Aspirin (100 mg) used for prevention of pre-eclampsia in nulliparous women: the Essai Régional Aspirine Mère-Enfant study (Part 1)

First trimester screening for pre-eclampsia and targeted aspirin prophylaxis: a cost-effectiveness cohort study

OBJECTIVE

Investigate cost-effectiveness of first trimester pre-eclampsia screening using the Fetal Medicine Foundation (FMF) algorithm and targeted aspirin prophylaxis in comparison with standard care.

DESIGN

Retrospective observational study.

SETTING

London tertiary hospital.

POPULATION

5957 pregnancies screened for pre-eclampsia using the National Institute for Health and Care Excellence (NICE) method.

METHODS

Differences in pregnancy outcomes between those who developed pre-eclampsia, term pre-eclampsia and preterm pre-eclampsia were compared by the Kruskal-Wallis and Chi-square tests. The FMF algorithm was applied retrospectively to the cohort. A decision analytic model was used to estimate costs and outcomes for pregnancies screened using NICE and those screened using the FMF algorithm. The decision point probabilities were calculated using the included cohort.

MAIN OUTCOME MEASURES

Incremental healthcare costs and QALY gained per pregnancy screened.

RESULTS

Of 5957 pregnancies, 12.8% and 15.9% were screen-positive for development of pre-eclampsia using the NICE and FMF methods, respectively. Of those who were screen-positive by NICE recommendations, aspirin was not prescribed in 25%. Across the three groups, namely, pregnancies without pre-eclampsia, term pre-eclampsia and preterm pre-eclampsia there was a statistically significant trend in rates of emergency caesarean (respectively 21%, 43% and 71.4%; P < 0.001), admission to neonatal intensive care unit (NICU) (5.9%, 9.4%, 41%; P < 0.001) and length of stay in NICU. The FMF algorithm was associated with seven fewer cases of preterm pre-eclampsia, cost saving of £9.06 and QALY gain of 0.00006/pregnancy screened.

CONCLUSIONS

Using a conservative approach, application of the FMF algorithm achieved clinical benefit and an economic cost saving.

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.

Aspirin delays the onset of hypertensive disorders of pregnancy among nulliparous pregnant women: A secondary analysis of the ASPIRIN trial

OBJECTIVE

To assess the impact of low-dose aspirin (LDA) starting in early pregnancy on delaying preterm hypertensive disorders of pregnancy.

DESIGN

Non-prespecified secondary analysis of a randomised masked trial of LDA.

SETTING

The study was conducted among women in the Global Network for Women's and Children's Health's Maternal and Newborn Health Registry (MNHR) clusters, a prospective, population-based study in Kenya, Zambia, the Democratic Republic of the Congo (DRC), Pakistan, India (two sites-Belagavi and Nagpur) and Guatemala.

POPULATION

Nulliparous singleton pregnancies between 6+0 weeks and 13+6  weeks in six low-middle income countries (Democratic Republic of Congo, Guatemala, India, Kenya, Pakistan, Zambia) enrolled in the ASPIRIN Trial.

METHODS

We compared the incidence of HDP at delivery at three gestational age periods (<28, <34 and <37 weeks) between women who were randomised to aspirin or placebo. Women were included if they were randomised and had an outcome at or beyond 20 weeks (Modified Intent to Treat).

MAIN OUTCOME MEASURES

Our primary outcome was pregnancies with HDP associated with preterm delivery (HDP@delivery) before <28, <34 and <37 weeks. Secondary outcomes included small for gestational age (SGA) <10th percentile, <5th percentile, and perinatal mortality.

RESULTS

Among the 11 976 pregnancies, LDA did not significantly lower HDP@delivery <28 weeks (relative risk [RR] 0.18, 95% confidence interval [CI] 0.02-1.52); however, it did lower HDP@delivery <34 weeks (RR 0.37, 95% CI 0.17-0.81) and HDP@delivery <37 weeks (RR 0.66, 95% CI 0.49-0.90). The overall rate of HDP did not differ between the two groups (RR 1.08, 95% CI 0.94-1.25). Among those pregnancies who had HDP, SGA <10th percentile was reduced (RR 0.81, 95% CI 0.67-0.99), though SGA <5th percentile was not (RR 0.84, 95% CI 0.64-1.09). Similarly, perinatal mortality among pregnancies with HDP occurred less frequently (RR 0.55, 95% CI 0.33-0.92) in those receiving LDA. Pregnancies randomised to LDA delivered later with HDP compared with those receiving placebo (median gestational age 38.5 weeks vs. 37.9 weeks; p = 0.022).

CONCLUSIONS

In this secondary analysis of a study of low-risk nulliparous singleton pregnancies, early administration of LDA resulted in lower rates of preterm HDP and delivery before 34 and 37 weeks but not in the overall rate of HDP. These results suggest that LDA works in part by delaying HDP.

The great obstetrical syndromes and the placenta

Although historically pre-eclampsia, preterm birth, abruption, fetal growth restriction and stillbirth have been viewed as clinically distinct entities, a growing body of literature has demonstrated that the placenta and its development is the root cause of many cases of these conditions. This has led to the term 'the great obstetrical syndromes' being coined to reflect this common origin. Although these conditions mostly manifest in the second half of pregnancy, a failure to complete deep placentation (the transition from histiotrophic placentation to haemochorial placenta at 10-18 weeks of gestation via a second wave of extravillous trophoblast invasion), is understood to be key to the pathogenesis of the great obstetrical syndromes. While the reasons that the placenta fails to achieve deep placentation remain active areas of investigation, maternal inflammation and thrombosis have been clearly implicated. From a clinical standpoint these mechanisms provide a biological explanation of how low-dose aspirin, which affects the COX-1 receptor (thrombosis) and the COX-2 receptor (inflammation), prevents not just pre-eclampsia but all the components of the great obstetrical syndromes if initiated early in pregnancy. The optimal dose of low-dose aspirin that is maximally effective in pregnancy remains a question open for further research. Additionally, other candidate medications have been identified that may also prevent pre-eclampsia, and further study of them may offer therapeutic options beyond low-dose aspirin. Interestingly, three of the eight identified compounds (hydroxychloroquine, metformin and pravastatin) are known to decrease inflammation.

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.

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..

[Use of aspirin 100 mg / day to prevent Preeclampsia, in high risk pregnancies, in a cohort from Argentina]

Objectives

The objective of the present study was to analyse the use of 100 g aspirin dose as prevention method for preeclampsia in high risk pregnant patients.

Methods

A retrospective cohort study was performed in high risk pregnant patients with a blood pressure protocol, and the use of 100 mg of aspirin vs. its non-use was evaluated in the incidence of PREEC. Estimations between the two groups were performed with and without variable adjustment by means of binary logistic regression models.

Results

633 high risk pregnant patients were evaluated. The average age was 30±7 years old, and 25±8 weeks of pregnancy. 281 women (44.3 %) within this group received aspirin. The total prevalence of PREEC in our sample was 151 pregnant women (23.8 %). Pregnant patients under the aspirin treatment developed less PREEC events (19.2% vs 27.5%, p=0.019); with OR not adjusted 0.62 (IC95% 0.43-0.91 p= 0.017). The risk was similar when it was adjusted by age, preeclampsia history, diabetes mellitus and chronic high blood pressure. (OR adjusted 0.63 IC95% 0.43-0.92 p= 0.017).

Conclusions

The use of 100 mg of aspirin a day before the 20th week of pregnancy in high risk pregnant patients decreased the risk of developing PREEC, regardless the age and risk factors.

Cost-effectiveness analysis of a model of first-trimester prediction and prevention of preterm pre-eclampsia compared with usual care

OBJECTIVES

Pre-eclampsia (PE) causes substantial maternal and neonatal mortality and morbidity. In addition to the personal impact on women, children and their families, PE has a significant economic impact on our society. Recent research suggests that a first-trimester multivariate model is highly predictive of preterm (< 37 weeks' gestation) PE and can be combined successfully with targeted prophylaxis (low-dose aspirin), resulting in an 80% reduction in prevalence of disease. The aim of this study was to examine the potential health outcomes and cost implications following introduction of first-trimester prediction and prevention of preterm PE within a public healthcare setting, compared with usual care, and to conduct a cost-effectiveness analysis to inform health-service decisions regarding implementation of such a program.

METHODS

A decision-analytic model was used to compare usual care with the proposed first-trimester screening intervention within the obstetric population (n = 6822) attending two public hospitals within a metropolitan district health service in New South Wales, Australia, between January 2015 and December 2016. The model, applied from early pregnancy, included exposure to a variety of healthcare professionals and addressed type of risk assessment (usual care or first-trimester screening) and use of (compliance with) low-dose aspirin prescribed prophylactically for prevention of PE. All pathways culminated in six possible health outcomes, ranging from no PE to maternal death. Results were presented as the number of cases of PE gained/avoided and the incremental increase/decrease in economic costs arising from the intervention compared with usual care. Significant assumptions were tested in sensitivity/uncertainty analyses.

RESULTS

The intervention produced, across all gestational ages, 31 fewer cases of PE and reduced aggregate economic health-service costs by 1 431 186 Australian dollars over the 2-year period. None of the tested iterations of uncertainty analyses reported additional cases of PE or higher economic costs. The new intervention based on first-trimester screening dominated usual care.

CONCLUSION

This cost-effectiveness analysis demonstrated a reduction in prevalence of preterm PE and substantial cost savings associated with a population-based program of first-trimester prediction and prevention of PE, and supports implementation of such a policy. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Prevalence of hypertensive disorders during pregnancy in France (2010-2018): The Nationwide CONCEPTION Study

Hypertensive disorders of pregnancy (HDP) are one of the leading causes of maternal and fetal morbidity and mortality. We aimed to estimate the prevalence of each HDP in France and to study their associations. All pregnant women who delivered in France between 2010 and 2018 were included in a cohort and followed during their pregnancy and 6 weeks of postpartum. Each HDP occurring during the follow-up was identified. Prevalence of each HDP and cumulative incidence by gestational age were estimated. Incidence rate ratio (IRR) and 95% confidence interval (CI) for preeclampsia among women with preexisting or gestational hypertension (GH) were estimated using Poisson regression and adjusted for age were estimated. Between 2010 and 2018, 6 302 810 deliveries were included. HDP complicated 7.4% of pregnancies. Preeclampsia and GH complicated 2.0% and 4.2% of pregnancies, respectively. Most of preeclampsia cases occurred without a prior HDP. HELLP syndrome represented 10.4% of preeclampsia cases. Compared to nulliparous pregnancies without HDP prior preeclampsia, the age-adjusted IRR of preeclampsia was 6.2 [95% CI: 6.1-6.4] in nulliparous pregnancies with preexisting hypertension and 2.9 [95% CI: 2.8-3.0] in nulliparous pregnancies with GH. In France, HDP occurred in 7.4% of all pregnancies. Women with preexisting chronic hypertension are at high risk to present preeclampsia during pregnancy. Preeclampsia complicated 2.0% of pregnancies in France. Tailoring management of women according to the HDP is a major challenge to avoid complications related to these disorders.

Effect of current guidelines on prevention of pre-eclampsia with low-dose aspirin in primary settings: A population-based case-control study

OBJECTIVE

To evaluate the effect of low-dose aspirin, which was administered at or before the 16th week of pregnancy due to maternal characteristics and history of a pre-existing medical condition, on prevention of pre-eclampsia, and on the birth of a small-for-gestational-age (SGA) neonate without pre-eclampsia in nulliparas in primary settings.

METHODS

We performed a case-control study using population-based data on 47 271 nulliparas with a singleton pregnancy who delivered in Slovenia from 2013 to 2017. The treated group received low-dose aspirin. For the untreated group, propensity score matching was used to perform a 1:1 matching. In the matched sample, we calculated the odds ratios (OR) with a 95% confidence interval (95% CI) with a two-way test for pre-eclampsia, as well as SGA neonates.

RESULTS

In the treated group (n=584), the odds for an SGA neonate were significantly increased by 42.7% (OR 1.427, 95% CI 1.001-2.034). However, we found no significant effect on the odds for pre-eclampsia (OR 1.308, 95% CI 0.847-2.022).

CONCLUSIONS

In anticipation of more substantial population-based data studies, in the Slovenian population, preventive treatment with low-dose aspirin due to maternal characteristics and history of a pre-existing medical condition is not beneficial for the prevention of pre-eclampsia and can harm fetal growth.

Impact of low-dose aspirin on adverse perinatal outcome: meta-analysis and meta-regression

OBJECTIVE

To perform a meta-analysis and meta-regression of randomized controlled trials (RCTs) to evaluate the impact of low-dose aspirin (LDA) on perinatal outcome, independent of its effect on pre-eclampsia (PE), preterm birth and low birth weight.

METHODS

An electronic search of EMBASE, PubMed, CENTRAL, PROSPERO and Google Scholar databases was performed to identify RCTs assessing the impact of LDA in pregnancy, published in English prior to May 2019, which reported perinatal outcomes of interest (placental abruption, delivery mode, low 5-min Apgar score, neonatal acidosis, neonatal intensive care unit admission, periventricular hemorrhage and perinatal death). Risk ratios (RR) and 95% CI were calculated and pooled for analysis. Analysis was stratified according to gestational age at commencement of treatment (≤ 16 weeks vs > 16 weeks) and subgroup analysis was performed to assess the impact of aspirin dose (< 100 mg vs ≥ 100 mg). Meta-regression was used to assess the impact of LDA on perinatal outcome, independent of the reduction in PE, preterm birth and low birth weight.

RESULTS

Forty studies involving 34 807 participants were included. When LDA was commenced ≤ 16 weeks' gestation, it was associated with a significant reduction in the risk of perinatal death (RR, 0.47; 95% CI, 0.25-0.88; P = 0.02; number needed to treat, 92); however, this risk reduction was only seen when a daily dose of ≥ 100 mg was administered. If commenced > 16 weeks' gestation, LDA was associated with a significant reduction in 5-min Apgar score < 7 (RR, 0.75; 95% CI, 0.58-0.96; P = 0.02) and periventricular hemorrhage (RR, 0.68; 95% CI, 0.47-0.99; P = 0.04), but a trend towards an increase in the risk of placental abruption (RR, 1.20; 95% CI, 1.00-1.46; P = 0.06) was also noted. LDA was not associated with any significant increase in adverse events if commenced ≤ 16 weeks gestation. LDA had no effect on delivery mode, irrespective of the gestational age at which it was started. Meta-regression confirmed that the effect of LDA on perinatal death, when treatment was started ≤ 16 weeks' gestation, was independent of any reduction in the rate of PE and preterm birth.

CONCLUSION

LDA improves some important perinatal outcomes, without increasing adverse events such as placental abruption or periventricular hemorrhage, and its utility, if commenced prior to 16 weeks' gestation, may be considered in a wider context beyond the prevention of PE or fetal growth restriction. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

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.

Evidence-Based Prevention of Preeclampsia: Commonly Asked Questions in Clinical Practice

In this review, we discuss the recent literature regarding the prevention of preeclampsia and aim to answer common questions that arise in the routine antenatal care of pregnant women. Prescription of low-dose aspirin for high-risk patients has been shown to reduce the risk of preeclampsia (PE). A daily dose between 100 and 150 mg taken in the evening should be initiated prior to 16 weeks of gestation and can be continued until delivery. Calcium supplementation seems to be advantageous but currently it is only considered for patients with poor dietary intake and high risk for PE. Recent data about heparin are still conflicting, and therefore, heparin can currently not be recommended in the prevention of PE.

Prenatal screening for pre-eclampsia: Frequently asked questions

The current approach to screening for pre-eclampsia is based on guidelines that rely on medical and obstetric history in early pregnancy to select a high-risk group that might benefit from low-dose aspirin. However, combined screening tests with the addition of biophysical and biochemical measurements have shown significantly better detection rates for preterm pre-eclampsia. Furthermore, the administration of aspirin for the 10% screen-positive group can lead to a significant reduction in severe and preterm forms of pre-eclampsia. This review aims to answer frequently asked questions related to the clinical implementation of screening and the management of screening results.

Maternal Outcomes Associated With Lower Range Stage 1 Hypertension

OBJECTIVE

To evaluate maternal and neonatal outcomes in healthy, nulliparous women classified with stage 1 hypertension under the revised American College of Cardiology and American Heart Association Guidelines and to evaluate the effects of low-dose aspirin on maternal and neonatal outcomes in this population.

METHODS

We conducted a secondary analysis of data from a multicenter randomized, double-blind, placebo-controlled trial of low-dose aspirin for prevention of preeclampsia in nulliparous, low-risk women recruited between 13 and 25 weeks of gestation. Of the 3,134 nulliparous women enrolled in the original study, 2,947 women with singleton pregnancies and without missing data were included in this analysis. Blood pressure was measured at enrollment between 13 and 25 weeks of gestation and outcomes were adjudicated from the medical record.

RESULTS

One hundred sixty-four participants were identified with lower range stage 1 hypertension (5.6%), systolic blood pressure 130-135 mm Hg, diastolic blood pressure 80-85 mm Hg, or both by the new American College of Cardiology-American Heart Association guidelines. Within the placebo group (n=1,482), women with stage 1 hypertension had a significantly increased incidence of preeclampsia compared with normotensive women, 15.3% (15/98) vs 5.4% (75/1,384) (relative risk 2.66, 95% CI 1.56-4.54, P<.001). Moreover, women with stage 1 hypertension had an increased incidence of gestational diabetes mellitus (6.1% vs 2.5%, P=.03) and more indicated preterm deliveries (4.2% vs 1.1%, P=.01). Comparing women with stage 1 hypertension and normotensive women receiving low-dose aspirin during pregnancy (n=1,465), no differences in rates of preeclampsia (7.6% vs 4.4%, respectively, P=.2), gestational diabetes mellitus, or indicated preterm deliveries were observed. Rates of placenta abruption, small for gestational age, and spontaneous preterm birth did not differ significantly between groups.

CONCLUSION

Application of the new American College of Cardiology-American Heart Association guidelines in a pregnant population identifies a cohort of women who are at increased risk for preeclampsia, gestational diabetes mellitus, and preterm birth.

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.

A description of the methods of the Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be (nuMoM2b)

OBJECTIVE

The primary aim of the "Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be" is to determine maternal characteristics, which include genetic, physiologic response to pregnancy, and environmental factors that predict adverse pregnancy outcomes.

STUDY DESIGN

Nulliparous women in the first trimester of pregnancy were recruited into an observational cohort study. Participants were seen at 3 study visits during pregnancy and again at delivery. We collected data from in-clinic interviews, take-home surveys, clinical measurements, ultrasound studies, and chart abstractions. Maternal biospecimens (serum, plasma, urine, cervicovaginal fluid) at antepartum study visits and delivery specimens (placenta, umbilical cord, cord blood) were collected, processed, and stored. The primary outcome of the study was defined as pregnancy ending at <37+0 weeks' gestation. Key study hypotheses involve adverse pregnancy outcomes of spontaneous preterm birth, preeclampsia, and fetal growth restriction.

RESULTS

We recruited 10,037 women to the study. Basic characteristics of the cohort at screening are reported.

CONCLUSION

The "Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be" cohort study methods and procedures can help investigators when they plan future projects.

Comparative effect sizes in randomised trials from less developed and more developed countries: meta-epidemiological assessment

OBJECTIVE

To compare treatment effects from randomised trials conducted in more developed versus less developed countries.

DESIGN

Meta-epidemiological study.

DATA SOURCES

Cochrane Database of Systematic Reviews (August 2012).

DATA EXTRACTION

Meta-analyses with mortality outcomes including data from at least one randomised trial conducted in a less developed country and one in a more developed country. Relative risk estimates of more versus less developed countries were compared by calculating the relative relative risks for each topic and the summary relative relative risks across all topics. Similar analyses were performed for the primary binary outcome of each topic.

RESULTS

139 meta-analyses with mortality outcomes were eligible. No nominally significant differences between more developed and less developed countries were found for 128 (92%) meta-analyses. However, differences were beyond chance in 11 (8%) cases, always showing more favourable treatment effects in trials from less developed countries. The summary relative relative risk was 1.12 (95% confidence interval 1.06 to 1.18; P<0.001; I(2)=0%), suggesting significantly more favourable mortality effects in trials from less developed countries. Results were similar for meta-analyses with nominally significant treatment effects for mortality (1.15), meta-analyses with recent trials (1.14), and when excluding trials from less developed countries that subsequently became more developed (1.12). For the primary binary outcomes (127 meta-analyses), 20 topics had differences in treatment effects beyond chance (more favourable in less developed countries in 15/20 cases).

CONCLUSIONS

Trials from less developed countries in a few cases show significantly more favourable treatment effects than trials in more developed countries and, on average, treatment effects are more favourable in less developed countries. These discrepancies may reflect biases in reporting or study design as well as genuine differences in baseline risk or treatment implementation and should be considers when generalising evidence across different settings.

Headache in pregnancy: a nuisance or a new sense?

Headache is a very commonly encountered symptom in pregnancy and is usually due to primary headache disorders which are benign in nature. It can however be quite debilitating for some women who may need therapeutic treatment of which there are several options safe to use in pregnancy. It is equally important though to recognise that headache may be a sign of serious underlying pathology. This paper aims to provide a clinically useful guidance for differentiation between primary and secondary headaches in pregnancy. The primary headache disorders and their management in pregnancy are explored in depth with brief overviews of the causes for secondary headaches and their further investigation and management.

Impact of interventions to prevent and manage preeclampsia and eclampsia on stillbirths

Background

Pre-eclampsia and Eclampsia are relatively common complications of pregnancy, leading to considerable maternal and fetal mortality and morbidity. We sought to review the effect of aspirin, calcium supplementation, antihypertensive agents and magnesium sulphate on risk stillbirths.

Methods

A systematic literature search was conducted to identify studies evaluating the above interventions. We used a standardized abstraction and grading format and performed meta-analyses where data were available from more than one studies. The estimated effect on stillbirths was determined by applying the standard Child Health Epidemiology Reference Group (CHERG) rules for multiple outcomes. For interventions with insufficient evidence for overall effect, a Delphi process was undertaken to estimate effectiveness.

Results

We identified 82 relevant studies. For aspirin, maganesium sulphate and use of antihypertensive we found an insignificant decrease in stillbirth and perinatal mortality. For calcium supplementation, there was a borderline significant reduction in stillbirths (RR 0.81, 95 % CI 0.63-1.03). We undertook a Delphi consultation among experts to assess the potential impact of a package of interventions for the management of pre-eclampsia and eclampsia (antihypertensive, magnesium sulphate and C-section if needed). The Delphi process suggested 20% reduction each in both antepartum and intrapartum stillbirths with the use of this package.

Conclusions

Despite promising benefits of calcium supplementation and aspirin use cases on maternal morbidity and eclampsia in high risk cases, further work is needed to ascertain their benefits in relation to stillbirths. The Delphi process undertaken for assessing potential impact of a package of interventions indicated that this could be associated with 20% reduction in stillbirths, for input into LiST.

Study protocol: Cost effectiveness of two strategies to implement the NVOG guidelines on hypertension in pregnancy: An innovative strategy including a computerised decision support system compared to a common strategy of professional audit and feedback, a randomized controlled trial

Background

Hypertensive disease in pregnancy remains the leading cause of maternal mortality in the Netherlands. Seventeen percent of the clinical pregnancies are complicated by hypertension and 2% by preeclampsia. The Dutch Society of Obstetrics and Gynaecology (NVOG) has developed evidence-based guidelines on the management of hypertension in pregnancy and chronic hypertension. Previous studies showed a low adherence rate to other NVOG guidelines and a large variation in usual care in the different hospitals. An explanation is that the NVOG has no general strategy of practical implementation and evaluation of its guidelines. The development of an effective and cost effective implementation strategy to improve adherence to the guidelines on hypertension in pregnancy is needed.

Methods/Design

The objective of this study is to assess the cost effectiveness of an innovative implementation strategy of the NVOG guidelines on hypertension including a computerised decision support system (BOS) compared to a common strategy of professional audit and feedback. A cluster randomised controlled trial with an economic evaluation alongside will be performed. Both pregnant women who develop severe hypertension or pre-eclampsia and professionals involved in the care for these women will participate. The main outcome measures are a combined rate of major maternal complications and process indicators extracted from the guidelines. A total of 472 patients will be included in both groups. For analysis, descriptive as well as regression techniques will be used. A cost effectiveness and cost utility analysis will be performed according to the intention-to-treat principle and from a societal perspective. Cost effectiveness ratios will be calculated using bootstrapping techniques.