unclear risk of bias, and one study was judged as having a high risk of bias. In nulliparous women, low-dose aspirin was associated with a significant reduction in the rate of preterm birth at less than 34 weeks of gestational age (RR 0.84,95% CI: 0.71-0.99; I2 = 0%; P = 0.04), but we did not observe a significant difference in the rate of preterm birth at less than 37 weeks of gestation (RR 0.96,95% CI: 0.90-1.02; I2 = 31%; P = 0.18). Low-dose aspirin was associated with a significant increase in the rates of postpartum hemorrhage (RR 1.32,95% CI: 1.14-1.54; I2 = 0%; P = 0.0003), placental abruption (RR 2.18,95% CI: 1.10-4.32; I2 = 16%; P = 0.02) and cesarean section (RR 1.053, 95% CI: 1.001-1.108; I2 = 0%; P = 0.05) in nulliparous women. We also did not observe a significant effect of low-dose aspirin on the rates of any hypertensive disorder of pregnancy (RR 1.05, 95% CI: 0.96-1.14; I2 = 9%; P = 0.28) or small for gestational age (RR 0.96, 95% CI: 0.91-1.02; I2 = 0%; P = 0.16) in nulliparous women. Funnel plots indicated that no significant publication bias existed in this meta-analysis. Except for preterm birth at less than 34 weeks of gestation, placental abruption and cesarean section, the sensitivity analysis showed similar results, which confirmed the robustness of this meta-analysis.

CONCLUSIONS

Low-dose aspirin might reduce the risk of preterm birth at less than 34 weeks of gestation in nulliparous women. The use of low-dose aspirin in nulliparous women increased the risk of postpartum hemorrhage and might increase the risk of placental abruption and cesarean section.

Potential impact on using aspirin as the primary prevention of adverse pregnancy outcomes in twins conceived using ART

With the development of assisted reproductive technology, the number of twin pregnancies is increasing year by year. Given the increased risk of pregnancy complications associated with twin pregnancies, and the fact that these babies are rare and difficult to obtain through assisted reproductive technology, clinicians urgently require finding effective and safe drugs to improve pregnancy outcomes. Low-dose aspirin can not only promote placental blood supply, but also effectively anti-inflammatory. Whether Low-dose aspirin can effectively reduce the risk of pregnancy complications in this special group needs to be clarified. We therefore retrospectively analyzed 665 twin pregnancies from assisted reproduction technology, grouped according to aspirin use, and followed pregnancy outcomes to assess bleeding risk. Low-dose aspirin was found to be effective in preventing preeclampsia without a significant risk of bleeding. However, aspirin does not prevent specific complication in twin pregnancies and seems to have a better preventive effect only when the mother is under 30, which should alarm clinicians should not blindly using aspirin in this particular group.

[Preeclampsia: Guidelines for clinical practice from the French College of Obstetricians and Gynecologists]

OBJECTIVE

To identify strategies to reduce maternal and neonatal morbidity related to preeclampsia.

MATERIAL AND METHODS

The quality of evidence of the literature was assessed following the GRADE® method with questions formulated in the PICO format (Patients, Intervention, Comparison, Outcome) and outcomes defined a priori and classified according to their importance. An extensive bibliographic search was performed on PubMed, Cochrane, EMBASE and Google Scholar databases. The quality of the evidence was assessed (high, moderate, low, very low) and recommendations were formulated as a (i) strong, (ii) weak or (iii) no recommendation. The recommendations were reviewed in two rounds with external reviewers (Delphi survey) to select the consensus recommendations.

RESULTS

Preeclampsia is defined by the association of gestational hypertension (systolic blood pressure≥140mmHg and/or diastolic blood pressure≥90mmHg) and proteinuria≥0.3g/24h or a Proteinuria/Creatininuria ratio≥30mg/mmol occurring after 20 weeks of gestation. Data from the literature do not show any benefit in terms of maternal or perinatal health from implementing a broader definition of preeclampsia. Of the 31 questions, there was agreement between the working group and the external reviewers on 31 (100%). In general population, physical activity during pregnancy should be encouraged to reduce the risk of preeclampsia (Strong recommendation, Quality of the evidence low) but an early screening based on algorithms (Weak recommendation, Quality of the evidence low) or aspirin administration (Weak recommendation, Quality of the evidence very low) is not recommended to reduce maternal and neonatal morbidity related to preeclampsia. In women with preexisting diabetes or hypertension or renal disease, or multiple pregnancy, the level of evidence is insufficient to determine whether aspirin administration during pregnancy is useful to reduce maternal and perinatal morbidity (No recommendation, Quality of the evidence low). In women with a history of vasculo-placental disease, low dose of aspirin (Strong recommendation, Quality of the evidence moderate) at a dosage of 100-160mg per day (Weak recommendation, Quality of the evidence low), ideally before 16 weeks of gestation and not after 20 weeks of gestation (Strong recommendation, Quality of the evidence low) until 36 weeks of gestation (Weak recommendation, Quality of the evidence very low) is recommended. In a high-risk population, additional administration of low molecular weight heparin is not recommended (Weak recommendation, Quality of the evidence moderate). In case of preeclampsia (Weak recommendation, Quality of the evidence low) or suspicion of preeclampsia (Weak recommendation, Quality of the evidence moderate, the assessment of PlGF concentration or sFLT-1/PlGF ratio is not routinely recommended) in the only goal to reduce maternal or perinatal morbidity. In women with non-severe preeclampsia antihypertensive agent should be administered orally when the systolic blood pressure is measured between 140 and 159mmHg or diastolic blood pressure is measured between 90 and 109mmHg (Weak recommendation, Quality of the evidence low). In women with non-severe preeclampsia, delivery between 34 and 36+6 weeks of gestation reduces severe maternal hypertension but increases the incidence of moderate prematurity. Taking into account the benefit/risk balance for the mother and the child, it is recommended not to systematically induce birth in women with non-severe preeclampsia between 34 and 36+6 weeks of gestation (Strong recommendation, Quality of evidence high). In women with non-severe preeclampsia diagnosed between 37+0 and 41 weeks of gestation, it is recommended to induce birth to reduce maternal morbidity (Strong recommendation, Low quality of evidence), and to perform a trial of labor in the absence of contraindication (Strong recommendation, Very low quality of evidence). In women with a history of preeclampsia, screening maternal thrombophilia is not recommended (Strong recommendation, Quality of the evidence moderate). Because women with a history of a preeclampsia have an increased lifelong risk of chronic hypertension and cardiovascular complications, they should be informed of the need for medical follow-up to monitor blood pressure and to manage other possible cardiovascular risk factors (Strong recommendation, Quality of the evidence moderate).

CONCLUSION

The purpose of these recommendations was to reassess the definition of preeclampsia, and to determine the strategies to reduce maternal and perinatal morbidity related to preeclampsia, during pregnancy but also after childbirth. They aim to help health professionals in their daily clinical practice to inform or care for patients who have had or have preeclampsia. Synthetic information documents are also offered for professionals and patients.

Maternal-neonatal events resulting from medications for preventing hypertensive disorders in high-risk pregnant women: A systematic review and network meta-analysis

BACKGROUND

There have been few studies reporting on maternal and neonatal events in high-risk pregnant women receiving medications for preventing hypertensive disorders of pregnancy (HDP).

OBJECTIVE

To identify placental abruption, postpartum hemorrhage, neonatal intraventricular hemorrhage, and neonates with small for gestational age (SGA) or growth restriction resulting from medications for preventing HDP in high-risk pregnant women using a network meta-analysis.

SEARCH STRATEGY

All randomized controlled trials comparing the most commonly used medications (antiplatelet agents, anticoagulants, antioxidants, nitric oxide, and calcium) for preventing HDP in high-risk pregnant women were searched from the Cochrane Pregnancy and Childbirth's Specialized Register of Controlled Trials until July 31, 2020, without language restriction.

SELECTION CRITERIA

Two of the authors independently selected the eligible trials.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data and assessed the methodological quality of the included trials. Pairwise and network meta-analyses were used to determine comparative risk ratios and 95% confidence intervals.

MAIN RESULTS

The 51 included trials involved 69 669 pregnant women. Compared with placebo/no treatment, antioxidants slightly reduced placental abruption with high-certainty evidence. Antiplatelet agents probably reduced SGA with low-certainty evidence and slightly increased neonatal intraventricular hemorrhage with moderate-certainty evidence.

CONCLUSION

Antiplatelet agents probably reduce SGA, but neonatal intraventricular hemorrhage should be monitored.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42018096276.

Low-dose aspirin and racial disparities in spontaneous preterm delivery in low-risk individuals

BACKGROUND

Preterm birth is a leading cause of perinatal morbidity and mortality. There are significant racial disparities in the rates of preterm delivery in the United States, with Black individuals at disproportionately higher risk than their White counterparts. Although low-dose aspirin is currently under investigation for reducing the rates of preterm delivery, limited data are available on how the use of low-dose aspirin might affect racial and ethnic disparities in the rates of preterm delivery.

OBJECTIVE

Our group and others have shown that low-dose aspirin decreases spontaneous preterm delivery in low-risk parturients. This study aimed to examine whether the relationship between low-dose aspirin and the risk of spontaneous preterm delivery is modified by race and ethnicity.

STUDY DESIGN

This was a secondary analysis of a randomized clinical trial examining low-dose aspirin for preeclampsia prevention in low-risk nulliparous individuals. The parent trial defined low risk as the absence of preexisting hypertension or other medical comorbidities. Participants received 60-mg aspirin or placebo between 13 and 25 weeks of gestation. Here, multiple pregnancies, fetal anomalies, terminations or abortions at <20 weeks of gestation, and participants with previous miscarriages were excluded. Our exposure, race and ethnicity, was self-reported in the parent trial and categorized as non-Hispanic White, Hispanic, non-Hispanic Black, and other. The primary outcome was spontaneous preterm delivery at <34 weeks of gestation; the secondary outcomes included spontaneous preterm delivery at <37 weeks of gestation and all preterm deliveries at <34 and <37 weeks of gestation. Fit logistic regression models were used to examine how the use of low-dose aspirin modified the relationship between race and ethnicity and preterm delivery, adjusting for confounders. Furthermore, sensitivity analyses were performed to compare the rates of preterm delivery by race and ethnicity.

RESULTS

Of note, 2528 of 3171 parent study participants were included in this analysis. Of the participants, 425 (16.8%) were White, 819 (32.4%) were Hispanic, 1265 (50%) were Black, and 19 (0.8%) were other. The baseline characteristics differed among racial and ethnic groups, including maternal age, body mass index, education level, marital status, tobacco and alcohol use, and pregnancy loss. The rate of spontaneous preterm delivery at <34 weeks of gestation was significantly higher in Black participants (2.8%) than in White (1.2%) and Hispanic (1.2%) participants (P=.04). Logistical regression analysis showed that Black race was no longer an independent risk factor for spontaneous preterm delivery at <34 weeks of gestation when controlling for low-dose aspirin (adjusted odds ratio, 1.71; 95% confidence interval, 0.67-4.40). A similar pattern was found for spontaneous preterm delivery at <37 weeks of gestation and preterm delivery at <34 and <37 weeks of gestation. In our sensitivity analyses, spontaneous preterm delivery at <34 weeks of gestation differed by race and ethnicity in the placebo group (P=.01) but did not differ in the low-dose aspirin group (P=.90).

CONCLUSION

The use of low-dose aspirin mitigated racial disparities in spontaneous preterm delivery at <34 weeks of gestation. Additional investigation is warranted to assess the reproducibility of our findings.

Low-dose aspirin therapy for the prevention of preeclampsia: time to reconsider our recommendations?

The American College of Obstetricians and Gynecologists recommends initiation of 81 mg of aspirin daily for women at risk of preeclampsia between 12 and 28 weeks' gestation, optimally before 16 weeks, with continuation until delivery. The World Health Organization recommends that 75 mg of aspirin should be initiated before 20 weeks of gestation for women at high risk of preeclampsia. Both the Royal College of Obstetricians and Gynaecologists and the National Institute of Health and Care Excellence quality statement on "Antenatal Assessment of Pre-eclampsia Risk" request that healthcare providers prescribe low-dose aspirin to pregnant women at increased risk of preeclampsia daily from 12 weeks of gestation. The Royal College of Obstetricians and Gynaecologists recommends 150 mg of aspirin daily, and the National Institute of Health and Care Excellence guidelines suggest risk stratification with a dosage of 75 mg for those at moderate risk of preeclampsia and 150 mg for those at high risk of preeclampsia. The International Federation of Gynecology and Obstetrics initiative on preeclampsia recommends 150 mg of aspirin to be initiated at 11 to 14+6 week's gestation and also proposes that 2 tablets of 81 mg is an acceptable alternative. Review of the available evidence suggests that both the dosage and timing of aspirin initiation is key to its effectiveness at reducing the risk of preeclampsia. Doses of >100 mg of aspirin daily initiated before 16 weeks' gestation seem to be most effective at reducing the risk of preeclampsia and thus dosages recommended by most major societies and organizations may not be effective. Randomized control trials examining 81 mg vs 162 mg of aspirin daily for the prevention of preeclampsia are required to assess the safety and efficacy of aspirin dosages available in the United States.

The Role of Acetylsalicylic Acid in the Prevention of Pre-Eclampsia, Fetal Growth Restriction, and Preterm Birth

BACKGROUND

Recent studies suggest that low-dose acetylsalicylic acid (ASA) can lower pregnancy-associated morbidity.

METHODS

This review is based on pertinent publications that were retrieved by a selective search in PubMed, with special attention to systematic reviews, metaanalyses, and randomized controlled trials.

RESULTS

Current meta-analyses document a reduction of the risk of the occurrence of pre-eclampsia (RR 0.85, NNT 50), as well as beneficial effects on the rates of preterm birth (RR 0.80, NNT 37), fetal growth restriction (RR 0.82, NNT 77), and perinatal death (RR 0.79, NNT 167). Moreover, there is evidence that ASA raises the rate of live births after a prior spontaneous abortion, while also lowering the rate of spontaneous preterm births (RR 0.89, NNT 67). The prerequisites for therapeutic success are an adequate ASA dose, early initiation of ASA, and the identification of women at risk of pregnancy-associated morbidity. Side effects of treatment with ASA in this patient group are rare and mainly involve bleeding in connection with the pregnancy (RR 0.87, NNH 200).

CONCLUSION

ASA use during pregnancy has benefits beyond reducing the risk of pre-eclampsia. The indications for taking ASA during pregnancy may be extended at some point in the future; at present, in view of the available evidence, it is still restricted to high-risk pregnancies.

Stroke Around Pregnancy; Protection and Prevention!

As per recent studies, incidence of stroke is increasing in pregnant women. It is essential to be vigilant and well-versed in managing stroke in pregnancy, as both the mother and the baby are prone to stroke-related injury. In this viewpoint article, we have reviewed the current data from research publications on the incidence, prevalence, risk factors, and clinical presentation of stroke in pregnancy. Finally, we have discussed the plan of investigations and the current treatment guidelines for stroke in pregnancy.

MiR-141-3p promotes hypoxia-induced autophagy in human placental trophoblast cells

Preeclampsia (PE) is a pregnancy-specific disorder and a significant contributor to maternal, fetal and neonatal morbidity and mortality worldwide. Its pathogenesis is generally accepted as insufficient trophoblast invasion of the maternal endometrium and inadequate remodeling of the maternal spiral arteries. These impairments lead to elevated levels of hypoxia and oxidative stress. Autophagy has become a highly researched field in obstetrics, and this process may be essential for preimplantation development beyond the four- and eight-cell stages, and for blastocyst survival, extra-villous trophoblast functions, invasion and vascular remodeling. Several studies have shown that autophagy activation, shown by an increase in autophagy vacuoles or microtubule-associated protein 1 A/1B-light chain 3 (LC3) dots, was more common in PE than in normal pregnancy. Thus, changes in autophagic status are seen in preeclamptic placentas. MicroRNA-141-3p (miR-141-3p), a multifunctional miRNA, is involved in a variety of physiological and pathological processes, including PE and autophagy. However, the influence of miR-141-3p on autophagy regulation in trophoblast cells has yet to be described. Therefore, the objective of our study was to investigate the role of miR-141-3p in autophagy induced by hypoxia in human placental trophoblast cells. Our results found that hypoxia induced autophagy in trophoblast cells and dramatically elevated the expression of miR-141-3p. Overexpression of miR-141-3p improved autophagic activity, whereas low expression of miR-141-3p inhibited autophagic activity. Therefore, our data demonstrated that miR-141-3p promoted hypoxia-induced autophagy in placental trophoblast cells, which may be related to the development of preeclampsia.

Aspirin and Pravastatin for Preeclampsia Prevention in High-Risk Pregnancy

Preeclampsia is a hypertensive disorder of pregnancy affecting up to 8% of pregnancies. It is associated with significant neonatal and maternal morbidities and mortality. Although its pathogenesis is not completely understood, abnormal placentation resulting in imbalance in angiogenic factors, increased inflammation, and endothelial dysfunction are thought to be key pathways in the development of the disease. Administration of low-dose aspirin is recommended by professional societies for the prevention of preeclampsia in high-risk individuals. In this review, we summarize the evidence behind the use of low-dose aspirin and pravastatin in pregnant individuals at high risk of preeclampsia.

Aspirin 75 mg to prevent preeclampsia in high-risk pregnancies: a retrospective real-world study in China

BACKGROUND

Several randomized clinical trials showed that aspirin could decrease the incidence of preeclampsia (PE) in women at high risk, but data from sources other than traditional clinical trials that investigating the preventive effect of aspirin 75 mg on PE is still lacking, especially in mainland China. We aimed to use Chinese real-world data to estimate the preventive effect of low-dose aspirin (LDA) on PE.

METHODS

Clinical data of pregnant women who were at high risk of PE and had their first prenatal visit at the affiliated Taicang People's Hospital of Soochow University during November 31, 2018 and May 10, 2021 was retrospectively analyzed. Among the 266 included pregnant women, 115 individuals treated with aspirin 75 mg per day and the other 151 without such treatment were considered as the LDA group and the control group, respectively.

RESULTS

In the LDA group, 64 (55.65%) of 115 pregnant women took aspirin before 16 weeks of gestation. Besides, 12 (10.43%) and 34 (22.52%) women developed PE in the LDA group and control group, respectively; the aspirin prophylaxis was associated with a lower risk of PE (odds ratio = 0.40, 95% confidence interval = 0.20-0.82, P = 0.0098). In addition, LDA is slightly more effective when initiated before 16 weeks of gestation or in those without chronic hypertension, when compared with their counterparts.

CONCLUSION

Prophylaxis with 75 mg per day of aspirin in high-risk women resulted in a significantly lower incidence of PE than that in the control group.

Aspirin for prevention of preeclampsia and adverse perinatal outcome in twin pregnancies: a systematic review and meta-analysis

OBJECTIVE

This study aimed to investigate the potential role of aspirin in reducing the risk of preeclampsia and adverse maternal and perinatal outcomes in twin pregnancies.

DATA SOURCES

Medline, Embase, Google Scholar, Cochrane, and ClinicalTrial.gov databases were searched.

STUDY ELIGIBILITY CRITERIA

The search and selection criteria were restricted to the English language.

METHODS

The primary outcome was the incidence of preeclampsia. The secondary outcomes included gestational hypertension; fetal growth restriction; preterm birth, either spontaneous or iatrogenic, before 34 weeks of gestation; gestational age at birth; neonatal birthweight; and adverse events secondary to the administration of aspirin, including antepartum and postpartum hemorrhage. In addition, subgroup analyses according to chorionicity (dichorionic vs monochorionic), aspirin dose, and gestational age at administration of aspirin (<16 vs ≥16 weeks of gestation) and considering only studies with a daily aspirin dose of ≥100 mg/d were performed. Head-to-head meta-analyses reporting results as summary odds ratios and mean differences were used to analyze categorical and continuous variables, respectively. Quality assessment for randomized controlled trials was independently performed by 2 researchers based on the risk of bias that was assessed using the revised Cochrane risk-of-bias tool for randomized trials. The conclusion of the meta-analysis on the primary outcome was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation.

RESULTS

Overall, 9 studies (2273 twin pregnancies) were included. When considering all studies, the risk of preeclampsia was lower in twin pregnancies treated with aspirin than in those not treated with aspirin (odds ratio, 0.64; 95% confidence interval, 0.48-0.85; P=.003), although there was no significant difference in the risk of gestational hypertension (P=.987), fetal growth restriction (P=.9), or adverse maternal and perinatal events (P=.9) in twin pregnancies treated with aspirin compared with those not treated with aspirin. There was no significant difference in the gestational age at birth (P=.2) and neonatal birthweight (P=.06) between women receiving aspirin and those not receiving aspirin. When considering only studies with an aspirin dose of >100 mg/d, the risk of preeclampsia (odds ratio, 0.45; 95% confidence interval, 0.23-0.86; P=.02) was significantly lower in pregnancies receiving aspirin than in those not receiving aspirin, Conversely, there was no significant difference in the risk of gestational hypertension (P=.20), fetal growth restriction (P=.1), gestational age at birth (P=.06), and neonatal weight (P=.05) between the 2 groups. Furthermore, there was no significant difference in the risk of preeclampsia when considering only studies with an aspirin dose of >80 mg/d (P=.611). The association between the administration of aspirin and preeclampsia persisted when considering an aspirin dose of >100 mg/day or when the medication was started before 16 weeks of gestation. The overall quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation assessment was low.

CONCLUSION

The administration of aspirin in women with twin pregnancies reduced the risk of preeclampsia. The findings from this study highlighted the need for randomized controlled trials elucidating the actual role of aspirin in affecting maternal and perinatal outcomes in twin pregnancies.

Aspirin use during pregnancy may be a potential risk for postpartum hemorrhage and increased blood loss: a systematic review and meta-analysis

OBJECTIVE

The association between aspirin use during pregnancy and the risk of postpartum hemorrhage remains unclear. This study aimed to explore the incidence of postpartum hemorrhage and the amount of postpartum blood loss among women who used aspirin during pregnancy.

DATA SOURCES

From inception to October 2022, this study searched the following databases: MEDLINE, Web of Science, Embase, and the Cochrane Central Register of Controlled Trials.

STUDY ELIGIBILITY CRITERIA

Studies comparing pregnancy outcomes that covered the incidence of postpartum hemorrhage or the amount of postpartum blood loss in pregnancies with aspirin vs placebo (or no aspirin) were included.

METHODS

Reviewers separately ascertained studies, obtained data, and gauged study quality. The meta-analysis was conducted using a random effects model owing to the probable heterogeneity of the included studies. The rates of postpartum hemorrhage or the mean amounts of postpartum blood loss were compared, and the odds ratios or mean differences with 95% confidence intervals were estimated. Of note, 2 parts performed both a pooled analysis of randomized controlled trials and cohort studies and a separate analysis of randomized controlled trials.

RESULTS

Overall, 21 studies with 373,926 women were included in the postpartum hemorrhage part, and 7 studies with 10,163 women were included in the postpartum blood loss part. The results suggested that aspirin use during pregnancy was associated with an increased incidence of postpartum hemorrhage (odds ratio, 1.20; 95% confidence interval, 1.07-1.34). When only randomized controlled trials were retained, the results remained significant (odds ratio, 1.12; 95% confidence interval, 1.00-1.25). In the second part, higher total blood loss after delivery was obtained (mean difference, 12.85 mL; 95% confidence interval, 3.28-22.42), and the result was unaltered when cohort studies were eliminated (mean difference, 13.72 mL; 95% confidence interval, 4.63-22.81). The conclusions are more likely to be obtained in developed countries.

CONCLUSION

Aspirin use during pregnancy is a potential risk of postpartum hemorrhage and does slightly increase the amount of postpartum blood loss. Without denying the combined value of aspirin, our conclusions raised an alarm for clinicians about postpartum hemorrhage in women using aspirin during pregnancy.

Redefining the Roles of Aspirin across the Spectrum of Cardiovascular Disease Prevention

Even before its role in platelet inhibition was fully characterized in the 1980s, aspirin had been incorporated into the cardiovascular disease care algorithm. Early trials examining its use in unstable angina and acute myocardial infarction revealed evidence of its protective role in the secondary prevention of atherosclerotic cardiovascular disease (ASCVD). Large trials assessing use in the primary prevention setting and optimal dosing regimens were studied in the late 1990s and early 2000s. As a cornerstone of cardiovascular care, aspirin was incorporated into primary and secondary ASCVD prevention guidelines in the United States and mechanical heart valve guidelines. However, in recent years, with significant advances in medical and interventional ASCVD therapies, scrutiny has been placed on the bleeding profile of aspirin, and guidelines have adapted to new evidence. Updates in primary prevention guidelines reserve aspirin only for patients at higher ASCVD risk and low bleeding risk - though questions remain in ASCVD risk assessment as risk-enhancing factors have proven difficult to incorporate on a population level. New thoughts regarding aspirin use in secondary prevention - especially with the concomitant use of anticoagulants - have altered recommendations as additional data accrued. Finally, a recommendation for aspirin and vitamin K antagonists with mechanical heart valves has been modified. Despite aspirin losing a foothold in cardiovascular care, new evidence has strengthened claims for its use in women at high risk for preeclampsia.

Effects of race and ethnicity on perinatal outcomes in high-income and upper-middle-income countries: an individual participant data meta-analysis of 2 198 655 pregnancies

BACKGROUND

Existing evidence on the effects of race and ethnicity on pregnancy outcomes is restricted to individual studies done within specific countries and health systems. We aimed to assess the impact of race and ethnicity on perinatal outcomes in high-income and upper-middle-income countries, and to ascertain whether the magnitude of disparities, if any, varied across geographical regions.

METHODS

For this individual participant data (IPD) meta-analysis we used data from the International Prediction of Pregnancy Complications (IPPIC) Network of studies on pregnancy complications; the full dataset comprised 94 studies, 53 countries, and 4 539 640 pregnancies. We included studies that reported perinatal outcomes (neonatal death, stillbirth, preterm birth, and small-for-gestational-age babies) in at least two racial or ethnic groups (White, Black, south Asian, Hispanic, or other). For our two-step random-effects IPD meta-analysis, we did multiple imputations for confounder variables (maternal age, BMI, parity, and level of maternal education) selected with a directed acyclic graph. The primary outcomes were neonatal mortality and stillbirth. Secondary outcomes were preterm birth and a small-for-gestational-age baby. We estimated the association of race and ethnicity with perinatal outcomes using a multivariate logistic regression model and reported this association with odds ratios (ORs) and 95% CIs. We also did a subgroup analysis of studies by geographical region.

FINDINGS

51 studies from 20 high-income and upper-middle-income countries, comprising 2 198 655 pregnancies, were eligible for inclusion in this IPD meta-analysis. Neonatal death was twice as likely in babies born to Black women than in babies born to White women (OR 2·00, 95% CI 1·44-2·78), as was stillbirth (2·16, 1·46-3·19), and babies born to Black women were at increased risk of preterm birth (1·65, 1·46-1·88) and being small for gestational age (1·39, 1·13-1·72). Babies of women categorised as Hispanic had a three-times increased risk of neonatal death (OR 3·34, 95% CI 2·77-4·02) than did those born to White women, and those born to south Asian women were at increased risk of preterm birth (OR 1·26, 95% CI 1·07-1·48) and being small for gestational age (1·61, 1·32-1·95). The effects of race and ethnicity on preterm birth and small-for-gestational-age babies did not vary across regions.

INTERPRETATION

Globally, among underserved groups, babies born to Black women had consistently poorer perinatal outcomes than White women after adjusting for maternal characteristics, although the risks varied for other groups. The effects of race and ethnicity on adverse perinatal outcomes did not vary by region.

FUNDING

National Institute for Health and Care Research, Wellbeing of Women.

Pregnancy outcomes and risk factors for preeclampsia in dichorionic twin pregnancies after in vitro fertilization: a five-year retrospective study

Background

Both in vitro fertilization (IVF) and preeclampsia (PE) were associated with placental dysfunction. Although IVF can increase the incidence of PE, the pregnancy outcomes and risk factors for preeclampsia in dichorionic twin pregnancies conceived via IVF remain unclear. This study aimed to investigate the pregnancy outcomes and the risk factors for preeclampsia in dichorionic twin pregnancies conceived through IVF compared to those conceived after natural conception (NC).

Methods

This retrospective observational study enrolled 181 dichorionic twin pregnancy women with preeclampsia from 2016 to 2020. According to the mode of conception, they were allocated into IVF (n = 117) and NC groups (n = 64). The clinical characteristics of preeclampsia and pregnancy outcomes between the two groups were compared by using Student’s t test, chi-square test, and Fisher’s exact test, and logistic regression models were used to obtain adjusted odds ratios (aOR) with 95% confidence intervals (CI) for risk factors of early-onset preeclampsia.

Results

The incidence of early-onset PE and growth discordance in dichorionic twin pregnancies with PE is significantly higher in IVF-PE group than in NC group (78.60% vs 43.80%, P < 0.001, 11.10% vs 25.00%, P = 0.015). We found that IVF (aOR = 4.635, 95% CI: 2.130–10.084, P < 0.001) and growth discordance (aOR = 3.288; 95% CI: 1.090–9.749, P < 0.05) increased the incidence of early-onset PE.

Conclusions

In preeclamptic dichorionic twin pregnancies, IVF and growth discordance were associated with the increased incidence of early-onset PE. The underlying mechanism for the relationship between IVF and early-onset PE or growth discordance may be placental dysfunction.

Aspirin for the prevention of preeclampsia: A systematic review and meta-analysis of randomized controlled studies

BACKGROUND

The results of randomized controlled studies on aspirin for the prevention of preeclampsia (PE) are conflicting, and some of the related meta-analyses also have limitations or flaws.

DATA SOURCES

A search was conducted on PubMed, Embase, and Cochrane Central Register of Controlled Trials databases, with no time or language restrictions.

STUDY ELIGIBILITY CRITERIA

Randomized controlled studies comparing aspirin for the prevention of PE were conducted.

METHODS

Systematic reviews were performed according to the Cochrane Manual guidelines. A fixed-effects model or a random-effects model was chosen to calculate pooled relative risks with 95% confidence intervals based on the heterogeneity of the included studies. The study aimed to investigate the effect of aspirin on the development of PE in high-risk and general populations of women. Publication bias was assessed by funnel plots. All included studies were assessed for bias by the Cochrane Manual of Bias Assessment. Subgroup analyses were conducted on the aspirin dose, time of initial aspirin intervention, and the region in which the research was conducted, to explore the effective dose of aspirin and time of initial aspirin intervention and to try to find sources of heterogeneity and publication bias.

RESULTS

A total of 39 articles were included, including 29 studies involving pregnant women at high risk for PE (20,133 patients) and 10 studies involving a general population of pregnant women (18,911 patients). Aspirin reduced the incidence of PE by 28% (RR 0.72, 95% CI 0.62-0.83) in women at high risk for PE. Aspirin reduced the incidence of PE by 30% in the general population (RR 0.70, 95% CI 0.52-0.95), but sensitivity analyses found that aspirin in the general population was not robust. A subgroup analysis showed that an aspirin dose of 75 mg/day (RR 0.50, 95% CI 0.32-0.78) had a better protective effect than other doses. Starting aspirin at 12-16 weeks (RR 0.62, 95% CI 0.53-0.74) of gestation or 17-28 weeks (RR 0.62, 95% CI 0.44-0.89) reduced the incidence of PE by 38% in women at high risk for PE, but the results were more reliable for use at 12-16 weeks. Heterogeneity and publication bias of the included studies may be mainly due to the studies completed in Asia.

CONCLUSION

Aspirin is recommended to be started at 12-16 weeks of pregnancy in women at high risk for PE. The optimal dose of aspirin to use is 75 mg/d.

SYSTEMATIC REVIEW REGISTRATION

[www.ClinicalTrials.gov], identifier [CRD42022319984].

Reviewing Accuracy of First Trimester Screening for Preeclampsia Using Maternal Factors and Biomarkers

Preeclampsia is a common and important complication of pregnancy, one with potentially significant morbidity and even mortality to both mother and baby. Identifying those at high risk of developing the condition is helpful as there is evidence that the incidence of preeclampsia can be reduced with low dose aspirin taken in pregnancy. Accurately predicting the risk of preeclampsia allows for more targeted aspirin prophylaxis and a greater opportunity for early detection of maternal and/or fetal complications associated with impaired placentation through a schedule of enhanced antenatal surveillance. Traditional preeclampsia prediction models use maternal characteristics and risk factors and have been shown to be of low predictive value. Multiparametric screening tests combine patient characteristics with serum biomarkers and ultrasound Doppler indices and have been shown to be more effective at detecting those at high risk of preeclampsia – more specifically, early-onset preeclampsia (onset of preeclampsia <34 weeks’ gestation). Multiparametric screening has now been validated in different populations. The true cost effectiveness of a multiparametric screening model for preeclampsia screening is not yet fully known and will vary depending on the clinical setting. Despite the growing body of evidence for its improved detection rates, first trimester preeclampsia screening using multiparametric models is not widely implemented and is not part of the recommendations for antenatal screening from most international bodies. The International Federation of Gynecology and Obstetrics has advised universal preeclampsia screening using maternal risk factors and biomarkers and has strongly encouraged its promotion worldwide. Various barriers to implementation must be considered such as the immediate cost of equipment and training, the need for audit and quality control, and the expected benefit to the population. Low to middle income settings may require a pragmatic approach to the implementation of multiparametric screening given limited resources.

Medications for preventing hypertensive disorders in high-risk pregnant women: a systematic review and network meta-analysis

OBJECTIVES

To determine the relative effectiveness of medications for preventing hypertensive disorders in high-risk pregnant women and to provide a ranking of medications using network meta-analysis.

METHODS

All randomized controlled trials comparing the most commonly used medications to prevent hypertensive disorders in high-risk pregnant women that are nulliparity and pregnant women having family history of preeclampsia, history of pregnancy-induced hypertension in previous pregnancy, obstetric risks, or underlying medical diseases. We received the search results from the Cochrane Pregnancy and Childbirth's Specialised Register of Controlled Trials, searched on 31st July 2020. At least two review authors independently selected the included studies and extracted the data and the methodological quality. The comparative risk ratios (RR) and 95% confidence intervals (CI) were analyzed using pairwise and network meta-analyses, and treatment rankings were estimated by the surface under the cumulative ranking curve for preventing preeclampsia (PE), gestational hypertension (GHT), and superimposed preeclampsia (SPE). Safety of the medications is also important for decision-making along with effectiveness which will be reported in a separate review.

RESULTS

This network meta-analysis included 83 randomized studies, involving 93,864 women across global regions. Three medications, either alone or in combination, probably prevented PE in high-risk pregnant women when compared with a placebo or no treatment from network analysis: antiplatelet agents with calcium (RR 0.19, 95% CI 0.04 to 0.86; 1 study; low-quality evidence), calcium (RR 0.61, 95% CI 0.47 to 0.80; 13 studies; moderate-quality evidence), antiplatelet agents (RR 0.69, 95% CI 0.57 to 0.82; 31 studies; moderate-quality evidence), and antioxidants (RR 0.77, 95% CI 0.63 to 0.93; 25 studies; moderate-quality evidence). Calcium probably prevented PE (RR 0.63, 95% CI 0.46 to 0.86; 11 studies; moderate-quality evidence) and GHT (RR 0.89, 95% CI 0.84 to 0.95; 8 studies; high-quality evidence) in nulliparous/primigravida women. Few included studies for the outcome of superimposed preeclampsia were found.

CONCLUSION

Antiplatelet agents, calcium, and their combinations were most effective medications for preventing hypertensive disorders in high-risk pregnant women when compared with a placebo or no treatment. Any high-risk characteristics for women are important in deciding the best medications. The qualities of evidence were mostly rated to be moderate.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018096276.

Association between aspirin use during pregnancy and cardiovascular risk factors 2-7 years after delivery: The nuMoM2b Heart Health Study

OBJECTIVES

To evaluate the association between aspirin use during first pregnancy and later maternal cardiovascular risk.

STUDY DESIGN

In this secondary analysis of a prospective cohort, we included participants who carried their first pregnancy to 20 + weeks, had data regarding aspirin use, and attended a study visit 2-7 years following delivery. The exposure was aspirin use during the first pregnancy. We calculated aspirin use propensity scores from logistic regression models including baseline variables associated with aspirin use in pregnancy and cardiovascular risk. Outcomes of interest were incident cardiovascular-related diagnoses 2-7 years following delivery. Robust Poisson regression calculated the risk of outcomes by aspirin exposure, adjusting for the aspirin use propensity score.

MAIN OUTCOME MEASURES

The primary outcome was a composite of incident cardiovascular diagnoses at the time of the study visit: cardiovascular events, chronic hypertension, metabolic syndrome, prediabetes or type 2 diabetes, dyslipidemia, and chronic kidney disease.

RESULTS

Of 4,480 women included, 84 (1.9%) reported taking aspirin during their first pregnancy. 52.6% of participants in the aspirin-exposed group and 43.0% in the unexposed group had the primary outcome. After adjusting for the aspirin use propensity scores, aspirin use during the first pregnancy was not associated with any of the outcomes.

CONCLUSION

We did not detect an association between aspirin use during the first pregnancy and cardiovascular-related diagnoses 2-7 years later. Our study was only powered to detect a large difference in relative risk, so we cannot rule out a smaller difference that may be clinically meaningful.

The role of aspirin dose and initiation time in the prevention of preeclampsia and corresponding complications: a meta-analysis of RCTs

PURPOSE

To investigate the role of different dosages and initial times of aspirin in preeclampsia prevention.

METHODS

This meta-analysis was performed based on randomized-control trials (RCTs). RCTs of women assigned to receive low-dose aspirin, placebo, or no treatment were included. Preeclampsia and corresponding complications were pooled for analysis. All studies were retrieved from PubMed, Embase, Cochrane and Web of Science.

RESULTS

A total of 46 studies were obtained in this meta-analysis, which consisted of 24,028 participants. When women at ≤ 16 gestational weeks started treatment with a dosage of < 100 mg/day aspirin, there was a significant reduction in the incidence of preeclampsia (RR = 0.75; 95% CI 0.58-0.98; P = 0.03), while in the subgroup receiving ≥ 100 mg/day aspirin, the result was RR = 0.71 (95% CI 0.53-0.95; P = 0.02). When aspirin was initiated at > 16 weeks, with a dosage of < 100 mg/day aspirin, there was a lesser preventive effect (RR = 0.80; 95% Cl 0.64-1.00; P = 0.05), and there was no significance in the subgroup receiving ≥ 100 mg/day aspirin (RR = 0.76; 95% Cl 0.45-1.31;  P =  0.32). Furthermore, aspirin was revealed to have a protective effect on reducing preterm delivery, but there was an increased risk of postpartum hemorrhage. No significant result was obtained for fetal loss.

CONCLUSION

The results of this meta-analysis suggest that high-risk pregnant women can prevent preeclampsia or preterm delivery by taking low-dose aspirin; the most efficient period is ≤ 16 weeks of gestation, and the best dose is ≥ 100 mg.

The Safety of Low-Dose Aspirin on the Mode of Delivery: Secondary Analysis of the Effect of Aspirin in Gestation and Reproduction Randomized Controlled Trial

OBJECTIVE

This study aimed to examine whether prenatal low-dose aspirin (LDA) therapy affects risk of cesarean versus vaginal delivery.

STUDY DESIGN

This study is a secondary analysis of the randomized clinical effects of aspirin in gestation and reproduction (EAGeR) trial. Women received 81-mg daily aspirin or placebo from preconception to 36 weeks of gestation. Mode of delivery and obstetric complications were abstracted from records. Log-binomial regression models estimated relative risk (RR) of cesarean versus vaginal delivery. Data were analyzed among the total preconception cohort, as well as restricted to women who had a live birth.

RESULTS

Among 1,228 women, 597 had a live birth. In the intent-to-treat analysis, preconception-initiated LDA was not associated with risk of cesarean (RR = 1.02; 95% confidence interval [CI]: 0.98-1.07) compared with placebo. Findings were similar in just women with a live birth and when accounting prior cesarean delivery and parity.

CONCLUSION

Preconception-initiated daily LDA was not associated with mode of delivery among women with one to two prior losses.

KEY POINTS

· Aspirin was not associated with risk of cesarean section.. · Aspirin was not associated with mode of delivery.. · No increased risk of bleeding with use of aspirin..

The prediction of preeclampsia: the way forward

Despite intensive investigation, we still cannot adequately predict, treat, or prevent preeclampsia. We have gained awareness that preeclampsia is a syndrome not a disease and is heterogeneous in its presentation and pathophysiology, which may indicate differing underlying phenotypes, and that the impact extends beyond pregnancy per se. Effects on the fetus and mother extend many years after pregnancy, as evidenced by fetal programming of adult disease and increased risk of the development of maternal cardiovascular disease. The increased occurrence of preeclampsia in women with preexisting risk factors suggests that the stress of pregnancy may expose subclinical vascular disease as opposed to preeclampsia damaging the vasculature. The heterogeneity of preeclampsia has blighted efforts to predict preeclampsia early in gestation and has thwarted success in attempts at therapy with treatments, such as low-dose aspirin or global antioxidants. There is a critical need to identify the phenotypes to enable their specific prediction and treatment. Such studies require considerably larger collections of patients than employed in past and current studies. This does not necessarily imply much larger patient numbers in single studies but can be facilitated by the ability to easily combine many smaller studies. This can be accomplished by agreeing on a priori standardized and harmonized clinical data and biospecimen collection across new studies. Such standards are being established by international groups of investigators. Leadership by international organizations, perhaps adopting a carrot and stick approach, to overcome investigator, institutional and funder reticence toward data sharing is required to ensure adoption of such standards. Future studies should include women in both low- and high-resource settings and employ social media and novel methods for data collection and analysis, including machine learning and artificial intelligence. The goal is to identify the pathophysiology underlying differing preeclampsia phenotypes, their successful prediction with the design, and the implementation of phenotype-specific therapies.

A randomized controlled trial of low-dose aspirin for the prevention of preeclampsia in women at high risk in China

BACKGROUND

Low-dose aspirin has been the most widely studied preventive drug for preeclampsia. However, guidelines differ considerably from country to country regarding the prophylactic use of aspirin for preeclampsia. There is limited evidence from large trials to determine the effect of 100 mg of aspirin for preeclampsia screening in women with high-risk pregnancies, based on maternal risk factors, and to guide the use of low-dose aspirin in preeclampsia prevention in China.

OBJECTIVE

The Low-Dose Aspirin in the Prevention of Preeclampsia in China study was designed to evaluate the effect of 100 mg of aspirin in preventing preeclampsia among high-risk pregnant women screened with maternal risk factors in China, where preeclampsia is highly prevalent, and the status of low-dose aspirin supply is commonly suboptimal.

STUDY DESIGN

We conducted a multicenter randomized controlled trial at 13 tertiary hospitals from 11 provinces in China between 2016 and 2019. We assumed that the relative reduction in the incidence of preeclampsia was at least 20%, from 20% in the control group to 16% in the aspirin group. Therefore, the targeted recruitment number was 1000 participants. Women were randomly assigned to the aspirin or control group in a 1:1 allocation ratio. Statistical analyses were performed according to an intention-to-treat basis. The primary outcome was the incidence of preeclampsia, diagnosed along with a systolic blood pressure of ≥140 mm Hg or a diastolic blood pressure of ≥90 mm Hg after 20 weeks of gestation, with a previously normal blood pressure (systolic blood pressure of <140 mm Hg and diastolic blood pressure of <90 mm Hg), and complicated by proteinuria. The secondary outcomes included maternal and neonatal outcomes. Logistic regression analysis was used to determine the significance of difference of preeclampsia incidence between the groups for both the primary and secondary outcomes. Interaction analysis was also performed.

RESULTS

A total of 1000 eligible women were recruited between December 2016 and March 2019, of which the final 898 patients were analyzed (464 participants in the aspirin group, 434 participants in the control group) on an intention-to-treat basis. No significant difference was found in preeclampsia incidence between the aspirin group (16.8% [78/464]) and the control group (17.1% [74/434]; relative risk, 0.986; 95% confidence interval, 0.738-1.317; P=.924). Likewise, adverse maternal and neonatal outcomes did not differ significantly between the 2 groups. Meanwhile, the incidence of postpartum hemorrhage between the 2 groups was similar (6.5% [30/464] in the aspirin group and 5.3% [23/434] in the control group; relative risk, 1.220; 95% confidence interval, 0.720-2.066; P=.459). We did not find any significant differences in preeclampsia incidence between the 2 groups in the subgroup analysis of the different risk factors.

CONCLUSION

A dosage of 100 mg of aspirin per day, initiated from 12 to 20 gestational weeks until 34 weeks of gestation, did not reduce the incidence of preeclampsia in pregnant women with high-risk factors in China.

External validation of prognostic models to predict stillbirth using International Prediction of Pregnancy Complications (IPPIC) Network database: individual participant data meta-analysis

OBJECTIVE

Stillbirth is a potentially preventable complication of pregnancy. Identifying women at high risk of stillbirth can guide decisions on the need for closer surveillance and timing of delivery in order to prevent fetal death. Prognostic models have been developed to predict the risk of stillbirth, but none has yet been validated externally. In this study, we externally validated published prediction models for stillbirth using individual participant data (IPD) meta-analysis to assess their predictive performance.

METHODS

MEDLINE, EMBASE, DH-DATA and AMED databases were searched from inception to December 2020 to identify studies reporting stillbirth prediction models. Studies that developed or updated prediction models for stillbirth for use at any time during pregnancy were included. IPD from cohorts within the International Prediction of Pregnancy Complications (IPPIC) Network were used to validate externally the identified prediction models whose individual variables were available in the IPD. The risk of bias of the models and cohorts was assessed using the Prediction study Risk Of Bias ASsessment Tool (PROBAST). The discriminative performance of the models was evaluated using the C-statistic, and calibration was assessed using calibration plots, calibration slope and calibration-in-the-large. Performance measures were estimated separately in each cohort, as well as summarized across cohorts using random-effects meta-analysis. Clinical utility was assessed using net benefit.

RESULTS

Seventeen studies reporting the development of 40 prognostic models for stillbirth were identified. None of the models had been previously validated externally, and the full model equation was reported for only one-fifth (20%, 8/40) of the models. External validation was possible for three of these models, using IPD from 19 cohorts (491 201 pregnant women) within the IPPIC Network database. Based on evaluation of the model development studies, all three models had an overall high risk of bias, according to PROBAST. In the IPD meta-analysis, the models had summary C-statistics ranging from 0.53 to 0.65 and summary calibration slopes ranging from 0.40 to 0.88, with risk predictions that were generally too extreme compared with the observed risks. The models had little to no clinical utility, as assessed by net benefit. However, there remained uncertainty in the performance of some models due to small available sample sizes.

CONCLUSIONS

The three validated stillbirth prediction models showed generally poor and uncertain predictive performance in new data, with limited evidence to support their clinical application. The findings suggest methodological shortcomings in their development, including overfitting. Further research is needed to further validate these and other models, identify stronger prognostic factors and develop more robust prediction models. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Eclampsia in the 21st century

The reported incidence of eclampsia is 1.6 to 10 per 10,000 deliveries in developed countries, whereas it is 50 to 151 per 10,000 deliveries in developing countries. In addition, low-resource countries have substantially higher rates of maternal and perinatal mortalities and morbidities. This disparity in incidence and pregnancy outcomes may be related to universal access to prenatal care, early detection of preeclampsia, timely delivery, and availability of healthcare resources in developed countries compared to developing countries. Because of its infrequency in developed countries, many obstetrical providers and maternity units have minimal to no experience in the acute management of eclampsia and its complications. Therefore, clear protocols for prevention of eclampsia in those with severe preeclampsia and acute treatment of eclamptic seizures at all levels of healthcare are required for better maternal and neonatal outcomes. Eclamptic seizure will occur in 2% of women with preeclampsia with severe features who are not receiving magnesium sulfate and in <0.6% in those receiving magnesium sulfate. The pathogenesis of an eclamptic seizure is not well understood; however, the blood-brain barrier disruption with the passage of fluid, ions, and plasma protein into the brain parenchyma remains the leading theory. New data suggest that blood-brain barrier permeability may increase by circulating factors found in preeclamptic women plasma, such as vascular endothelial growth factor and placental growth factor. The management of an eclamptic seizure will include supportive care to prevent serious maternal injury, magnesium sulfate for prevention of recurrent seizures, and promoting delivery. Although routine imagining following an eclamptic seizure is not recommended, the classic finding is referred to as the posterior reversible encephalopathy syndrome. Most patients with posterior reversible encephalopathy syndrome will show complete resolution of the imaging finding within 1 to 2 weeks, but routine imaging follow-up is unnecessary unless there are findings of intracranial hemorrhage, infraction, or ongoing neurologic deficit. Eclampsia is associated with increased risk of maternal mortality and morbidity, such as placental abruption, disseminated intravascular coagulation, pulmonary edema, aspiration pneumonia, cardiopulmonary arrest, and acute renal failure. Furthermore, a history of eclamptic seizures may be related to long-term cardiovascular risk and cognitive difficulties related to memory and concentration years after the index pregnancy. Finally, limited data suggest that placental growth factor levels in women with preeclampsia are superior to clinical markers in prediction of adverse pregnancy outcomes. This data may be extrapolated to the prediction of eclampsia in future studies. This summary of available evidence provides data and expert opinion on possible pathogenesis of eclampsia, imaging findings, differential diagnosis, and stepwise approach regarding the management of eclampsia before delivery and after delivery as well as current recommendations for the prevention of eclamptic seizures in women with preeclampsia.

Prevention of preeclampsia with aspirin

Preeclampsia is defined as hypertension arising after 20 weeks of gestational age with proteinuria or other signs of end-organ damage and is an important cause of maternal and perinatal morbidity and mortality, particularly when of early onset. Although a significant amount of research has been dedicated in identifying preventive measures for preeclampsia, the incidence of the condition has been relatively unchanged in the last decades. This could be attributed to the fact that the underlying pathophysiology of preeclampsia is not entirely understood. There is increasing evidence suggesting that suboptimal trophoblastic invasion leads to an imbalance of angiogenic and antiangiogenic proteins, ultimately causing widespread inflammation and endothelial damage, increased platelet aggregation, and thrombotic events with placental infarcts. Aspirin at doses below 300 mg selectively and irreversibly inactivates the cyclooxygenase-1 enzyme, suppressing the production of prostaglandins and thromboxane and inhibiting inflammation and platelet aggregation. Such an effect has led to the hypothesis that aspirin could be useful for preventing preeclampsia. The first possible link between the use of aspirin and the prevention of preeclampsia was suggested by a case report published in 1978, followed by the first randomized controlled trial published in 1985. Since then, numerous randomized trials have been published, reporting the safety of the use of aspirin in pregnancy and the inconsistent effects of aspirin on the rates of preeclampsia. These inconsistencies, however, can be largely explained by a high degree of heterogeneity regarding the selection of trial participants, baseline risk of the included women, dosage of aspirin, gestational age of prophylaxis initiation, and preeclampsia definition. An individual patient data meta-analysis has indicated a modest 10% reduction in preeclampsia rates with the use of aspirin, but later meta-analyses of aggregate data have revealed a dose-response effect of aspirin on preeclampsia rates, which is maximized when the medication is initiated before 16 weeks of gestational age. Recently, the Aspirin for Evidence-Based Preeclampsia Prevention trial has revealed that aspirin at a daily dosage of 150 mg, initiated before 16 weeks of gestational age, and given at night to a high-risk population, identified by a combined first trimester screening test, reduces the incidence of preterm preeclampsia by 62%. A secondary analysis of the Aspirin for Evidence-Based Preeclampsia Prevention trial data also indicated a reduction in the length of stay in the neonatal intensive care unit by 68% compared with placebo, mainly because of a reduction in births before 32 weeks of gestational age with preeclampsia. The beneficial effect of aspirin has been found to be similar in subgroups according to different maternal characteristics, except for the presence of chronic hypertension, where no beneficial effect is evident. In addition, the effect size of aspirin has been found to be more pronounced in women with good compliance to treatment. In general, randomized trials are underpowered to investigate the treatment effect of aspirin on the rates of other placental-associated adverse outcomes such as fetal growth restriction and stillbirth. This article summarizes the evidence around aspirin for the prevention of preeclampsia and its complications.

Prediction of twin pregnancy preeclampsia based on clinical risk factors, early pregnancy serum markers, and uterine artery pulsatility index

Objectives:

To investigate whether a combination of clinical risk factors, early pregnancy serum markers, and uterine artery pulsatility index (UTPI) can be used to predict twin preeclampsia (PE).

Methods:

This case control study included women with twin pregnancies who had undergone obstetrics treatments and gave birth at the Huzhou Maternity and Child Health Care Hospital from October 2018 to November 2020. Patients with PE comprised study group, and patients without PE comprised control group based on selection criteria and a 1:1 ratio. Statistical analysis was performed using clinical risk factors, early pregnancy serum markers, and UTPIs, and the area under the receiver operating curve (AUC. Sensitivity, and the specificity of different combinations of these variables were calculated to predict PE in women with twin pregnancy.

Results:

Logistic regression analysis revealed four independent predictors for the onset of PE during twin pregnancies: first delivery (OR, 7.51; P=0.045), conception method (OR, 7.11; P=0.036), β-HCG level (per SD OR, 2.73; P=0.026), and UTPI (OR, 0.17; P=0.043). First-delivery and IVF pregnancy methods both lead to a 7-fold increase in the PE risk during twin pregnancies. Every one sigma (standard deviation) increase in the β-HCG level led to a 2.73-fold increase in the PE risk. Every UTPI increment by 1.0 reduces the risk of PE by 83%. The prediction efficiencies were based on an AUC of 0.837, a sensitivity of 69%, and a specificity of 92% for the clinical risk factors; an AUC of 0.800, a sensitivity of 81%, and specificity of 78% for the β-HCG level, and an AUC of 0.814, a sensitivity of 88%, and a specificity of 65% for the UTPI. AUC was 0.928, sensitivity 85%, and a specificity 88% after applying the three types of indicators together for prediction.

Conclusions:

By combining early pregnancy serum markers (β-HCG), and UTPI, the predictive value for PE during twin pregnancy is improved together with its sensitivity and specificity.

Validation and development of models using clinical, biochemical and ultrasound markers for predicting pre-eclampsia: an individual participant data meta-analysis

BACKGROUND

Pre-eclampsia is a leading cause of maternal and perinatal mortality and morbidity. Early identification of women at risk is needed to plan management.

OBJECTIVES

To assess the performance of existing pre-eclampsia prediction models and to develop and validate models for pre-eclampsia using individual participant data meta-analysis. We also estimated the prognostic value of individual markers.

DESIGN

This was an individual participant data meta-analysis of cohort studies.

SETTING

Source data from secondary and tertiary care.

PREDICTORS

We identified predictors from systematic reviews, and prioritised for importance in an international survey.

PRIMARY OUTCOMES

Early-onset (delivery at < 34 weeks' gestation), late-onset (delivery at ≥ 34 weeks' gestation) and any-onset pre-eclampsia.

ANALYSIS

We externally validated existing prediction models in UK cohorts and reported their performance in terms of discrimination and calibration. We developed and validated 12 new models based on clinical characteristics, clinical characteristics and biochemical markers, and clinical characteristics and ultrasound markers in the first and second trimesters. We summarised the data set-specific performance of each model using a random-effects meta-analysis. Discrimination was considered promising for C-statistics of ≥ 0.7, and calibration was considered good if the slope was near 1 and calibration-in-the-large was near 0. Heterogeneity was quantified using I ² and τ². A decision curve analysis was undertaken to determine the clinical utility (net benefit) of the models. We reported the unadjusted prognostic value of individual predictors for pre-eclampsia as odds ratios with 95% confidence and prediction intervals.

RESULTS

The International Prediction of Pregnancy Complications network comprised 78 studies (3,570,993 singleton pregnancies) identified from systematic reviews of tests to predict pre-eclampsia. Twenty-four of the 131 published prediction models could be validated in 11 UK cohorts. Summary C-statistics were between 0.6 and 0.7 for most models, and calibration was generally poor owing to large between-study heterogeneity, suggesting model overfitting. The clinical utility of the models varied between showing net harm to showing minimal or no net benefit. The average discrimination for IPPIC models ranged between 0.68 and 0.83. This was highest for the second-trimester clinical characteristics and biochemical markers model to predict early-onset pre-eclampsia, and lowest for the first-trimester clinical characteristics models to predict any pre-eclampsia. Calibration performance was heterogeneous across studies. Net benefit was observed for International Prediction of Pregnancy Complications first and second-trimester clinical characteristics and clinical characteristics and biochemical markers models predicting any pre-eclampsia, when validated in singleton nulliparous women managed in the UK NHS. History of hypertension, parity, smoking, mode of conception, placental growth factor and uterine artery pulsatility index had the strongest unadjusted associations with pre-eclampsia.

LIMITATIONS

Variations in study population characteristics, type of predictors reported, too few events in some validation cohorts and the type of measurements contributed to heterogeneity in performance of the International Prediction of Pregnancy Complications models. Some published models were not validated because model predictors were unavailable in the individual participant data.

CONCLUSION

For models that could be validated, predictive performance was generally poor across data sets. Although the International Prediction of Pregnancy Complications models show good predictive performance on average, and in the singleton nulliparous population, heterogeneity in calibration performance is likely across settings.

FUTURE WORK

Recalibration of model parameters within populations may improve calibration performance. Additional strong predictors need to be identified to improve model performance and consistency. Validation, including examination of calibration heterogeneity, is required for the models we could not validate.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015029349.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 72. See the NIHR Journals Library website for further project information.

Aspirin Use to Prevent Preeclampsia and Related Morbidity and Mortality: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Preeclampsia is a hypertensive disorder of pregnancy that poses serious maternal and infant health risks. Previous systematic reviews have established benefits of low-dose aspirin taken during pregnancy to prevent preeclampsia and its sequelae.

OBJECTIVE

To update evidence for the US Preventive Services Task Force (USPSTF) on effectiveness of aspirin use in preventing preeclampsia in individuals at increased risk based on clinical risk factors or measurements associated with higher disease incidence than in the general population.

DATA SOURCES

Studies from previous USPSTF review (2014), literature published January 2013 through May 15, 2020, in MEDLINE, PubMed (for publisher-supplied records only), EMBASE, and Cochrane Central Register of Controlled Trials. Ongoing surveillance through January 22, 2021.

STUDY SELECTION

Good- and fair-quality randomized clinical trials (RCTs) of low-dose aspirin use during pregnancy to prevent preeclampsia among individuals at increased risk; studies conducted in general populations to evaluate potential harms.

DATA EXTRACTION AND SYNTHESIS

Dual article screening and risk-of-bias assessment. Study data abstracted into prespecified forms, checked for accuracy. Random-effects meta-analysis.

MAIN OUTCOMES AND MEASURES

Diagnosis of preeclampsia; adverse pregnancy health outcomes and complications including eclampsia, perinatal mortality, preterm birth, small for gestational age, and potential bleeding harms or infant/child harms from aspirin exposure.

RESULTS

A total of 23 randomized clinical trials (RCTs) (N = 26 952) were included; 18 were conducted among participants at increased preeclampsia risk. Aspirin dosages ranged from 50 mg/d to 150 mg/d. Most trials enrolled majority White populations selected based on a range of risk factors. The incidence of preeclampsia among the trials of participants at increased risk ranged from 4% to 30%. Aspirin use was significantly associated with lower risk of preeclampsia (pooled relative risk [RR], 0.85 [95% CI, 0.75-0.95]; 16 RCTs [n = 14 093]; I2 = 0%), perinatal mortality (pooled RR, 0.79 [95% CI, 0.66-0.96]; 11 RCTs [n = 13 860]; I2 = 0%), preterm birth (pooled RR, 0.80 [95% CI, 0.67-0.95]; 13 RCTs [n = 13 619]; I2 = 49%), and intrauterine growth restriction (pooled RR, 0.82 [95% CI, 0.68-0.99]; 16 RCTs [n = 14 385]; I2 = 41%). There were no significant associations of aspirin use with risk of postpartum hemorrhage (pooled RR, 1.03 [95% CI, 0.94-1.12]; 9 RCTs [n = 23 133]; I2 = 0%) and other bleeding-related harms, or with rare perinatal or longer-term harms. Absolute risk reductions for preeclampsia associated with aspirin use ranged from -1% to -6% across larger trials (n >300) and were greater in smaller trials. For perinatal mortality, absolute risk reductions ranged from 0.5% to 1.1% in the 3 largest trials.

CONCLUSIONS AND RELEVANCE

Daily low-dose aspirin during pregnancy was associated with lower risks of serious perinatal outcomes for individuals at increased risk for preeclampsia, without evident harms.

Outcomes Associated With Hypertensive Disorders of Pregnancy in Twin Compared With Singleton Gestations

OBJECTIVE

To evaluate whether pregnancy outcomes associated with hypertensive disorders of pregnancy in twin pregnancies differ relatively from those in singleton pregnancy.

METHODS

We conducted a retrospective, population-based cohort study of all women with a liveborn singleton or twin hospital birth in Ontario, Canada, between 2012 and 2019. Data were obtained from the Better Outcomes Registry & Network Ontario. Pregnancy outcomes were compared between women with and without hypertensive disorders of pregnancy in twin gestations, and separately in singleton gestations. Adjusted relative risks (aRRs) and 95% CIs were generated using modified Poisson regression and were compared between twins and singletons using relative risk ratios.

RESULTS

Overall, 932,218 women met the study criteria, of whom 917,542 (98.4%) and 14,676 (1.6%) had singleton and twin gestations, respectively. The incidence of hypertensive disorders of pregnancy was higher in women with twin compared with singleton gestations (14.4% vs 6.4%, aRR 1.85 [1.76-1.94]). Hypertensive disorders of pregnancy were associated with certain adverse outcomes in singleton gestations only and with other adverse outcomes in both the singleton and twin gestations, but the aRR was lower in twins. For example, preterm birth before 37 weeks of gestation (singletons: 15.2% [hypertensive disorders of pregnancy] vs 5.4% [no hypertensive disorders of pregnancy], aRR 2.42; twins: 67.5% [hypertensive disorders of pregnancy] vs 50.4% [no hypertensive disorders of pregnancy], aRR 1.30) and neonatal respiratory morbidity (singletons: 16.3% [hypertensive disorders of pregnancy] vs 8.7% [no hypertensive disorders of pregnancy], aRR 1.50; twins: 39.8% [hypertensive disorders of pregnancy] vs 32.7% [no hypertensive disorders of pregnancy], aRR 1.13). These findings persisted in the subgroups of women with preeclampsia and early-onset preeclampsia.

CONCLUSIONS

Although the absolute risk of adverse maternal and neonatal outcomes is higher in twin compared with singleton pregnancies, the incremental risk of adverse outcomes associated with hypertensive disorders in twin pregnancies is lower than the incremental risk in singleton pregnancies. These findings may be attributed in part to the higher baseline risk of preterm birth and adverse maternal and perinatal outcomes in twin compared with singleton pregnancies.

Aspirin Prophylaxis During Pregnancy: A Systematic Review and Meta-Analysis

CONTEXT

Low-dose aspirin is used for pre-eclampsia prophylaxis during pregnancy, but a study that comprehensively investigates both maternal and perinatal outcomes from aspirin administration utilizing stratification methods is lacking. The aim of this study is to comprehensively investigate the maternal and neonatal outcomes related to aspirin prophylaxis during pregnancy in relation to dose and therapy initiation by utilizing a stratification method.

EVIDENCE ACQUISITION

Placebo-controlled randomized trials investigating the effect of low-dose aspirin on maternal or perinatal outcomes with sufficient raw data and published in English from inception to August 2020 were searched for from PubMed, Embase, Cochrane Library, and Google Scholar in accordance with PRISMA guidelines. Review articles, editorials, case reports, conference abstracts, and nonplacebo-controlled studies were excluded.

EVIDENCE SYNTHESIS

A total of 35 placebo-controlled randomized trials with 46,568 pregnant women were included in this meta-analysis. Aspirin prophylaxis substantially lowered the risk of pre-eclampsia, preterm birth, perinatal mortality, and intrauterine growth retardation without elevated bleeding risks. Low-dose aspirin considerably enhanced neonatal birth weight but did not decrease the risk of gestational hypertension. The subgroup analysis revealed substantially reduced pre-eclampsia risk and enhanced birth weight and gestational age at delivery in women who initiated aspirin before 20 weeks of gestation (RR=0.76, 95% CI=0.64, 0.90, p=0.001). However, the effect of aspirin dose on pregnancy outcomes was insignificant and requires further evaluation.

CONCLUSIONS

Initiation of low-dose aspirin administration before 20 weeks of gestation considerably decreases the incidence of pre-eclampsia and related neonatal outcomes without increasing bleeding risk.

The Road to Low-Dose Aspirin Therapy for the Prevention of Preeclampsia Began with the Placenta

The road to low-dose aspirin therapy for the prevention of preeclampsia began in the 1980s with the discovery that there was increased thromboxane and decreased prostacyclin production in placentas of preeclamptic women. At the time, low-dose aspirin therapy was being used to prevent recurrent myocardial infarction and other thrombotic events based on its ability to selectively inhibit thromboxane synthesis without affecting prostacyclin synthesis. With the discovery that thromboxane was increased in preeclamptic women, it was reasonable to evaluate whether low-dose aspirin would be effective for preeclampsia prevention. The first clinical trials were very promising, but then two large multi-center trials dampened enthusiasm until meta-analysis studies showed aspirin was effective, but with caveats. Low-dose aspirin was most effective when started <16 weeks of gestation and at doses >100 mg/day. It was effective in reducing preterm preeclampsia, but not term preeclampsia, and patient compliance and patient weight were important variables. Despite the effectiveness of low-dose aspirin therapy in correcting the placental imbalance between thromboxane and prostacyclin and reducing oxidative stress, some aspirin-treated women still develop preeclampsia. Alterations in placental sphingolipids and hydroxyeicosatetraenoic acids not affected by aspirin, but with biologic actions that could cause preeclampsia, may explain treatment failures. Consideration should be given to aspirin's effect on neutrophils and pregnancy-specific expression of protease-activated receptor 1, as well as additional mechanisms of action to prevent preeclampsia.

Aspirin for preventing adverse outcomes in low risk nulliparous women with singleton pregnancies: A systematic review and meta-analysis

OBJECTIVE

To assess the effects of aspirin in pregnancy for the prevention of adverse outcomes in low risk, nulliparous women with singleton pregnancies.

STUDY DESIGN

Medline, Embase, CINAHL, the Cochrane library, Web of Science and clinicaltrials.gov were searched from inception until February 2020. Randomised controlled trials were eligible for inclusion where women were nulliparous, had singleton pregnancies and no other risk factors for pre-eclampsia such as diabetes or pre-existing hypertension. Primary outcomes were pre-eclampsia, gestational hypertension and eclampsia. Secondary outcomes included; pre-term birth, postpartum haemorrhage, antepartum haemorrhage, miscarriage, small for gestational age (SGA), fetal growth restriction (FGR), birthweight and further markers of maternal and neonatal morbidity and mortality. The results were combined into meta-analysis where appropriate.

RESULTS

Ten studies were eligible for inclusion involving 23,162 women. Two studies (involving 214 women) used aspirin doses of 100 mg, with the remainder using smaller doses. There was no significant difference found in the risk of developing pre-eclampsia between women receiving aspirin compared to no aspirin (relative risk [RR] 0.70, 95 % confidence interval [CI] 0.47-1.05, p = 0.08). Women receiving aspirin had a reduced risk of having a preterm birth <34 weeks (RR 0.50, 95 % CI 0.26-0.96, p = 0.04), and reduced risk of having a SGA neonate (RR 0.94, 95 % CI 0.89-1.00, p = 0.04). An increase in birthweight was seen when aspirin was received (mean difference 105.17 g, 95 % CI 12.38 g-197.96 g, p = 0.03) and there was no increase in risk of postpartum or antepartum haemorrhage in those receiving aspirin (RR 1.24, 95 % CI 0.90-1.71, p = 0.19 and RR 1.06, 95 % CI 0.66-1.70, p = 0.81 respectively).

CONCLUSION

The results did not demonstrate a significant difference amongst low risk nulliparous women in the risks of pre-eclampsia or gestational hypertensive disorders with aspirin administration. Although we found significantly improved fetal growth parameters and prevention of preterm birth in women receiving aspirin, there were few eligible studies, with those included generally providing low quality evidence and many studies using aspirin doses ≤100 mg, commenced late in pregnancy. More research in the form of a high quality randomised controlled trial is needed before recommendations can be made.

Subtypes of Preeclampsia: Recognition and Determining Clinical Usefulness

The concept that preeclampsia is a multisystemic syndrome is appreciated in both research and clinical care. Our understanding of pathophysiology recognizes the role of inflammation, oxidative and endoplasm reticulum stress, and angiogenic dysfunction. Yet, we have not progressed greatly toward clinically useful prediction nor had substantial success in prevention or treatment. One possibility is that the maternal syndrome may be reached through different pathophysiological pathways, that is, subtypes of preeclampsia, that in their specificity yield more clinical utility. For example, early and late onset preeclampsia are increasingly acknowledged as different pathophysiological processes leading to a common presentation. Other subtypes of preeclampsia are supported by disparate clinical outcomes, long-range prognosis, organ systems involved, and risk factors. These insights have been supplemented by discovery-driven methods, which cluster preeclampsia cases into groups indicating different pathophysiologies. In this presentation, we review likely subtypes based on current knowledge and suggest others. We present a consideration of the requirements for a clinically meaningful preeclampsia subtype. A useful subtype should (1) identify a specific pathophysiological pathway or (2) specifically indicate maternal or fetal outcome, (3) be recognizable in a clinically useful time frame, and (4) these results should be reproducible and generalizable (but at varying frequency) including in low resource settings. We recommend that the default consideration be that preeclampsia includes several subtypes rather than trying to force all cases into a single pathophysiological pathway. The recognition of subtypes and deciphering their different pathophysiologies will provide specific targets for prevention, prediction, and treatment directing personalized care.

The Impact of the New Hypertension Guidelines to Low-Dose Aspirin Prophylaxis Eligibility for the Prevention of Preeclampsia: A Cost-Benefit Analysis

OBJECTIVE

American College of Cardiology and American Heart Association (ACC/AHA) published new guidelines which lower the cut-off for hypertension. We sought to evaluate the impact of these guidelines to cost and benefit of various low-dose aspirin prophylaxis approaches.

STUDY DESIGN

Decision tree analysis was created using R software to evaluate four approaches to aspirin prophylaxis in the United States: no aspirin, United States Preventive Service Task Force (USPSTF) with Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) hypertension guidelines, USPSTF with ACC/AHA hypertension guidelines, as well as universal aspirin prophylaxis. This model was executed to simulate a hypothetical cohort of 4 million pregnant women in the United States.

RESULTS

The new guidelines would expand the aspirin eligibility by 8% (76,953 women) in the USPSTF guidelines. Even with this increased eligibility, the USPSTF guidelines continue to be the approach with the most cost savings ($386.5 million) when compared with universal aspirin and no aspirin prophylaxis. The new hypertension guidelines are projected to increase the cost savings of the USPSTF approach by $9.4 million.

CONCLUSION

Despite the small change in aspirin prophylaxis, using ACC/AHA definition of hypertension still results in an annual cost-saving of $9.4 million in the United States when compared with JNC7.

Spontaneous Preterm Birth: Is Prevention with Aspirin Possible?

Background The rate of preterm births in Germany is 8.6%, which is very high compared to other European countries. As preterm birth contributes significantly to perinatal morbidity and mortality rates, the existing prevention strategies need to be optimized and expanded further. About ⅔ of all women with preterm birth have preterm labor or premature rupture of membranes. They are bracketed together under the term “spontaneous preterm birth” as opposed to iatrogenic preterm birth, for example as a consequence of preeclampsia or fetal growth retardation. Recent studies suggest that low-dose aspirin does not just reduce the rate of iatrogenic preterm births but can also further reduce the rate of spontaneous preterm births. This review article presents the current state of knowledge.

Method A selective literature search up until April 2020 was done in PubMed, using the terms “randomized trial”, “randomized study”, “spontaneous preterm birth”, and “aspirin”.

Results Secondary analyses of prospective randomized studies on the prevention of preeclampsia with low-dose aspirin show that this intervention also significantly reduced the rate of spontaneous preterm births in both high-risk and low-risk patient populations. The results of the ASPIRIN trial, a prospective, randomized, double-blinded multicenter study carried out in six developing countries, also point in this direction, with the figures showing that the daily administration of 81 mg aspirin starting before 14 weeks of gestation lowered the preterm birth rate of nulliparous women without prior medical conditions by around 11% (11.6 vs. 13.1%; RR 0.89; 95% CI: 0.81 – 0.98, p = 0.012).

Conclusion Further studies on this issue are urgently needed. If these confirm the currently available results, then it would be worth discussing whether general aspirin prophylaxis for all pregnant women starting at the latest in 12 weeks of gestation is indicated.

Preventive effect of aspirin on preeclampsia in high-risk pregnant women with stage 1 hypertension

Studies reported that women in a low‐risk cohort with stage 1 hypertension defined as 130–139 mmHg/80–89 mmHg, according to the American College of Cardiology/American Heart Association, are more likely to develop into preeclampsia than women with normotensive in the early gestation. In this study, the authors investigated whether preeclampsia was more likely to occur in stage 1 hypertensive women compared to the normotensive pregnant women in a high‐risk cohort, which was based on the randomized controlled trial of "Low‐dose Aspirin in the Prevention of Preeclampsia in China." Meanwhile, the authors further evaluated the preventive effect of aspirin for preeclampsia in stage 1 hypertension subset. In women enrolled at or before 16 weeks of gestation, in the control group, the preeclampsia occurrence was significantly higher in stage 1 hypertensive woman than in the normotensive women (20.4% vs. 6.2%, aOR 3.960, 95% CI 1.299–12.074, p = .016), while no difference was observed in the aspirin group (4.5% vs. 4.2%, aOR 0.921, 95% CI 0.140–6.070, p = .932). In stage 1 hypertension, the incidences of preeclampsia and preterm birth were significantly lower in the aspirin group as compared to the control group (4.5% vs. 20.4%, aOR 0.139, 95% CI 0.027–0.716, p = .018; 4.5% vs. 18.4%, aOR 0.141, 95% CI 0.025–0.782, p = .025). Compared with the control group, the aspirin group displayed significantly prolonged gestational age at delivery (38.6 ± 1.2 vs. 37.4 ± 3.4, p = .042). This study indicates that the newly classified stage 1 hypertension might be an additional risk factor for preeclampsia in Chinese high‐risk pregnant women, and aspirin intervention might be useful.

The Role of Aspirin for Preeclampsia Prevention in Women with Diabetes

PURPOSE OF REVIEW

A diagnosis of type I or type 2 diabetes confers heightened risk for virtually every obstetric and perinatal complication, with the incidence of superimposed preeclampsia representing a particularly high-risk scenario. Over the past three decades, studies have investigated the role of aspirin in preeclampsia prevention, yielding some promising results for certain at-risk groups, yet unconvincing evidence of benefit among women with pre-pregnancy diabetes. The purpose of this review is to present the current evidence base for aspirin use in pregnancy as a means of mitigating preeclampsia risk in the setting of pregestational type I or type 2 diabetes.

RECENT FINDINGS

Meta-analysis data examining low-dose aspirin for preeclampsia prevention in at-risk and low-risk women has demonstrated modest benefit, but subanalyses of cohorts with diabetes have failed to demonstrate a beneficial effect. Evidence is emerging that indicates a benefit only among women who initiate aspirin therapy prior to 16 weeks' gestation, and uncertainty exists surrounding the effective dose. In light of equipoise surrounding the potential role of aspirin for prevention of preeclampsia in women with diabetes, current research is targeted at determining clinical efficacy of aspirin in this high-risk obstetric population.

Low-dose aspirin for preeclampsia prevention: efficacy by ethnicity and race

BACKGROUND

Low-dose aspirin is recommended for the prevention of preeclampsia among women at a high risk of developing the disease. Aspirin undergoes polymorphic metabolism, and it is well known that common genetic polymorphisms are related to aspirin intolerance. We hypothesized that the efficacy of aspirin prophylaxis may differ by ethnicity and race.

OBJECTIVE

This study aimed to compare the rates of preeclampsia among low- and high-risk women who received aspirin compared with placebo, stratifying results by ethnicity and race as a first-pass approximation of genomic polymorphisms.

STUDY DESIGN

This is a secondary analysis of 2 randomized controlled trials previously performed by the Maternal-Fetal Medicine Units Network: the Low-Risk Aspirin trial and the High-Risk Aspirin trial. For the Low-Risk Aspirin trial, normotensive, nulliparous women were enrolled between 13 and 26 weeks' gestation and randomized to 60 mg aspirin daily or placebo. For the High-Risk Aspirin trial, women with pregestational insulin-treated diabetes mellitus, chronic hypertension, multiple gestations, or a history of preeclampsia in a previous pregnancy were enrolled between 13 and 26 weeks' gestation and randomized to 60 mg aspirin daily or placebo. The primary outcome of our secondary analysis was preeclampsia. Secondary outcomes included gestational age at delivery, preterm delivery, placental abruption, small for gestational age, stillbirth, and neonatal death. Outcomes were stratified by ethnicity and race (Hispanic, non-Hispanic white, non-Hispanic black, or other).

RESULTS

In the Low-Risk Aspirin trial of 3135 women, the risk of preeclampsia was significantly reduced among non-Hispanic white women who received aspirin compared with non-Hispanic white women who received placebo (relative risk, 0.19; 95% confidence interval, 0.06-0.63; P=.007). The risk of preeclampsia was not different when comparing the aspirin and placebo groups among the Hispanic, non-Hispanic black, or other ethnicity and race groups. The efficacy among non-Hispanic white women persisted after consideration of compliance and gestational age at randomization (relative risk, 0.07; 95% confidence interval, 0.009-0.51; P=.009). As noted in the original trial, there was an increased risk of placental abruption in the aspirin group overall compared with placebo (P=.025). The risk of stillbirth was significantly increased among non-Hispanic black women who received aspirin compared with non-Hispanic black women who received placebo (P=.048). In the High-Risk Aspirin trial of 2539 women, 269 were Hispanic (10.6%), 832 were non-Hispanic white (32.8%), 1426 were non-Hispanic black (56.2%), and 12 were categorized as other (0.5%). Stratification by ethnicity and race did not reveal a decreased incidence of preeclampsia for any of the subgroups (P>.05). Moreover, there was no significant difference in other measured outcomes including preterm delivery at <37 weeks' gestation, placental abruption, small for gestational age, stillbirth, or neonatal death.

CONCLUSION

The incidence of preeclampsia was significantly reduced among low-risk non-Hispanic white women who received aspirin compared with placebo (P=.007), but not overall or among Hispanic or non-Hispanic black women. The analysis of high-risk women did not indicate a difference in the efficacy of aspirin by ethnicity and race.

Effects of low-dose aspirin on the prevention of preeclampsia and pregnancy outcomes: A randomized controlled trial from Shanghai, China

OBJECTIVES

To evaluate the preventive effects of low-dose aspirin on the incidence of preeclampsia and pregnancy outcomes of women at high-risk for preeclampsia.

STUDY DESIGN

This prospective randomized clinical trial was conducted at the Obstetrics Department of The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, China. It analyzed data from 1105 high-risk women who were divided into the control group (placebo group) and the aspirin group (including three subgroups: 25 mg, 50 mg and 75 mg). The aspirin group in this study was instructed to take aspirin daily before bedtime beginning in the 12th week of pregnancy.

MAIN OUTCOME MEASURES

The primary outcome is the occurrence of preeclampsia. The secondary outcomes included maternal and neonatal outcomes (such as premature delivery, FGR etc.), maternal serum biomarkers (including d-dimers, platelet aggregation rates, etc.) and uterine arterial blood flow resistance. The onset of preeclampsia and pregnancy outcomes were recorded after all participants delivered.

RESULTS

Low-dose aspirin significantly reduced the incidence of preeclampsia and early-onset preeclampsia. Aspirin also showed significant dose dependence in preeclampsia prevention. The results of Mantel-Haenszel trend test showed that there was a linear relationship between the dosage and the incidence of preeclampsia and early preeclampsia (P < 0.05). Pearson's results showed that the incidence of preeclampsia and early preeclampsia was negatively correlated with aspirin dosage. There was also a linear relationship between the dosage and the rates of postpartum hemorrhage, fetal growth restriction, premature births and cesarean section (P < 0.05). There was no evidence to suggest differences in the incidence of fetal distress, miscarriage and placental abruption among the four groups. The blood resistance S/D value of uterine artery in early pregnancy was the only independent factor affecting the efficacy of aspirin (OR = 1.405; 95 %CI,1.058-1.867; P = 0.019).

CONCLUSION

Low-dose aspirin can prevent preeclampsia and early-preeclampsia. Its efficacy is dose-dependent. It can reduce the rates of postpartum hemorrhage, fetal growth restriction, premature births and cesarean section. The prophylactic effect of aspirin on preeclampsia seemed to be greater in patients with higher blood resistance S/D value of uterine artery during early pregnancy.