Early prediction and aspirin for prevention of pre-eclampsia (EPAPP) study: a randomized controlled trial

The optimal dosage of aspirin for preventing preeclampsia in high-risk pregnant women: A network meta-analysis of 23 randomized controlled trials

This study aimed to assess the effectiveness and optimal dosage of aspirin in preventing preeclampsia in high-risk pregnant women. Traditional and network meta-analyses were conducted on data from 23 randomized controlled trials involving 10 547 pregnant women. The findings demonstrated that aspirin significantly reduced the incidence of preeclampsia (OR = 0.66, 95%CI [0.58, 0.75]), with the best preventive effect observed at a dosage of 80-100 mg/day (OR = 0.51, 95%CI [0.36, 0.72]). No significant differences were found in the occurrence of postpartum hemorrhage (OR = 1.03, 95%CI [0.79, 1.33]), small for gestational age (OR = 0.83, 95%CI [0.50, 1.35]), placental abruption (OR = 0.96, 95%CI [0.53, 1.73]), and intrauterine growth restriction (OR = 0.63, 95%CI [0.45, 1.86]) between women taking aspirin and those taking placebos. Different doses of aspirin showed a reduction in preeclampsia incidence, but there was no significant difference in efficacy between the dosage groups. Side effects did not significantly differ between placebo and different aspirin dosage groups. SUCRA analysis suggested that 80-100 mg/day may be the optimal dosage, prioritizing both effectiveness and minimizing side effects. Sensitivity analysis confirmed the robustness of the findings. However, improvements are needed in addressing issues like loss to follow-up, reporting bias, and publication bias. In conclusion, a dosage of 80-100 mg/day is recommended for preventing preeclampsia in high-risk pregnant women, although individual circumstances should be considered for optimizing the balance between effectiveness and safety.

Aspirin at 75 to 81 mg Daily for the Prevention of Preterm Pre-Eclampsia: Systematic Review and Meta-Analysis

Background: Aspirin at 150 mg daily, initiated in the 1st trimester of pregnancy, prevents preterm pre-eclampsia. We aimed to estimate whether a dose of 75 to 81 mg daily can help to prevent preterm pre-eclampsia as well. Methods: A systematic search was conducted using multiple databases and meta-analyses of randomized controlled trials (RCTs) that compared aspirin initiated in the first trimester of pregnancy to placebo or no treatment, following the PRISMA guidelines and the Cochrane risk of bias tool. Results: We retrieved 11 RCTs involving 13,981 participants. Five RCTs had a low risk of bias, one at unclear risk, and fiver had a high risk of bias. A pooled analysis demonstrated that doses of 75 to 81 mg of aspirin, compared to a placebo or no treatment, was not associated with a significant reduction in preterm pre-eclampsia (8 studies; 12,391 participants; relative risk, 0.66; 95% confidence interval: 0.27 to 1.62; p = 0.36), but there was a significant heterogeneity across the studies (I2 = 61%, p = 0.02). Conclusion: It cannot be concluded that taking 75 to 81 mg of aspirin daily reduces the risk of preterm pre-eclampsia. However, given the significant heterogeneity between the studies, the true effect that such a dose of aspirin would have on pregnancy outcomes could not be properly estimated.

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.

A Randomized Controlled Study Comparing the Efficacy of 75mg Versus 150mg Aspirin for the Prevention of Preeclampsia in High-Risk Pregnant Women

Background Preeclampsia is a major factor in both maternal and fetal morbidity and mortality. The most widely investigated preeclampsia prevention medication is low dose Aspirin. However, guidelines differ considerably regarding the prophylactic dose of Aspirin for preeclampsia. Objective The objective is to compare the efficacy of 150mg versus 75mg Aspirin for the prevention of preeclampsia in pregnant women at high risk of preeclampsia. Methodology This was a parallel, open-label, randomized control trial carried over a period of one year and three months at a tertiary care center of Eastern India. Block randomization was done and block sizes of 2 and 4 were used to ensure balanced distributions within the study arms. Primary outcome was the development of preeclampsia and secondary outcomes were fetomaternal complications in both groups. Results The present clinical trial was conducted on 116 pregnant women with a risk factor of preeclampsia and they were randomly assigned to receive either 150mg or 75mg of Aspirin daily beginning from 12 to 16 weeks of gestation till 36 weeks' gestation. A significantly greater number of pregnant females who received Aspirin 75mg (33.92%) developed preeclampsia in contrast to those who received Aspirin 150mg (8.77%), p=0.001, OR = 5.341, 95%CI = 1.829-15.594. There was an insignificant difference in fetomaternal outcome among both the groups of women. Conclusion Among women who are at high risk of developing preeclampsia, Aspirin 150 mg once a day at bedtime is more effective than Aspirin 75 mg once a day at bedtime in preventing preeclampsia with similar fetomaternal outcomes (NICU admission, IUGR, neonatal death, still birth, eclampsia, HELLP syndrome, placental abruption and pulmonary edema).

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 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].

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.

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.

Combined apocyanin and aspirin treatment activates the PI3K/Nrf2/HO-1 signaling pathway and ameliorates preeclampsia symptoms in rats

OBJECTIVE

Pre-eclampsia (PE) is a pregnancy-associated disease characterized by placental dysfunction and increased oxidative stress. Apocyanin is a potent antioxidant and anti-inflammatory which has shown beneficial effects on PE pathogenesis. Aspirin is recognized as the recommendable drug in PE prevention and therapy. Therefore, we aimed to investigate the effects of combining apocyanin and aspirin to treat PE on rat models induced by N-nitro-L-arginine methyl ester (L-NAME) from gestational day (GD) 6 to 16 and elucidate the potential mechanisms.

METHODS

First, female pregnant rats were divided into five different groups: pregnant control, PE, PE + apocyanin, PE + aspirin, and PE + apocyanin + aspirin. Animals received apocyanin (16 mg/kg/day) orally or aspirin by gavage (1.5 mg/kg BM/day) from GD 4 to 16. Blood pressure and urine protein content were monitored every 4 days.

RESULTS

In the PE rat model, elevated systolic blood pressure and proteinuria were ameliorated by the combination of apocyanin and aspirin. Meanwhile, compared with single-dose apocyanin or aspirin, the combined treatment significantly corrected abnormal pregnancy outcomes, decreased sFlt-1 and PlGF, and alleviated oxidative stress both in blood and placental tissues. Moreover, the combined treatment upregulated PI3K, Akt, Nrf2, and HO-1 protein levels in the placental tissues from PE rats.Conclusion: Overall, our results suggested that combined treatment of apocyanin and aspirin ameliorates the PE symptoms compared with single-dose apocyanin or aspirin in a PE rat model. Also, we demonstrated that activating the PI3K/Nrf2/HO-1 pathway can be a valuable therapeutic target to improve the pregnancy outcomes of PE.

Aspirin for the prevention of pre-eclampsia in women with pre-existing diabetes: Systematic review

BACKGROUND

There is a lack of evidence for pre-eclampsia prophylaxis with aspirin in women with pre-existing diabetes mellitus (DM).

AIMS

To examine the evidence for aspirin in pre-eclampsia prophylaxis in women with pre-existing DM.

MATERIAL AND METHODS

An electronic search using Ovid MEDLINE, Embase, CinicalTrials.gov and the Cochrane CENTRAL register of controlled trials through to February 2021 was performed. Reference lists of identified studies, previous review articles, clinical practice guidelines and government reports were manually searched. Randomised controlled trials (RCTs) of aspirin vs placebo for pre-eclampsia prophylaxis were included. Articles were manually reviewed to determine if cohorts included women with DM. The systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Data from included trials were extracted independently by two authors who also independently assessed risk of bias as per the Cochrane Handbook criteria version 5.1.0. Data were analysed using Rev-Man 5.4.

RESULTS

Forty RCTs were identified, of which 11 included a confirmed subset of women with DM; however, data were insufficient for meta-analysis. Meta-analysis of 930 women with DM, from individual patient data included in a systematic review and unpublished data from one of the 11 RCTs, showed a non-significant difference in the outcome of pre-eclampsia in participants treated with aspirin compared to placebo (odds ratio 0.58; 95% CI 0.20-1.71; P = 0.33).

CONCLUSIONS

Pre-eclampsia risk reduction with aspirin prophylaxis in women with pre-existing DM may be similar to women without pre-existing DM. However, randomised data within this meta-analysis were insufficient, warranting the need for further studies within this high-risk group of women.

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.

Dose of aspirin to prevent preterm preeclampsia in women with moderate or high-risk factors: A systematic review and meta-analysis

OBJECTIVE

To evaluate the effect of aspirin dose on the incidence of all gestational age preeclampsia and preterm preeclampsia.

DATA SOURCES

Electronic databases (Cochrane, PubMed, Scopus, ClinicalTrials.gov and the Web of Science) were searched for articles published between January 1985 and March 2019 with no language restrictions.

METHODS

We followed the PRIMSA guidelines and utilized Covidence software. Articles were screened by 2 independent reviewers, with discrepancies settled by an independent 3rd party. Study selection criteria were randomized trials comparing aspirin for prevention of all gestational age and preterm preeclampsia to placebo or no antiplatelet treatment in women aged 15-55 years with moderate or high-risk factors according to the list of risk factors from American College of Obstetricians and Gynecologists and United States Preventive Services Task Force guidelines. The quality of trials was assessed using the Cochrane risk of bias tool. The data were pooled using a random-effects meta-analysis comparing aspirin at doses of <81, 81, 100, and 150 mg. Pre-specified outcomes were all gestational age and preterm preeclampsia.

RESULTS

Of 1,609 articles screened, 23 randomized trials, which included 32,370 women, fulfilled the inclusion criteria. In preterm preeclampsia, women assigned at random to 150 mg experienced a significant 62% reduction in risk of preterm preeclampsia (RR = 0.38; 95% CI: 0.20-0.72; P = 0.011). Aspirin doses <150 mg produced no significant reductions. The number needed to treat with 150 mg of aspirin was 39 (95% CI: 23-100). There was a maximum 30% reduction in risk of all gestational age preeclampsia at all aspirin doses.

CONCLUSIONS

In this meta-analysis, based on indirect comparisons, aspirin at a dose greater than the current, recommended 81 mg was associated with the highest reduction in preterm preeclampsia. Our meta-analysis is limited due to the deficiency of homogeneous high evidence data available in the literature to date; however, it may be prudent for clinicians to consider that the optimal aspirin dose may be higher than the current guidelines advise. Future research to compare the efficacy aspirin doses greater than 81 mg is recommended.

STUDY REGISTRATION

PROSPERO, CRD42019127951 (University of York, UK; http://www.crd.york.ac.uk/PROSPERO/).

Pharmacological Interventions for the Prevention of Fetal Growth Restriction: A Systematic Review and Network Meta-Analysis

The prevention of fetal growth restriction (FGR) is challenging in clinical practice. To date, no meta-analysis summarized evidence on the relative benefits and harms of pharmacological interventions for FGR prevention. We performed a systematic review and network meta-analysis (NetMA), searching PubMed, Embase, Cochrane Library, and ClinicalTrials.gov from inception until November 2019. We included clinical trials and observational studies on singleton gestating women evaluating antiplatelet, anticoagulant, or other treatments, compared between each other or with controls (placebo or no treatment), and considering the pregnancy outcome FGR (primary outcome of the NetMA). Secondary efficacy outcomes included preterm birth, placental abruption, and fetal or neonatal death. Safety outcomes included bleeding and thrombocytopenia. Network meta-analyses using a frequentist framework were conducted to derive odds ratios (ORs) and 95% confidence intervals (CIs). Of 18,780 citations, we included 30 studies on 4,326 patients. Low molecular weight heparin (LMWH), alone or associated with low-dose aspirin (LDA), appeared more efficacious than controls in preventing FGR (OR 2.00, 95% CI 1.27-3.16 and OR 2.67, 95% CI 1.21-5.89 for controls vs. LMWH and LDA + LMWH, respectively). No difference between active treatments emerged in terms of FGR prevention, but estimates for treatments other than LMWH +/- LDA were imprecise. Only the confidence in the evidence regarding LMWH vs. controls was judged as moderate, according to the Confidence in Network Meta-Analysis framework. No treatment was associated with an increased risk of bleeding, although estimates were precise enough only for LMWH. These results should inform clinicians on the benefits of active pharmacological prophylaxis for FGR prevention.

Impact of the ACOG guideline regarding low-dose aspirin for prevention of superimposed preeclampsia in women with chronic hypertension

BACKGROUND

Patients with chronic hypertension are at increased risk for superimposed preeclampsia. The 2016 American College of Obstetricians and Gynecologists guideline recommended initiating 81 mg of daily aspirin for all pregnant women with chronic hypertension to prevent superimposed preeclampsia.

OBJECTIVE

(1) To evaluate the rates of implementation of the 2016 American College of Obstetricians and Gynecologists guideline over time; and (2) to evaluate the effectiveness of aspirin for the prevention of superimposed preeclampsia and other adverse maternal and neonatal outcomes in women with chronic hypertension before and after this guideline.

STUDY DESIGN

This is a retrospective study of women with chronic hypertension who delivered at Thomas Jefferson University Hospital from January 2014 through June 2018. This cohort of women with chronic hypertension was divided into 2 groups, before and after the American College of Obstetricians and Gynecologists recommendation published in September 2016. Daily 81 mg of aspirin was initiated between 12 and 16 weeks. We excluded multiple gestations and incomplete records. The primary outcome was incidence of superimposed preeclampsia, and secondary outcomes were incidence of superimposed preeclampsia with or without severe features, small for gestational age, and preterm birth <37 weeks. Subgroup analysis based on risk stratification was evaluated in women with chronic hypertension requiring antihypertensive medication, history of preeclampsia, and pregestational diabetes.

RESULTS

We identified 457 pregnant women with chronic hypertension, 203 in the post-American College of Obstetricians and Gynecologists group and 254 in the pre-American College of Obstetricians and Gynecologists group. Aspirin 81 mg was offered to 142 (70%) in the post-American College of Obstetricians and Gynecologists group and 18 (7.0%) in the pre-American College of Obstetricians and Gynecologists group. Maternal demographics were not significantly different. The overall incidence of superimposed preeclampsia was not significantly different: 87 (34.3%) vs 72 (35.5%), P=.79, in the pre- and post-American College of Obstetricians and Gynecologists guideline groups, respectively. Superimposed preeclampsia with severe features significantly increased: 32 (12.6%) vs 9 (4.4%), P<.01, whereas superimposed preeclampsia without severe features significantly decreased: 55 (21.7%) vs 63 (31.0%), P=.03. There were no significant differences in small for gestational age neonates or preterm birth <37 weeks incidences between groups. There were no significant differences in the subgroup analysis based on the severity of chronic hypertension requiring antihypertensive medication, history of preeclampsia, or pregestational diabetes.

CONCLUSION

After the adoption of the American College of Obstetricians and Gynecologists guidelines in 70% of the cohort, superimposed preeclampsia, small for gestational age, and preterm birth were not significantly decreased after implementation of aspirin 81 mg initiated between 12 and 16 weeks of gestation.

The effect of aspirin on preeclampsia, intrauterine growth restriction and preterm delivery among healthy pregnancies with a history of preeclampsia

BACKGROUND

Due to the significance of preeclampsia (PE) and its adverse outcomes in the health of both mother and newborn, the present study was carried out to investigate the effect of aspirin on preventing the occurrence of PE, intrauterine growth restriction (IUGR), and preterm delivery in women with a previous history of PE.

METHODS

The present clinical trial was conducted on 90 pregnant women with a previous history of PE referred to the Khalij Fars Hospital in Bandar Abbas, Hormozgan Province Iran from April 2017 to August 2018. The subjects of the study were randomly assigned into two groups of intervention and control to receive either 80 mg of aspirin or placebo daily during the pregnancy. Patients' information was obtained and recorded upon entering the study, follow-up visits, and childbirth.

RESULTS

Among participants who entered the clinical trial, 86 patients (95.6%) completed the study. During the pregnancy, systolic blood pressure increased by 8.25 ± 14.83 and 19.06 ± 18.33 mmHg in aspirin and placebo groups, respectively (p = 0.001). Also, the same happened with diastolic blood pressure (6.12 ± 11.46 vs 13.48 ± 13.95 mmHg, p = 0.010). The rate of PE was equal to 27 (62.8%) and 38 (88.4%) in the aspirin and placebo groups, respectively (aOR = 0.23, p = 0.013). In the aspirin group, the rate of IUGR was equal to 27.9% compared with 25.6% of newborns in the control group (aOR = 1.18, p = 0.750). Similarly, there was no significant difference in the rate of preterm delivery between the two groups (p = 0.061).

CONCLUSION

The findings of the present study conducted exclusively on women with previous documented PE revealed that taking aspirin may have a preventive effect on PE in the current pregnancy.

Prophylactic aspirin for preventing pre-eclampsia and its complications: An overview of meta-analyses

Benefits of aspirin administration on pre-eclampsia and IUGR depend on the gestational age and dose of aspirin administration. Meta-analyses show that, to prevent preterm labor, aspirin could be administrated even after 16 weeks of gestational age.

The Role of Microbiomes in Pregnant Women and Offspring: Research Progress of Recent Years

Pregnancy is a complicated and delicate process, the maternal body undergoes changes on hormones, immunity, and metabolism during pregnancy to support fetal development. Microbiomes in the human body mainly live in the intestine, and the human gut microbiomes are complex, which composed of more than 500 to 1500 different bacteria, archaea, fungi, and viruses. Studies have shown that these microbiomes are not only involved in the digestion and absorption of food but also indispensable in regulating host health. In recent years, there has been increasing evidence that microbiomes are important for pregnant women and fetuses. During pregnancy, there will be great changes in gut microbiomes. Regulating gut microbiomes is beneficial to the health of the mother and the fetus. In addition, many complications during pregnancy are related to gut microbiomes, such as gestational diabetes, obesity, preeclampsia, digestive disorders, and autoimmune diseases. Moreover, the microbiomes in mother's milk and vagina are closely related to the colonization of microbiomes in the early life of infants. In this review, we systematically review the role of maternal microbiomes in different gestational complications, and elucidate the function and mechanism of maternal microbiomes in the neural development and immune system of offspring. These will provide a clear knowledge framework or potential research direction for researchers in related fields.

The need for implementation of first trimester screening for preeclampsia and fetal growth restriction in low resource settings

Background: Preeclampsia [PE] and fetal growth restriction [FGR] is a major cause of perinatal morbidity in both developed and developing countries but the disease leaves a severe impact in developing countries, due to the late presentation of cases where prevention and treatment becomes impossible. Routine antenatal ultrasound and health checkups in periphery are usually done in first trimester for dating and viability scan, in midtrimester for anomaly scan and in third trimester for safe confinement. Underlying disorder of deep placentation which is unidentified can lead to increased maternal morbidity and fetal compromise between 26 to 34 weeks of gestation The complications present at an irreversible stage where there is no sufficient time even for referral to tertiary care center. Frequent antenatal visits as suggested by WHO would definitely bring down maternal mortality but this increased surveillance when offered to all might be a huge burden to health care providers in low resource settings. An acceptable screening test should help in triaging the high risk group in first trimester itself targeting about only one third of the population for prophylactic therapy and increased antenatal surveillance.The objective of this study is to evaluate the performance and feasibility of different screening protocols in low resource settings.Methodology: Screening for PE and FGR was done at the 11-14 weeks aneuploidy scan as per FMF guidelines. Group I included 6289 women whose risk prediction was done with maternal characteristics [MC], mean arterial pressure [MAP] and Uterine artery Doppler [UAD]. Group II included 2067 women whose risk was predicted with MC, MAP, UAD and PAPP-A. Group III included 576 women whose risk prediction included all parameters with PLGF.Results: Two thousand five hundred fifty-seven cases were screen positive in group I and 602 were screen positive in group II. In group III which included PLGF, 24 were positive for early onset PE and 36 for late onset PE. The number needed to treat [NNT] was 35.9, 29.1 and 10% in Group I, II and III respectively. The detection rate [DR] for PE and FGR was 60% in Group I and DR for FGR in Group II was 85%. In Group III, for early onset PE the DR was 98% and 68% for late onset PE.Conclusion: Screening for PE with available resources in the periphery needs to be implemented to avoid its grave complications. Traditional screening for PE by NICE guidelines can be adopted but may have a detection rate of only 30-40%. Though screening by ACOG criteria may have good detection rates but more than two thirds of the population would become screen positive which nullifies this approach as a good screening methodology in low resource settings. Multiparametric approach for screening in first trimester serves as a better screening tool to enable higher detection rate of disease with least false positive rates. Uterine artery Doppler when combined with maternal characteristics and mean arterial pressure could achieve a detection rate of about 60% and would still target only one third of the population for increased antenatal surveillance. This requires training healthcare professionals in the periphery for this approach and this should be our prime focus in the current scenario. Inclusion of serum biochemistry would still bring down the target population to 10% and increase the DR and can be considered as an additional test in economically feasible population. In low resource settings a better screening approach to PE would be a combination of maternal history, biophysical or biochemical parameters whichever is feasible considering the economy and availability of resources.

Cross-Talk between Oxidative Stress and Inflammation in Preeclampsia

The occurrence of hypertensive syndromes during pregnancy leads to high rates of maternal-fetal morbidity and mortality. Amongst them, preeclampsia (PE) is one of the most common. This review aims to describe the relationship between oxidative stress and inflammation in PE, aiming to reinforce its importance in the context of the disease and to discuss perspectives on clinical and nutritional treatment, in this line of research. Despite the still incomplete understanding of the pathophysiology of PE, it is well accepted that there are placental changes in pregnancy, associated with an imbalance between the production of reactive oxygen species and the antioxidant defence system, characterizing the placental oxidative stress that leads to an increase in the production of proinflammatory cytokines. Hence, a generalized inflammatory process occurs, besides the presence of progressive vascular endothelial damage, leading to the dysfunction of the placenta. There is no consensus in the literature on the best strategies for prevention and treatment of the disease, especially for the control of oxidative stress and inflammation. In view of the above, it is evident the important connection between oxidative stress and inflammatory process in the pathogenesis of PE, being that this disease is capable of causing serious implications on both maternal and fetal health. Reports on the use of anti-inflammatory and antioxidant compounds are analysed and still considered controversial. As such, the field is open for new basic and clinical research, aiming the development of innovative therapeutic approaches to prevent and to treat PE.

Antiplatelet agents for preventing pre-eclampsia and its complications

BACKGROUND

Pre-eclampsia is associated with deficient intravascular production of prostacyclin, a vasodilator, and excessive production of thromboxane, a vasoconstrictor and stimulant of platelet aggregation. These observations led to the hypotheses that antiplatelet agents, low-dose aspirin in particular, might prevent or delay development of pre-eclampsia.

OBJECTIVES

To assess the effectiveness and safety of antiplatelet agents, such as aspirin and dipyridamole, when given to women at risk of developing pre-eclampsia.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (30 March 2018), and reference lists of retrieved studies. We updated the search in September 2019 and added the results to the awaiting classification section of the review.

SELECTION CRITERIA

All randomised trials comparing antiplatelet agents with either placebo or no antiplatelet agent were included. Studies only published in abstract format were eligible for inclusion if sufficient information was available. We would have included cluster-randomised trials in the analyses along with individually-randomised trials, if any had been identified in our search strategy. Quasi-random studies were excluded. Participants were pregnant women at risk of developing pre-eclampsia. Interventions were administration of an antiplatelet agent (such as low-dose aspirin or dipyridamole), comparisons were either placebo or no antiplatelet.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trials for inclusion and extracted data independently. For binary outcomes, we calculated risk ratio (RR) and its 95% confidence interval (CI), on an intention-to-treat basis. For this update we incorporated individual participant data (IPD) from trials with this available, alongside aggregate data (AD) from trials where it was not, in order to enable reliable subgroup analyses and inclusion of two key new outcomes. We assessed risk of bias for included studies and created a 'Summary of findings' table using GRADE.

MAIN RESULTS

Seventy-seven trials (40,249 women, and their babies) were included, although three trials (relating to 233 women) did not contribute data to the meta-analysis. Nine of the trials contributing data were large (> 1000 women recruited), accounting for 80% of women recruited. Although the trials took place in a wide range of countries, all of the nine large trials involved only women in high-income and/or upper middle-income countries. IPD were available for 36 trials (34,514 women), including all but one of the large trials. Low-dose aspirin alone was the intervention in all the large trials, and most trials overall. Dose in the large trials was 50 mg (1 trial, 1106 women), 60 mg (5 trials, 22,322 women), 75mg (1 trial, 3697 women) 100 mg (1 trial, 3294 women) and 150 mg (1 trial, 1776 women). Most studies were either low risk of bias or unclear risk of bias; and the large trials were all low risk of bas. Antiplatelet agents versus placebo/no treatment The use of antiplatelet agents reduced the risk of proteinuric pre-eclampsia by 18% (36,716 women, 60 trials, RR 0.82, 95% CI 0.77 to 0.88; high-quality evidence), number needed to treat for one women to benefit (NNTB) 61 (95% CI 45 to 92). There was a small (9%) reduction in the RR for preterm birth <37 weeks (35,212 women, 47 trials; RR 0.91, 95% CI 0.87 to 0.95, high-quality evidence), NNTB 61 (95% CI 42 to 114), and a 14% reduction infetal deaths, neonatal deaths or death before hospital discharge (35,391 babies, 52 trials; RR 0.85, 95% CI 0.76 to 0.95; high-quality evidence), NNTB 197 (95% CI 115 to 681). Antiplatelet agents slightly reduced the risk of small-for-gestational age babies (35,761 babies, 50 trials; RR 0.84, 95% CI 0.76 to 0.92; high-quality evidence), NNTB 146 (95% CI 90 to 386), and pregnancies with serious adverse outcome (a composite outcome including maternal death, baby death, pre-eclampsia, small-for-gestational age, and preterm birth) (RR 0.90, 95% CI 0.85 to 0.96; 17,382 women; 13 trials, high-quality evidence), NNTB 54 (95% CI 34 to 132). Antiplatelet agents probably slightly increase postpartum haemorrhage > 500 mL (23,769 women, 19 trials; RR 1.06, 95% CI 1.00 to 1.12; moderate-quality evidence due to clinical heterogeneity), and they probably marginally increase the risk of placental abruption, although for this outcome the evidence was downgraded due to a wide confidence interval including the possibility of no effect (30,775 women; 29 trials; RR 1.21, 95% CI 0.95 to 1.54; moderate-quality evidence). Data from two large trials which assessed children at aged 18 months (including results from over 5000 children), did not identify clear differences in development between the two groups.

AUTHORS' CONCLUSIONS

Administering low-dose aspirin to pregnant women led to small-to-moderate benefits, including reductions in pre-eclampsia (16 fewer per 1000 women treated), preterm birth (16 fewer per 1000 treated), the baby being born small-for-gestational age (seven fewer per 1000 treated) and fetal or neonatal death (five fewer per 1000 treated). Overall, administering antiplatelet agents to 1000 women led to 20 fewer pregnancies with serious adverse outcomes. The quality of evidence for all these outcomes was high. Aspirin probably slightly increased the risk of postpartum haemorrhage of more than 500 mL, however, the quality of evidence for this outcome was downgraded to moderate, due to concerns of clinical heterogeneity in measurements of blood loss. Antiplatelet agents probably marginally increase placental abruption, but the quality of the evidence was downgraded to moderate due to low event numbers and thus wide 95% CI. Overall, antiplatelet agents improved outcomes, and at these doses appear to be safe. Identifying women who are most likely to respond to low-dose aspirin would improve targeting of treatment. As almost all the women in this review were recruited to the trials after 12 weeks' gestation, it is unclear whether starting treatment before 12 weeks' would have additional benefits without any increase in adverse effects. While there was some indication that higher doses of aspirin would be more effective, further studies would be warranted to examine this.

Ameliorative effects of pre-eclampsia by quercetin supplement to aspirin in a rat model induced by L-NAME

As an inflammatory disease, pre-eclampsia is correlated with elevation of pro-inflammatory cytokines and maternal endothelial dysfunction. Aspirin plays an important role in the prevention and therapy of pre-eclampsia. Quercetin is a bioflavonoid which has anti-oxidant and reno-protective abilities. We aimed to figure out the effects of quercetin supplement to aspirin on the therapy against pre-eclampsia. Female pregnant Sprague-Dawley rats were divided into five groups according to the drug treatment. Aspirin [1.5 mg/kg body weight (BW)] or quercetin (2 mg/kg BW) treatment was administered from gestational day (GD) 4 to GD19. Rat model of pre-eclampsia was induced by NG-nitro-Larginine-methyl-ester (L-NAME). In pre-eclampsia rats induced by L-NAME, systolic blood pressures (SBP), proteinuria, malonyldialdehyde (MDA), and inflammatory cytokines levels were decreased by the treatment of quercetin supplement to aspirin. In the uterus, quercetin supplement to aspirin prevented the expression of VEGF and sFlt-1 mRNA. The treatment of quercetin supplement to aspirin rescued the declined survival rate and weight of pups caused by L-NAME-induced pre-eclampsia. Based on our study, compared with the treatment of aspirin alone, quercetin supplement to aspirin enhanced the therapeutic effects of aspirin on pre-eclampsia rats induced by L-NAME.

First-trimester and combined first- and second-trimester prediction of small-for-gestational age and late fetal growth restriction

OBJECTIVE

To develop a first-trimester or combined first- and second-trimester screening algorithm for the prediction of small-for-gestational age (SGA) and late fetal growth restriction (FGR).

METHODS

This was a retrospective study of women with singleton pregnancy, who underwent routine first-, second- and third-trimester ultrasound assessment. Late FGR was defined, at ≥ 32 weeks' gestation in the absence of congenital anomalies, as either (i) estimated fetal weight (EFW) or birth weight (BW) < 3^rd centile, or (ii) EFW < 10^th centile and either uterine artery mean pulsatility index (UtA-PI) > 95^th centile or cerebroplacental ratio (CPR) < 5^th centile. Neonates with BW < 10^th centile, regardless of prenatal parameters, were defined as SGA. The predictive effectiveness of maternal and first- and second-trimester factors was tested using logistic regression and receiver-operating characteristics curve analyses.

RESULTS

A total of 3520 fetuses were included (late FGR, n = 109 (3.1%); SGA, n = 292 (8.3%)). Of the late FGR cases, 56 (1.6%) fulfilled the antenatal criteria (EFW < 3^rd centile or EFW < 10^th centile plus abnormal UtA-PI or CPR) and were defined as prenatally detected late FGR. A first-trimester screening model (comprising conception method, smoking status, maternal height, pregnancy-associated plasma protein-A (PAPP-A) and UtA-PI) could predict 50.0% of the prenatally diagnosed and 36.7% of the overall late FGR fetuses for a 10% false-positive rate (FPR). A model combining first- and second-trimester screening parameters (conception method, smoking status, PAPP-A, second- trimester EFW, head circumference/abdominal circumference ratio and UtA-PI) could predict 78.6% of the prenatally detected, and 59.6% of the overall late FGR fetuses, for a 10% FPR (area under the curve 0.901 (95% CI, 0.856-0.947) and 0.855 (95% CI, 0.818-0.891), respectively). The prediction of SGA was suboptimal for both first-trimester and combined screening.

CONCLUSIONS

A simple model combining maternal and first- and second-trimester predictors can detect 60% of fetuses that will develop late FGR, and 79% of those fetuses that will be classified prenatally as late FGR, for a 10% FPR. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Low-dose aspirin in the prevention of pre-eclampsia in China (APPEC study): protocol for a multicentre randomized controlled trial

BACKGROUND

Low-dose aspirin (LDA) has been proposed as a safe and inexpensive prophylactic agent. Studies in European/Western populations have shown promising results indicating that LDA can reduce the occurrence of pre-eclampsia (PE) in women with identifiable risk factors. However, few controlled trials, particularly large randomized controlled trials, have been performed in Asian populations. The aim of this project is to evaluate the effect of LDA for PE prevention on high-risk pregnant women in China, where PE is highly prevalent and the LDA supply status is commonly suboptimal.

METHODS/DESIGN

An open-label, multicentre randomized controlled trial is being conducted at 13 tertiary hospitals in 11 provinces in China. A total of 1000 eligible women with high-risk factors for developing PE according to their medical histories are being randomized into two groups: a control group (n = 500) and an intervention group (n = 500). Women with high-risk factors, such as a history of PE, chronic hypertension, type 1 or 2 diabetes, advanced maternal age, obesity, family history of PE or nulliparity are eligible. The control group is advised to undergo routine examinations, whereas the intervention group undergoes the routine examinations and receives LDA. LDA (100 mg/d) should be prescribed at night, initiating from early pregnancy (12-20 weeks of gestation) and lasting until 34 weeks of gestation. Demographic data and clinical endpoint outcomes, as well as biological samples (e.g., maternal blood, cord blood, amniotic fluid and placental samples), will be collected. The primary outcome is the occurrence of PE, and the secondary outcomes include maternal and neonatal outcomes and maternal biomarker levels.

DISCUSSION

This is the first and largest multicentre randomized controlled trial to assess the effect of LDA in preventing PE in a Chinese population. The results will potentially influence the prenatal care recommendations in China regarding intervention with LDA for PE.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02797249 . Registered on 7 June 2016.

Aspirin for the prevention of preterm and term preeclampsia: systematic review and metaanalysis

OBJECTIVE DATA

Metaanalyses of randomized controlled trials have reported contradictory results about the effect of aspirin in the prevention of preeclampsia, both in terms of the gestational age at the onset of treatment and the dose of the drug. The controversy may be resolved by a metaanalysis that includes several recently published trials and particularly the large Combined Multimarker Screening and Randomized Patient Treatment with Aspirin for Evidence-based Preeclampsia Prevention trial and by examination of whether there is a difference of the effect of aspirin on preterm vs term preeclampsia.

STUDY

We performed a systematic review and metaanalysis that evaluated the prophylactic effect of aspirin during pregnancy.

STUDY APPRAISAL AND SYNTHESIS METHODS

We completed a literature search through PubMed, Cinhal, Embase, Web of Science, and Cochrane library from 1985 to June 2017. Relative risks with random effect were calculated with their 95% confidence intervals.

RESULTS

Sixteen trials that included 18,907 participants provided data for preterm and term preeclampsia. Eight of the included studies were evaluated as being of good quality, and the other 8 studies were deemed to be of poor or uncertain quality. There was high heterogeneity within studies (I2 >50%) for preterm and term preeclampsia, but no heterogeneity was found in the subgroup of preterm preeclampsia when the onset of treatment was ≤16 weeks of gestation and the daily dose of aspirin was ≥100 mg (I2=0%). Administration of aspirin was associated with reduction in the risk of preterm preeclampsia (relative risk, 0.62; 95% confidence interval, 0.45-0.87), but there was no significant effect on term preeclampsia (relative risk, 0.92; 95% confidence interval, 0.70-1.21). The reduction in preterm preeclampsia was confined to the subgroup in which aspirin was initiated at ≤16 weeks of gestation and at a daily dose of ≥100 mg (relative risk, 0.33; 95% confidence interval, 0.19-0.57). This effect was also observed in the high-quality studies. The reduction in preterm preeclampsia that was observed in the largest trial (Combined Multimarker Screening and Randomized Patient Treatment with Aspirin for Evidence-based Preeclampsia Prevention; n=1620; relative risk, 0.38; 95% confidence interval, 0.20-0.72) was similar to that in the 5 smaller trials in which aspirin was initiated at ≤16 weeks of gestation and at a daily dose of ≥100 mg (n=639; relative risk, 0.22; 95% confidence interval, 0.07-0.66).

CONCLUSION

Aspirin reduces the risk of preterm preeclampsia, but not term preeclampsia, and only when it is initiated at ≤16 weeks of gestation and at a daily dose of ≥100 mg.

Prediction and prevention of pre-eclampsia in Asian subpopulation

The benefit of the early administration of aspirin to reduce preterm pre-eclampsia among screened positive European women from multivariate algorithmic approach (ASPRE trial) has opened an intense debate on the feasibility of universal screening. This review aims to assess the new perspectives in the combined screening of pre-eclampsia in the first trimester of pregnancy and the chances for prevention using low-dose aspirin with special emphasis on the particularities of the Asian population. PubMed, CENTRAL and Embase databases were searched from inception until 15 November 2017 using combinations of the search terms: preeclampsia, Asian, prenatal screening, early prediction, ultrasonography, pregnancy, biomarker, mean arterial pressure, soluble fms-like tyrosine kinase-1, placental growth factor, pregnancy-associated plasma protein-A and pulsatility index. This is not a systematic review or meta-analysis, so the risk of bias of the selected published articles and heterogeneity among the studies need to be considered. The prevalence of pre-eclampsia and serum levels of biochemical markers in Asian are different from Caucasian women; hence, Asian ethnicity needs to be corrected for in the algorithmic assessment of multiple variables to improve the screening performance. Aspirin prophylaxis may still be viable in Asian women, but resource implication needs to be considered. Asian ethnicity should be taken into account before implementing pre-eclampsia screening strategies in the region. The variables included can be mixed and matched to achieve an optimal performance that is appropriate for economical restriction in individual countries.

Molecular and cellular underpinnings of normal and abnormal human placental blood flows

Abnormal placental function is well-established as a major cause for poor pregnancy outcome. Placental blood flow within the maternal uteroplacental compartment, the fetoplacental circulation or both is a vital factor in mediating placental function. Impairment in flow in either or both vasculatures is a significant risk factor for adverse pregnancy outcome, potentially impacting maternal well-being, affecting immediate neonatal health and even influencing the long-term health of the infant. Much remains unknown regarding the mechanistic underpinnings of proper placental blood flow. This review highlights the currently recognized molecular and cellular mechanisms in the development of normal uteroplacental and fetoplacental blood flows. Utilizing the entities of preeclampsia and fetal growth restriction as clinical phenotypes that are often evident downstream of abnormal placental blood flow, mechanisms underlying impaired uteroplacental and fetoplacental blood flows are also discussed. Deficiencies in knowledge, which limit the efficacy of clinical care, are also highlighted, underscoring the need for continued research on normal and abnormal placental blood flows.

Aspirin vs Heparin for the Prevention of Preeclampsia

Preeclampsia is a hypertensive disorder of pregnancy that remains a significant cause of maternal morbidity and mortality worldwide. Preeclampsia can be resolved by delivery, and most of the proposed preventive treatment approaches are based on processes involved in placental development in early pregnancy. Yet, none of these has been established in clinical practice. Low-dose aspirin is the most promising candidate, nevertheless; while some individual randomized controlled trials showed minimal or no statistically significant benefit, recent metanalyses showed that early initiation before 16 weeks of gestation is associated with prevention of early-onset preeclampsia and reduction in prevalence of perinatal death or morbidity of pregnant women. Heparin could be an alternative antithrombotic and anti-inflammatory median to prevent preeclampsia either alone or in combination with aspirin; however, results are conflicting concerning efficacy.

Impact of aspirin on trophoblastic invasion in women with abnormal uterine artery Doppler at 11-14 weeks: a randomized controlled study

OBJECTIVE

Defective trophoblastic invasion is a key feature in many cases of pre-eclampsia (PE). Uterine artery (UtA) Doppler is a validated non-invasive proxy for trophoblastic invasion. The aim of this study was to explore whether low-dose aspirin, administered from the first trimester, improves trophoblastic invasion, evaluated by UtA Doppler during the second and third trimesters in women defined as high risk by abnormal first-trimester UtA Doppler.

METHODS

This randomized Phase-II study had a triple-blind, parallel-arm, controlled design. Singleton pregnancies with abnormal mean UtA Doppler at 11-14 weeks and absence of other major risk factors for PE received 150 mg extended-release aspirin or identical-appearing placebo tablets from study inclusion to 28 weeks. Main outcome measure was UtA pulsatility index (PI) at 28 weeks' gestation. Secondary outcomes included frequency of development of PE and growth restriction/small-for-gestational age (SGA).

RESULTS

A total of 155 women completed the follow-up and were analyzed. No difference in mean UtA-PI was found between women in the aspirin and placebo groups at 28 weeks (mean UtA-PI Z-score (mean ± SD), 0.99 ± 1.48 vs 0.85 ± 1.25; P = 0.52). Seven women developed PE: four (5%) in the aspirin group and three (4%) in the placebo group. There was a trend toward lower incidence of SGA in the aspirin group (8.8% vs 17.3%; P = 0.11).

CONCLUSION

In women with defective trophoblastic invasion, as reflected by abnormal UtA Doppler, low-dose aspirin started in the first trimester does not have a significant effect on UtA impedance as pregnancy progresses; however, the study was underpowered to detect potential small effects . Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

The role of aspirin dose on the prevention of preeclampsia and fetal growth restriction: systematic review and meta-analysis

BACKGROUND

Preeclampsia and fetal growth restriction are major causes of perinatal death and handicap in survivors. Randomized clinical trials have reported that the risk of preeclampsia, severe preeclampsia, and fetal growth restriction can be reduced by the prophylactic use of aspirin in high-risk women, but the appropriate dose of the drug to achieve this objective is not certain.

OBJECTIVE

We sought to estimate the impact of aspirin dosage on the prevention of preeclampsia, severe preeclampsia, and fetal growth restriction.

STUDY DESIGN

We performed a systematic review and meta-analysis of randomized controlled trials comparing the effect of daily aspirin or placebo (or no treatment) during pregnancy. We searched MEDLINE, Embase, Web of Science, and Cochrane Central Register of Controlled Trials up to December 2015, and study bibliographies were reviewed. Authors were contacted to obtain additional data when needed. Relative risks for preeclampsia, severe preeclampsia, and fetal growth restriction were calculated with 95% confidence intervals using random-effect models. Dose-response effect was evaluated using meta-regression and reported as adjusted R². Analyses were stratified according to gestational age at initiation of aspirin (≤16 and >16 weeks) and repeated after exclusion of studies at high risk of biases.

RESULTS

In all, 45 randomized controlled trials included a total of 20,909 pregnant women randomized to between 50-150 mg of aspirin daily. When aspirin was initiated at ≤16 weeks, there was a significant reduction and a dose-response effect for the prevention of preeclampsia (relative risk, 0.57; 95% confidence interval, 0.43-0.75; P < .001; R², 44%; P = .036), severe preeclampsia (relative risk, 0.47; 95% confidence interval, 0.26-0.83; P = .009; R², 100%; P = .008), and fetal growth restriction (relative risk, 0.56; 95% confidence interval, 0.44-0.70; P < .001; R², 100%; P = .044) with higher dosages of aspirin being associated with greater reduction of the 3 outcomes. Similar results were observed after the exclusion of studies at high risk of biases. When aspirin was initiated at >16 weeks, there was a smaller reduction of preeclampsia (relative risk, 0.81; 95% confidence interval, 0.66-0.99; P = .04) without relationship with aspirin dosage (R², 0%; P = .941). Aspirin initiated at >16 weeks was not associated with a risk reduction or a dose-response effect for severe preeclampsia (relative risk, 0.85; 95% confidence interval, 0.64-1.14; P = .28; R², 0%; P = .838) and fetal growth restriction (relative risk, 0.95; 95% confidence interval, 0.86-1.05; P = .34; R², not available; P = .563).

CONCLUSION

Prevention of preeclampsia and fetal growth restriction using aspirin in early pregnancy is associated with a dose-response effect. Low-dose aspirin initiated at >16 weeks' gestation has a modest or no impact on the risk of preeclampsia, severe preeclampsia, and fetal growth restriction. Women at high risk for those outcomes should be identified in early pregnancy.

Ischemic placental syndrome--prediction and new disease monitoring

The last decade has seen an improved understanding of the cause of the development of pathologies such as gestational hypertension, preeclampsia, intrauterine growth restriction, intrauterine fetal death or placental abruption. Nowadays, we know that most conditions within this group share the same pathogenesis, the cause of which is placental ischemia. The following review is an attempt to propose a new method for prediction, diagnosis and--above all--appropriate monitoring of pregnant women and fetuses developing the ischemic placental syndrome with the use of tests that are new but yet widely available in clinical diagnosis. They are closely related to the condition's pathogenesis, therefore their elevated levels may predate clinical symptoms, and--most importantly--they correlate with syndrome aggravation and the occurrence of complications. Perhaps, the new look will allow us to improve perinatal results by reducing mortality and severe complications in pregnant women and fetal deaths resulting from sudden intrauterine fetal death or placental abruption.