Barbados Low Dose Aspirin Study in Pregnancy (BLASP): a randomised trial for the prevention of pre-eclampsia and its complications

Use and impact of cardiac medication during pregnancy

ABSTRACT 

Cardiovascular disease is the most encountered cause of maternal death during pregnancy in the western world and an increase in maternal mortality due to cardiac causes has been observed. More women with congenital or acquired heart disease have the desire to become pregnant. Pregnancy is known to impose a major hemodynamic burden and also has impacts on the coagulation system. The risk of developing complications is clearly increased as compared with the normal population. For optimal management, it is crucial to have information on the effects of cardiac medications on the fetus. The focus of this article is to discuss the management of cardiac disease in pregnancy, as well as the known safety of cardiac medications for the mother and/or fetus.

Infants at risk of cerebral palsy: a systematic review of outcomes used in Cochrane studies of pregnancy, childbirth and neonatology

OBJECTIVE

To systematically review meta-analyses (MAs) and randomised controlled trials (RCTs) of interventions for infants at risk of cerebral palsy (CP), to determine if consensus exists in study end-points.

METHODS

MAs within the "Neonatal" and "Pregnancy and Childbirth" Review Groups in Cochrane Database of Systematic Reviews (to June 2011) were included if they contained risk factors for CP as a study end-point, and were either published in 2010 or 2011 or cited >20 times in Sciverse Scopus. Up to 20 RCTs from each MA were included. Outcome measures, definitions and cut-points for ordinal groupings were extracted from MAs and RCTs and frequencies calculated.

RESULTS

Twenty-two MAs and 165 RCTs were appraised. High consistency existed in types of outcome domains listed as important in MAs. For 10/16 most frequently cited outcome domains, <50% of RCTs contributed data for meta-analyses. Low consistency in outcome definitions, measures, cut-points in RCTs and long-term follow-up prohibited data aggregation.

CONCLUSIONS

Variation in outcome measurement and long-term follow up has hampered the ability of RCTs to contribute data on important outcomes for CP, resulting in lost opportunities to measure the impact of maternal and neonatal interventions. There is an urgent need for and long-term follow up of these interventions and an agreed set of standardised and clinically relevant common data elements for study end-points.

Prediction and prevention of ischemic placental disease

Preeclampsia, intrauterine growth restriction (IUGR), and placental abruption are obstetrical conditions that constitute the syndrome of ischemic placental disease or IPD, the leading cause of indicated preterm birth and an important cause of neonatal morbidity and mortality. While the phenotypic manifestations vary significantly for preeclampsia, IUGR, and abruption, these conditions may share a common underlying etiology as evidenced by: (1) shared clinical risk factors, (2) increased recurrence risk across pregnancies as well as increased co-occurrence of IPD conditions within a pregnancy, and (3) findings that suggest the underlying pathophysiologic processes may be similar. IPD is of major clinical importance and accounts for a large proportion of indicated preterm delivery ranging from the periviable to late preterm period. Successful prevention of IPD and resultant preterm delivery could substantially improve neonatal and maternal outcomes. This article will review the following topics: (1) The complicated research literature on aspirin and the prevention of preeclampsia and IUGR. (2) Research evidence on other medical interventions to prevent IPD. (3) New clinical interventions currently under investigations, including statins. (4) Current clinical recommendations for prevention of ischemic placental disease.

Diagnosis, evaluation, and management of the hypertensive disorders of pregnancy

OBJECTIVE

This guideline summarizes the quality of the evidence to date and provides a reasonable approach to the diagnosis, evaluation and treatment of the hypertensive disorders of pregnancy (HDP).

EVIDENCE

The literature reviewed included the previous Society of Obstetricians and Gynaecologists of Canada (SOGC) HDP guidelines from 2008 and their reference lists, and an update from 2006. Medline, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Registry of Controlled Trials (CCRCT) and Database of Abstracts and Reviews of Effects (DARE) were searched for literature published between January 2006 and March 2012. Articles were restricted to those published in French or English. Recommendations were evaluated using the criteria of the Canadian Task Force on Preventive Health Care and GRADE.

Prevention of perinatal death and adverse perinatal outcome using low-dose aspirin: a meta-analysis

OBJECTIVE

To compare early vs late administration of low-dose aspirin on the risk of perinatal death and adverse perinatal outcome.

METHODS

Databases were searched for keywords related to aspirin and pregnancy. Only randomized controlled trials that evaluated the prophylactic use of low-dose aspirin (50-150 mg/day) during pregnancy were included. The primary outcome combined fetal and neonatal death. Pooled relative risks (RR) with their 95% CIs were compared according to gestational age at initiation of low-dose aspirin (≤ 16 vs > 16 weeks of gestation).

RESULTS

Out of 8377 citations, 42 studies (27 222 women) were included. Inclusion criteria were risk factors for pre-eclampsia, including: nulliparity, multiple pregnancy, chronic hypertension, cardiovascular or endocrine disease, prior gestational hypertension or fetal growth restriction, and/or abnormal uterine artery Doppler. When compared with controls, low-dose aspirin started at ≤ 16 weeks' gestation compared with low-dose aspirin started at >16 weeks' gestation was associated with a greater reduction of perinatal death (RR = 0.41 (95% CI, 0.19-0.92) vs 0.93 (95% CI, 0.73-1.19), P = 0.02), pre-eclampsia (RR = 0.47 (95% CI, 0.36-0.62) vs 0.78 (95% CI, 0.61-0.99), P < 0.01), severe pre-eclampsia (RR = 0.18 (95% CI, 0.08-0.41) vs 0.65 (95% CI, 0.40-1.07), P < 0.01), fetal growth restriction (RR = 0.46 (95% CI, 0.33-0.64) vs 0.98 (95% CI, 0.88-1.08), P < 0.001) and preterm birth (RR = 0.35 (95% CI, 0.22-0.57) vs 0.90 (95% CI, 0.83-0.97), P < 0.001).

CONCLUSION

Low-dose aspirin initiated at ≤ 16 weeks of gestation is associated with a greater reduction of perinatal death and other adverse perinatal outcomes than when initiated at >16 weeks.

ASPIRIN ADMINISTRATION FOR PREVENTION OF ADVERSE PREGNANCY OUTCOMES

The prophylactic use of low-dose aspirin for prevention of preeclampsia has been an important research question in obstetrics for the last three decades. In 1979, Crandon and Isherwood observed that nulliparous women who had taken aspirin regularly during pregnancy were less likely to have preeclampsia than women who did not. In 1985, Beaufils et al published the first randomized trial suggesting that 150 mg aspirin and 300 mg dipyridamole daily from 3 months’ gestation onwards decreased the risk of preeclampsia, fetal growth restriction and stillbirth in high-risk women. Subsequently, more than 50 trials have been carried out throughout the world and a meta-analysis of these studies reported that the administration of low-dose aspirin in high-risk pregnancies is associated with a decrease in the rate of preeclampsia by approximately 10%. Consequently, several national professional bodies recommend that high-risk pregnancies should be treated with aspirin (50–150 mg daily).

Antiplatelet drugs: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

The article describes the mechanisms of action, pharmacokinetics, and pharmacodynamics of aspirin, dipyridamole, cilostazol, the thienopyridines, and the glycoprotein IIb/IIIa antagonists. The relationships among dose, efficacy, and safety are discussed along with a mechanistic overview of results of randomized clinical trials. The article does not provide specific management recommendations but highlights important practical aspects of antiplatelet therapy, including optimal dosing, the variable balance between benefits and risks when antiplatelet therapies are used alone or in combination with other antiplatelet drugs in different clinical settings, and the implications of persistently high platelet reactivity despite such treatment.

A meta-analysis of low-dose aspirin for prevention of preeclampsia

BACKGROUND

Low-dose aspirin (LDA) is widely used for prevention of preeclampsia. However, conflicting results have been obtained from various studies.

AIM

The aim of our study was to evaluate the effect of LDA in prevention of preeclampsia in high-risk and low-risk women.

MATERIALS AND METHODS

A total of 19 randomized control trials were identified using PUBMED search engine and Cochrane Clinical Trial register. The study population was divided into high-risk and low-risk groups. The effect measured was incidence of preeclampsia in women taking either LDA or placebo where the relative risk (RR) and the 95% confidence interval (CI) were calculated for both groups.

RESULTS

A total of 28237 women were studied, out of which 16550 were in the low-risk group while 11687 were in the high-risk group. The overall incidence of preeclampsia was 7.4%. With the aspirin group it was 6.9% while in the placebo group it was 7.8%. In the high-risk group there was 21% reduction in the risk of preeclampsia associated with the use of aspirin (RR 0.79, 95% CI 0.65-0.97). However, LDA is not effective in reducing the risk in low-risk population (RR 0.86, 95% CI 0.64-1.17).

CONCLUSION

LDA has a small effect in the prevention of preeclampsia in women considered to be at high risk for the disease. However, it is not effective in reducing the risk in the low-risk group.

Prevention of pre-eclampsia with low-dose aspirin or vitamins C and E in women at high or low risk: a systematic review with meta-analysis

The aim of this study is to review literature about the efficacy of low dose aspirin (LDA) and vitamins C/E (VCE) to prevent pre-eclampsia in women at high and low risk. Randomized clinical trials were included and stratified for high and low risk women. Inclusion criteria were: assignment of patients in treated or placebo groups, definition of pre-eclampsia according to the guidelines of the International Society for the Study of Hypertension in Pregnancy. Exclusion criteria were: omitting at least one of the inclusion criteria, trials involving women with pre-eclampsia at trial entry, studies investigating hypertensive disorders other than pre-eclampsia, prophylaxis of intrauterine growth restriction with low-dose aspirin or vitamins C/E, non-randomized studies and data reported in graphs or percentages. The incidence of pre-eclampsia, perinatal outcomes and adverse effects attributable to LDA and VCE were compared between treated women and placebo. Inter-studies heterogeneity was tested. P<0.05 was considered significant. pooled odds ratios (OR) with 95% confidence intervals (95% CI) were calculated. PRISMA guidelines were followed. Fifteen studies were pooled. LDA did not decrease the incidence of pre-eclampsia in high-risk (396/5025 - 8% vs placebo: 464/5027 - 9%; P=0.05; OR: 0.72; 95% CI: 0.51-1.00) and low-risk (137/4939 - 3% vs placebo: 166/4962 - 3%; P=0.10; OR: 0.82; 95% CI: 0.65-1.04) women. Similarly, VCE did not reduce the incidence of pre-eclampsia in high-risk (VCE: 250/1744 - 14% vs placebo: 275/1741 - 16%; P=0.24; OR: 0.84; 95% CI: 0.63-1.12) and low-risk (VCE: 56/935 - 6% vs placebo 47/942 - 5%; P=0.57; OR: 1.20; 95% CI: 0.82-1.75) women. In high-risk women, other hypertensive disorders were more frequent in VCE (121/1692 - 7%) than placebo (79/1693 - 5%; P=0.002). Perinatal outcomes were not improved by LDA or VCE.

CONCLUSION

there is no evidence to support the administration of LDA or VCE to prevent pre-eclampsia.

Maternal plasma concentrations of angiogenic/anti-angiogenic factors are of prognostic value in patients presenting to the obstetrical triage area with the suspicion of preeclampsia

OBJECTIVE

To determine whether maternal plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and -2 could identify patients at risk for developing preeclampsia (PE) requiring preterm delivery.

STUDY DESIGN

Patients presenting with the diagnosis "rule out PE" to the obstetrical triage area of our hospital at <37 weeks of gestation (n = 87) were included in this study. Delivery outcomes were used to classify patients into four groups: I) patients without PE or those with gestational hypertension (GHTN) or chronic hypertension (CHTN) who subsequently developed PE at term (n = 19); II): mild PE who delivered at term (n = 15); III): mild disease (mild PE, GHTN, CHTN) who subsequently developed severe PE requiring preterm delivery (n = 26); and IV): diagnosis of severe PE (n = 27). Plasma concentrations of PlGF, sEng, sVEGFR-1 and -2 were determined at the time of presentation by ELISA. Reference ranges for analytes were constructed by quantile regression in our laboratory (n = 180; 1046 samples). Comparisons among groups were performed using multiples of the median (MoM) and parametric statistics after log transformation. Receiver operating characteristic curves, logistic regression and survival analysis were employed for analysis.

RESULTS

The mean MoM plasma concentration of PlGF/sVEGFR-1, PlGF/sEng, PlGF, sVEGFR-1 and -2, and sEng in Group III was significantly different from Group II (all p < 0.05). A plasma concentration of PlGF/sVEGFR-1 ≤ 0.05 MoM or PlGF/sEng ≤0.07 MoM had the highest likelihood ratio of a positive test (8.3, 95% CI 2.8-25 and 8.6, 95% CI 2.9-25, respectively), while that of PlGF ≤0.396 MoM had the lowest likelihood ratio of a negative test (0.08, 95% CI 0.03-0.25). The association between low plasma concentrations of PlGF/sVEGFR-1 (≤0.05 MoM) as well as that of PlGF/sEng (≤0.07 MoM) and the development of severe PE remained significant after adjusting for gestational age at presentation, average systolic and diastolic blood pressure, and a history of chronic hypertension [adjusted odds ratio (OR) = 27 (95% CI 6.4-109) and adjusted OR 30 (95% CI 6.9-126), respectively]. Among patients who presented <34 weeks gestation (n = 59), a plasma concentration of PlGF/sVEGFR-1 < 0.033 MoM identified patients who delivered within 2 weeks because of PE with a sensitivity of 93% (25/27) and a specificity of 78% (25/32). This cut-off was associated with a shorter interval-to-delivery due to PE [hazard ratio = 6 (95% CI 2.5-14.6)].

CONCLUSIONS

Plasma concentrations of angiogenic/anti-angiogenic factors are of prognostic value in the obstetrical triage area. These observations support the value of these biomarkers in the clinical setting for the identification of the patient at risk for disease progression requiring preterm delivery.

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.

Colour Doppler ultrasound of spiral artery blood flow in the prediction of pre-eclampsia and intrauterine growth restriction

Pre-eclampsia and intrauterine growth restriction are responsible for significant maternal and fetal morbidity and mortality worldwide. Identifying pregnancies at highest risk for their development would allow increased surveillance in individual pregnancies and also allow therapeutic trials to decrease their incidences in the future. To date, multiple attempts to develop a screening test for these disorders have met with limited success. Proposed screening methods have included maternal serum biochemical parameters as well as ultrasonographic markers. Uterine artery Doppler, direct evaluation of the spiral arteries using colour and spectral Doppler, three-dimensional placental volume analysis and, most recently, three-dimensional power Doppler angiography have all been suggested. Although an adequate screening method remains elusive, advances in ultrasound technology have improved our ability to observe the pathophysiologic changes that occur with these conditions early in pregnancy, bringing us closer to a reproducible screening model.

Physiologic and pathologic changes of platelets in pregnancy

Platelets are key players in haemostasis and thrombus formation. Defects affecting platelets during pregnancy can lead to heterogeneous complications, such as thrombosis, first trimester miscarriage and postpartum haemorrhage. The incidence of complications is increased in women who have heritable platelet function disorders. Modifications of platelet count or platelet functions during normal pregnancy and preeclampsia will be summarized and the management of pregnant women with heritable platelet function disorders will be discussed.

Critical Overview on the Benefits and Harms of Aspirin

Aspirin is widely used internationally for a variety of indications, with the most prominent one being that of cardiovascular disease. However, aspirin has also been proposed as a treatment option in a diverse range of conditions such as diabetes mellitus, cancer prevention, and obstetrics. In our overview, we critically appraise the current evidence from recent systematic reviews and meta-analyses covering the benefits of aspirin across these conditions. We also look at evidence that some patients may not derive benefit due to the concept of aspirin resistance. Aspirin is also associated with the potential for significant harm, principally from haemorrhagic adverse events. We critically appraise the threat of haemorrhagic complications, and weigh up these risks against that of any potential benefit.

Metaanalysis vs large clinical trials: which should guide our management?

Large, randomized clinical trials have long been considered the gold standard to guide clinical care. Metaanalysis is a type of analysis in which results of a number of randomized clinical trials are combined and a summary measure of effect for a given treatment is ascertained. The clinician in practice often is faced with a dilemma regarding the type of evidence that should be used to guide clinical practice; for many clinical problems, there are both randomized controlled trials and metaanalyses available. The cases of calcium and aspirin therapy for the prevention of preeclampsia afford an opportunity to explore the benefits and limitations of each type of study to guide clinical practice. We conclude that, when available, large randomized clinical trials should be used to guide clinical practice.

Low-dose aspirin reduces uteroplacental vascular impedance in early and mid gestation in IVF and ICSI patients: a randomized, placebo-controlled double-blind study

OBJECTIVE

To determine whether low-dose aspirin improves uteroplacental hemodynamics in unselected in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) subjects when medication is started concomitantly with controlled ovarian hyperstimulation.

METHODS

Thirty-seven pregnant women who had undergone IVF/ICSI and had been randomized to receive 100 mg aspirin (n = 17) or placebo (n = 20) daily, started concomitantly with controlled ovarian hyperstimulation, were included in this study. Doppler ultrasound examination was performed at 6, 10, 13 and 18 weeks' gestation. Uterine artery (UtA) pulsatility index (PI) was calculated and bilateral UtA notching was noted. Subplacental arcuate artery PI was obtained at 6 and 10 weeks' gestation. Umbilical artery (UA) PI and mean velocity were calculated at 10, 13 and 18 weeks' gestation. In the aspirin group there was one early pregnancy miscarriage, and one patient discontinued the study medication owing to early pregnancy bleeding. A total of 15 women in the aspirin group and 20 women in the placebo group underwent the complete ultrasound protocol.

RESULTS

At 6 weeks' gestation, arcuate artery PI and at 18 weeks' gestation, UtA PI were lower (P < 0.05) in the aspirin group than in the placebo group. At 18 weeks' gestation, bilateral UtA notching tended to be more common in the placebo group (40%) than in the aspirin group (13%) (P = 0.06). UA PI and mean velocity did not differ significantly between the groups.

CONCLUSION

Low-dose aspirin reduces uteroplacental vascular impedance in early and mid pregnancy in unselected IVF/ICSI subjects when medication is started concomitantly with controlled ovarian hyperstimulation.

Antiplatelet drugs: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This article about currently available antiplatelet drugs is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). It describes the mechanism of action, pharmacokinetics, and pharmacodynamics of aspirin, reversible cyclooxygenase inhibitors, thienopyridines, and integrin alphaIIbbeta3 receptor antagonists. The relationships among dose, efficacy, and safety are thoroughly discussed, with a mechanistic overview of randomized clinical trials. The article does not provide specific management recommendations; however, it does highlight important practical aspects related to antiplatelet therapy, including the optimal dose of aspirin, the variable balance of benefits and hazards in different clinical settings, and the issue of interindividual variability in response to antiplatelet drugs.

WITHDRAWN: Antiplatelet agents for preventing and treating pre-eclampsia

BACKGROUND

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

OBJECTIVES

To assess the effectiveness and safety of antiplatelet agents when given to women at risk of developing pre-eclampsia, and to those with established pre-eclampsia.

SEARCH STRATEGY

This review drew on the search strategy developed for the Pregnancy and Childbirth Group as a whole. The Cochrane Controlled Trials Register was also searched, The Cochrane Library 1999 Issue 1, Embase was searched from 1994-1999 and hand searches were performed of the congress proceedings of the International and European Societies for the Study of Hypertension in Pregnancy.

SELECTION CRITERIA

All randomised trials comparing antiplatelet agents with either placebo or no antiplatelet agent during pregnancy. Quasi random study designs were excluded. Participants were pregnant women considered to be at risk of developing pre-eclampsia, and those with pre-eclampsia before delivery. Women treated postpartum were excluded. Interventions were any comparisons of an antiplatelet agent (such as low dose aspirin or dipyridamole) with either placebo or no antiplatelet agent.

DATA COLLECTION AND ANALYSIS

Assessment of trials for inclusion in the review and extraction of data was performed independently and unblinded by two reviewers. Data were entered into the Review Manager software and double checked.

MAIN RESULTS

Forty two trials involving over 32,000 women were included in this review, with 30,563 women in the prevention trials. There is a 15% reduction in the risk of pre-eclampsia associated with the use of antiplatelet agents [32 trials with 29,331 women; relative risk (RR) 0.85, 95% confidence interval (0.78, 0.92); Number needed to treat (NNT) 89, (59, 167)]. This reduction is regardless of risk status at trial entry or whether a placebo was used, and irrespective of the dose of aspirin or gestation at randomisation.Twenty three trials (28,268 women) reported preterm delivery. There is a small (8%) reduction in the risk of delivery before 37 completed weeks [RR 0.92, (0.88, 0.97); NNT 72 (44, 200)]. Baby deaths were reported in 30 trials (30,093 women). Overall there is a 14% reduction in baby deaths in the antiplatelet group [RR 0.86, (0.75, 0.98); NNT 250 (125, >10000)]. Small for gestational age babies were reported in 25 trials (20,349 women), with no overall difference between the groups, RR 0.92, (0.84, 1.01). There were no significant differences between treatment and control groups in any other measures of outcome. Five trials compared antiplatelet agents with placebo or no antiplatelet agent for the treatment of pre-eclampsia. There are insufficient data for any firm conclusions about the possible effects of these agents when used for treatment of pre-eclampsia.

AUTHORS' CONCLUSIONS

Antiplatelet agents, in this review largely low dose aspirin, have small-moderate benefits when used for prevention of pre-eclampsia. Further information is required to assess which women are most likely to benefit, when treatment should be started, and at what dose.

Antiplatelet agents for prevention of pre-eclampsia: a meta-analysis of individual patient data

BACKGROUND

Pre-eclampsia is a major cause of mortality and morbidity during pregnancy and childbirth. Antiplatelet agents, especially low-dose aspirin, might prevent or delay pre-eclampsia, and thereby improve outcome. Our aim was to assess the use of antiplatelet agents for the primary prevention of pre-eclampsia, and to explore which women are likely to benefit most.

METHODS

We did a meta-analysis of individual patient data from 32,217 women, and their 32,819 babies, recruited to 31 randomised trials of pre-eclampsia primary prevention.

FINDINGS

For women assigned to receive antiplatelet agents rather than control, the relative risk of developing pre-eclampsia was 0.90 (95% CI 0.84-0.97), of delivering before 34 weeks was 0.90 (0.83-0.98), and of having a pregnancy with a serious adverse outcome was 0.90 (0.85-0.96). Antiplatelet agents had no significant effect on the risk of death of the fetus or baby, having a small for gestational age infant, or bleeding events for either the women or their babies. No particular subgroup of women was substantially more or less likely to benefit from antiplatelet agents than any other.

INTERPRETATION

Antiplatelet agents during pregnancy are associated with moderate but consistent reductions in the relative risk of pre-eclampsia, of birth before 34 weeks' gestation, and of having a pregnancy with a serious adverse outcome.

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 for women at risk of developing pre-eclampsia.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2005, Issue 1), EMBASE (1994 to November 2005) and handsearched congress proceedings of the International and European Societies for the Study of Hypertension in Pregnancy.

SELECTION CRITERIA

All randomised trials comparing antiplatelet agents with either placebo or no antiplatelet agent were included. Quasi-random studies were excluded. Participants were pregnant women at risk of developing pre-eclampsia. Interventions were any comparisons of an antiplatelet agent (such as low-dose aspirin or dipyridamole) with either placebo or no antiplatelet.

DATA COLLECTION AND ANALYSIS

Two authors assessed trials for inclusion and extracted data independently.

MAIN RESULTS

Fifty-nine trials (37,560 women) are included. There is a 17% reduction in the risk of pre-eclampsia associated with the use of antiplatelet agents ((46 trials, 32,891 women, relative risk (RR) 0.83, 95% confidence interval (CI) 0.77 to 0.89), number needed to treat (NNT) 72 (52, 119)). Although there is no statistical difference in RR based on maternal risk, there is a significant increase in the absolute risk reduction of pre-eclampsia for high risk (risk difference (RD) -5.2% (-7.5, -2.9), NNT 19 (13, 34)) compared with moderate risk women (RD -0.84 (-1.37, -0.3), NNT 119 (73, 333)). Antiplatelets were associated with an 8% reduction in the relative risk of preterm birth (29 trials, 31,151 women, RR 0.92, 95% CI 0.88 to 0.97); NNT 72 (52, 119)), a 14% reduction in fetal or neonatal deaths (40 trials, 33,098 women, RR 0.86, 95% CI 0.76 to 0.98); NNT 243 (131, 1,666) and a 10% reduction in small-for-gestational age babies (36 trials, 23,638 women, RR 0.90, 95% CI0.83 to 0.98). There were no statistically significant differences between treatment and control groups for any other outcomes.

AUTHORS' CONCLUSIONS

Antiplatelet agents, largely low-dose aspirin, have moderate benefits when used for prevention of pre-eclampsia and its consequences. Further information is required to assess which women are most likely to benefit, when treatment is best started, and at what dose.

Decline in, and lack of difference between, average birth weights among African and Portuguese babies in Portugal

BACKGROUND

In preliminary data in Portugal, we found that African babies of migrant mothers were heavier than White Portuguese babies born in Lisbon. We investigate whether this pattern is replicated in the national data, and in addition the trends in birth weight in these groups.

METHODS

DESIGN AND SETTING

Births registered between 1995 and 2002 classified by reported nationality of mothers.

PARTICIPANTS

849,595 Portuguese births ('Portuguese' nationality, predominantly of European descent) and 22,463 African births ('Angola', 'Cape Verde', or 'Guinea Bissau, Republic of Guinea or Equatorial Guinea' nationality, predominantly of African origin).

RESULTS

Among Portuguese births, there was a decline in births to teenaged mothers and an increase to mothers aged >or=35 years, with >9 years of education or in a non-manual class, but among African births there was an increase in births to teenaged mothers and a decline to mothers from advantaged socioeconomic backgrounds. Using the Wilcox-Russell method, overall mean birth weights of term Portuguese (3,303, SD 424 g) and African (3297, SD 441 g) babies were not different but the percentage of small preterm births was higher among African (4.7%) than among Portuguese (2.9%) births. Between 1995 and 2002, mean birth weight of term Portuguese babies declined by 58 g (3,334-3,276 g) and of African babies by 57 g (3,341-3,284 g). The left shift of the birth weight distributions was independent of maternal age, parity, and social factors among Portuguese babies, but among African babies the decrease appeared to be associated with socioeconomic advantage.

CONCLUSION

There has been a downward trend in birth weights in Portugal among both Portuguese and African term births, but average birth weights of the two groups were similar.

Prevention of preeclampsia with low-dose aspirin -- a systematic review and meta-analysis of the main randomized controlled trials

The purpose of this paper is to evaluate the effectiveness of low-dose aspirin in the prevention of preeclampsia in low-risk and high-risk women. We identified randomized clinical trials of the use of low-dose aspirin to prevent preeclampsia through the PUBMED search engine, and through the Cochran Library database. Twenty-two studies met our inclusion criteria, and were divided according to the studied population into 2 groups: trials with women at low risk for preeclampsia and trials with women at high risk. Effects were measured through the incidence of preeclampsia in women taking either placebo or aspirin, in studies where the relative risks and the 95% confidence intervals were calculated for both groups. A total of 33,598 women were studied, comprising 5 trials with 16,700 women at low-risk and 17 trials including 16,898 women at high risk. The incidence of preeclampsia was 3.75% (626/17,700), in the low-risk group, 9.01% (1,524/16,898) in the high-risk group, and 6.40% (2,150/33,598) overall. Low-dose aspirin had no statistically significantly effect on the incidence of preeclampsia in the low-risk group (RR = 0.95, 95% CI = 0.81-1.11), but had a small beneficial effect in the high-risk group (RR = 0.87, 95% CI = 0.79-0.96). Therefore, low-dose aspirin is mildly beneficial in terms of reducing the incidence of preeclampsia in women at high risk of developing preeclampsia.

Recurrent preeclampsia and perinatal outcome: a study of women with recurrent preeclampsia compared with women with preeclampsia who remained normotensive during their prior pregnancies

OBJECTIVE

To evaluate the impact of preeclampsia recurrence on perinatal outcome.

MATERIALS AND METHODS

A case-controlled study was performed in multiparous women who developed preeclampsia in index pregnancy (n = 64). Among these, women who had preeclampsia in previous pregnancies (n = 21) were compared to those who remained normotensive during their prior pregnancies (n = 43). Maternal and fetal variables were compared. Multivariate logistic analyses were performed to examine the impact of preeclampsia recurrence on fetal loss, preterm delivery, small for gestational age (SGA) occurrence and respiratory distress syndrome adjusted for confounding variables.

RESULTS

No statistical significant difference was observed between the two groups in terms of age, delivery weeks, steroid use and laboratory markers. Fetal loss was higher in women with recurrent preeclampsia (19.0%) than in women with preeclampsia who had a normotensive pregnancy history (4.7%), with adjusted odds ratio (OR) of 5.77 [95% confidence interval (CI) 0.84-39.54].

CONCLUSION

Women with recurrent preeclampsia had a higher rate of perinatal loss compared to women with preeclampsia who were normotensive in their prior pregnancies.

Platelet-Active Drugs: The Relationships Among Dose, Effectiveness, and Side Effects

This article discusses platelet active drugs as part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. New data on antiplatelet agents include the following: (1) the role of aspirin in primary prevention has been the subject of recommendations based on the assessment of cardiovascular risk; (2) an increasing number of reports suggest a substantial interindividual variability in the response to antiplatelet agents, and various phenomena of "resistance" to the antiplatelet effects of aspirin and clopidogrel; (3) the benefit/risk profile of currently available glycoprotein IIb/IIIa antagonists is substantially uncertain for patients with acute coronary syndromes who are not routinely scheduled for early revascularization; (4) there is an expanding role for the combination of aspirin and clopidogrel in the long-term management of high-risk patients; and (5) the cardiovascular effects of selective and nonselective cyclooxygenase-2 inhibitors have been the subject of increasing attention.

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 platelet-derived vasoconstrictor and stimulant of platelet aggregation. These observations led to the hypotheses that antiplatelet agents, low-dose aspirin in particular, might prevent or delay the development of pre-eclampsia.

OBJECTIVES

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

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (September 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2003), EMBASE (1994 to 2003) and we handsearched the congress proceedings of the International and European Societies for the Study of Hypertension in Pregnancy.

SELECTION CRITERIA

All randomised trials comparing antiplatelet agents with either placebo or no antiplatelet agent during pregnancy. Quasi-random study designs were excluded. Participants were pregnant women considered to be at risk of developing pre-eclampsia. Interventions were any comparisons of an antiplatelet agent (such as low-dose aspirin or dipyridamole) with either placebo or no antiplatelet agent.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trials for inclusion in the review and extracted data. We entered data into the Review Manager software and double checked.

MAIN RESULTS

Fifty-one trials involving 36,500 women are included in this review. There is a 19% reduction in the risk of pre-eclampsia associated with the use of antiplatelet agents ((43 trials, 33,439 women; relative risk (RR) 0.81, 95% confidence interval (CI) 0.75 to 0.88); number needed to treat (NNT) 69 (51, 109)).Twenty-eight trials (31,845 women) reported preterm birth. There is a small (7%) reduction in the risk of delivery before 37 completed weeks ((RR 0.93, 95% CI 0.89 to 0.98); NNT 83 (50, 238)). Fetal or neonatal deaths were reported in 38 trials (34,010 women). Overall there is a 16% reduction in baby deaths in the antiplatelet group (RR 0.84, 95% CI 0.74 to 0.96); NNT 227 (128, 909)). Small-for-gestational age babies were reported in 32 trials (24,310 women), with an 8% reduction in risk (RR 0.92, 95% CI 0.85 to 1.00). There were no significant differences between treatment and control groups in any other measures of outcome.

REVIEWER'S CONCLUSIONS

Antiplatelet agents, in this review largely low-dose aspirin, have small-moderate benefits when used for prevention of pre-eclampsia. Further information is required to assess which women are most likely to benefit, when treatment is best started, and at what dose.

Cerebrovascular Disease in Pregnancy

Stroke during pregnancy is a special category of stroke in young women. Although the absolute risk is small, there are diverse causes, including those inherent to the pregnant state, that may have a significant impact on maternal and fetal outcome. Severe pre-eclampsia and eclampsia are commonly associated with ischemic and hemorrhagic stroke, but must not be presumed the sole cause of stroke in pregnant women. Magnesium sulfate is the treatment of choice to prevent eclampsia. Randomized clinical trials in pregnant women are not available to provide guidance for the treatment of ischemic and hemorrhagic stroke in pregnant women. Various antithrombotic agents may be safely used during specific stages of pregnancy for treatment and prevention of ischemic stroke, with low-dose aspirin, unfractionated heparin, and low molecular weight heparin the preferred agents. Low molecular weight heparin may be safer than unfractionated heparin. Treatment of parenchymatous intracerebral hemorrhage and subarachnoid hemorrhage during pregnancy and the puerperium must be individualized. Aneurysms may be treated with neurosurgical clipping or endovascular coiling, depending on neurosurgical considerations. Cesarean or vaginal delivery may be used depending on the timing of delivery, adequacy of aneurysm occlusion, and risk to mother and fetus. Arteriovenous malformations are best treated in a multimodal fashion at a specialized treatment center.

Administration time-dependent influence of aspirin on blood pressure in pregnant women

This study prospectively investigates the potential influence of low-dose aspirin on blood pressure in pregnant women who were at a higher risk of developing preeclampsia than that of the general obstetric population and who received aspirin at different times of the day according to their rest-activity cycle. A double-blind, randomized, controlled trial was conducted in 341 pregnant women (181 primipara) randomly assigned to 1 of 6 possible groups according to treatment (either placebo or aspirin, 100 mg/day, starting at 12 to 16 weeks of gestation) and the time of treatment: on awakening (time 1), 8 hours after awakening (time 2), or before bedtime (time 3). Blood pressure was automatically monitored for 48 consecutive hours every 4 weeks from the day of recruitment until delivery, as well as at puerperium. There was no effect of aspirin on blood pressure at time 1 (compared with placebo). A blood pressure reduction was highly statistically significant when aspirin was given at time 2 and, to a greater extent, at time 3 (mean reductions of 9.7/6.5 mm Hg in 24-hour mean for systolic/diastolic blood pressure at the time of delivery as compared with placebo given at bedtime). Differences in blood pressure among women receiving aspirin at different circadian times disappeared at puerperium (P>0.096). Results indicate a highly significant effect of aspirin on blood pressure that is markedly dependent on the time of aspirin administration with respect to the rest-activity cycle. Timed use of aspirin at low dose effectively contributes to blood pressure control in women at high risk for preeclampsia.

Preeclampsia. Part 1: clinical and pathophysiologic considerations

Preeclampsia-eclampsia is still one of the leading causes of maternal and fetal morbidity and mortality. Despite active research for many years, the etiology of this disorder exclusive to human pregnancy is an enigma. Recent evidence suggests there may be several underlying causes or predispositions leading to the signs of hypertension, proteinuria, and edema, findings that allow us to make the diagnosis of the "syndrome" of preeclampsia. Despite improved prenatal care, severe preeclampsia and eclampsia still occur. Although understanding of the pathophysiology of these disorders has improved, treatment has not changed significantly in over 50 years. Although postponement of delivery in selected women with severe preeclampsia improves fetal outcome to a degree, this is not done without risk to the mother. In the United States, magnesium sulfate and hydralazine are the most commonly used medications for seizure prophylaxis and hypertension in the intrapartum period. The search for the underlying cause of this disorder and for a clinical marker to predict those women who will develop preeclampsia-eclampsia is ongoing, with its prevention the ultimate goal. This review begins with the clinical and pathophysiologic aspects of preeclampsia-eclampsia (Part 1). In Part 2, the experimental observations, the search for predictive factors, and the genetics of this disorder will be reviewed.

[Criteria of pregnancy termination in women with preeclampsia]

Preeclampsia remains an important cause of maternal and neonatal mortality and morbidity. Delivery is always the appropriate therapy for the mother but may be responsible for neonatal adverse outcomes, particularly when it occurs at less than < 34 weeks' gestation. In women with severe preeclampsia at < 34 weeks expectant management to improve neonatal mortality and morbidity may be performed under close monitoring of both the mother and the fetus. Any severe condition of the mother (HELLP syndrome, abruptio placentae, eclampsia) or the fetus (abnormal fetal heart rate) should lead to prompt delivery. In women with mild preeclampsia, expectant management should be performed until 38 weeks gestation.

Correlations between serum assays of human chorionic gonadotrophin (hCG) and human placental lactogen (hPL) and pre-eclampsia or intrauterine growth restriction (IUGR) among nulliparas younger than 38 years

OBJECTIVE

To study the relation between serum human chorionic gonadotrophin (hCG) levels measured at 15-18 weeks and gestational disorders, assess their correlation with the artery uteroplacental Doppler (AUD) at 24 weeks among nulliparas, and assess the predictivity of the hCG/hPL (human placental lactogen) ratio for pre-eclampsia.

STUDY DESIGN

Retrospective study of two groups of women younger than 38 years old: one with an elevated serum hCG level (2 MoM (multiples of the median) or more) and a normal fetal karyotype (group A), and the other with a lower hCG level (group B). Within each group, we studied the nulliparas separately (respectively groups AO and BO). We analyzed the double screening, elevated hCG levels with abnormal AUD, for the predicting of hypertensive disorders.

RESULTS

Elevated hCG levels were significantly (p<0.05) more prevalent among women who developed gestational diabetes (groups A and AO) and among nulliparas with pregnancy-induced hypertension and pre-eclampsia (AO). Among nulliparas, the combination of the hCG assay and a subsequent Doppler increased the positive predictive value (PPV) of the assay from 19 to 75%, without reducing its negative predictive value (NPV) for gestational vascular disorders. The hCG/hPL ratio did not improve the predictivity of the hCG assay alone for pre-eclampsia.

CONCLUSIONS

An hCG level of 2 MoM or more at 15-18 weeks identifies a group of women at risk of gestational vascular disorders; it therefore ought to lead to an AUD at 24 weeks. This double screening should be able to define a population of women at risk of developing a hypertensive disorder, who could thus benefit from a preventive treatment, as aspirin.

Sick genes, sick individuals or sick populations with chronic disease? The emergence of diabetes and high blood pressure in African-origin populations

AIM AND METHODS

To discuss evidence for and against genetic 'causes' of type 2 diabetes, illustrated by standardized study of glucose intolerance and high blood pressure in four representative African origin populations. Comparison of two genetically closer sites: rural (site 1) and urban Cameroon (2); then Jamaica (3) and Caribbean migrants to Britain (80% from Jamaica-4).

BACKGROUND

Alternatives to the reductionist search for genetic 'causes' of chronic disease include Rose's concept that populations give rise to 'sick' individuals. Twin studies offer little support to genetic hypotheses because monozygotic twins share more than genes in utero and suffer from ascertainment bias. Non-genetic intergenerational mechanisms include amniotic fluid growth factors and maternal exposures. Type 2 diabetes and hypertension incidence accelerate in low-risk European populations from body mass > or =23 kg/m2, well within 'desirable' limits. Transition from subsistence agriculture in West Africa occurred this century and from western hemisphere slavery only six generations ago, with slow escape from intergenerational poverty since.

RESULTS

'Caseness' increased clearly within and between genetically similar populations: age-adjusted diabetes rates were 0.8, 2.4, 8.5 and 16.4% for sites 1-4, respectively; for 'hypertension', rates were 7, 16, 21 and 34%, with small shifts in risk factors. Body mass index rose similarly.

CONCLUSION

Energy imbalance and intergenerational socioeconomic influences are much more likely causes of diabetes (and most chronic disease) than ethnic/genetic variation, which does occur, poorly related to phenotype. The newer method of 'proteomics' holds promise for identifying environmental triggers influencing gene products. Even in lower prevalence 'westernized' societies, genetic screening per se for diabetes/chronic disease is likely to be imprecise and inefficient hence unreliable and expensive.

Prevention of pre-eclampsia: status and perspectives 2000

Because pre-eclampsia is a relatively common complication of pregnancy and forms a major cause of maternal, fetal, and neonatal morbidity and mortality, attempts at prevention are justified, but hampered by the fact that as yet no reliable and acceptable screening tests for women at risk are available. Analysis of the many interventions advocated to prevent or delay the onset of pre-eclampsia reveals that dietary calcium supplementation and prophylactic low-dose aspirin treatment have shown promise of efficacy in small randomized, placebo-controlled trials, but the results of large, multicenter trials are generally disappointing. The disappointing results obtained in large, multicenter trials may in part be explained by the lack of strict criteria for inclusion, late initiation of treatment, use of ill-defined end points, different timing of aspirin ingestion, and low patient compliance. Recent evidence that supplementation with vitamins C and E could prevent pre-eclampsia awaits confirmation. Future clinical trials on prevention of pre-eclampsia should be based on results of basic research.

How effective is antenatal care in preventing maternal mortality and serious morbidity? An overview of the evidence

This is an overview of evidence of the effectiveness of antenatal care in relation to maternal mortality and serious morbidity, focused in particular on developing countries. It concentrates on the major causes of maternal mortality, and traces their antecedent morbidities and risk factors in pregnancy. It also includes interventions aimed at preventing, detecting or treating any stage along this pathway during pregnancy. This is an updated and expanded version of a review first published by the World Health Organization (WHO) in 1992. The scientific evidence from randomised controlled trials and other types of intervention or observational study on the effectiveness of these interventions is reviewed critically. The sources and quality of available data, and possible biases in their collection or interpretation are considered. As in other areas of maternal health, good-quality evidence is scarce and, just as in many aspects of health care generally, there are interventions in current practice that have not been subjected to rigorous evaluation. A table of antenatal interventions of proven effectiveness in conditions that can lead to maternal mortality or serious morbidity is presented. Interventions for which there is some promising evidence, short of proof, of effectiveness are explored, and the outstanding questions formulated. These are presented in a series of tables with suggestions about the types of study needed to answer them.