Low dose aspirin for the treatment of fetal growth restriction: a randomized controlled trial

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prenatal interventions for fetal growth restriction in animal models: A systematic review

Fetal growth restriction (FGR) in human pregnancy is associated with perinatal mortality, short- and long-term morbidities. No prenatal therapy is currently established despite decades of research. We aimed to review interventions in animal models for prenatal FGR treatment, and to seek the next steps for an effective clinical therapy. We registered our protocol and searched MEDLINE, Embase, and The Cochrane Library with no language restrictions, in accordance with the PRISMA guideline. We included all studies that reported the effects of any prenatal intervention in animal models of induced FGR. From 3257 screened studies, 202 describing 237 interventions were included for the final synthesis. Mice and rats were the most used animals (79%) followed by sheep (16%). Antioxidants (23%), followed by vasodilators (18%), nutrients (14%), and immunomodulators (12%) were the most tested therapy. Two-thirds of studies only reported delivery or immediate neonatal outcomes. Adverse effects were rarely reported (11%). Most studies (73%), independent of the intervention, showed a benefit in fetal survival or birthweight. The risk of bias was high, mostly due to the lack of randomization, allocation concealment, and blinding. Future research should aim to describe both short- and long-term outcomes across various organ systems in well-characterized models. Further efforts must be made to reduce selection, performance, and detection bias.

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

CONTEXT

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSIONS

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

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

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

Maternal low molecular weight heparin versus sildenafil citrate for fetal growth restriction: a randomized, parallel groups, open-label clinical trial

OBJECTIVES

To compare the effect of sildenafil citrate (SC) and low molecular weight heparin (LMWH) on neonatal birth weight (BW) and the fetoplacental blood flow in pregnancies with FGR.

STUDY DESIGN

A parallel groups, randomized clinical trial was conducted at a university hospital, between June 2017 and September 2018, involving 100 pregnant women with placental mediated FGR between 28 and 35 weeks of gestation who were randomly assigned to receive either SC or LMWH started at FGR diagnosis till delivery.

RESULTS

The neonatal BW in LMWH group was higher than SC group (p < 0.000) with a longer time from randomization till delivery, LMWH group had significant improvement in Ut A PI, UA PI, and MCA PI compared with SC treated group with p values 0.005, <0.000001, and 0.014, respectively.

CONCLUSION

The neonatal BW, time from randomization to delivery, and fetoplacental blood flow indices were significantly better with LMWH use compared with SC.

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.

Variation in outcome reporting in randomized controlled trials of interventions for prevention and treatment of fetal growth restriction

OBJECTIVE

Although fetal growth restriction (FGR) is well known to be associated with adverse outcomes for the mother and offspring, effective interventions for the management of FGR are yet to be established. Trials reporting interventions for the prevention and treatment of FGR may be limited by heterogeneity in the underlying pathophysiology. The aim of this study was to conduct a systematic review of outcomes reported in randomized controlled trials (RCTs) assessing interventions for the prevention or treatment of FGR, in order to identify and categorize the variation in outcome reporting.

METHODS

MEDLINE, EMBASE and The Cochrane Library were searched from inception until August 2018 for RCTs investigating therapies for the prevention and treatment of FGR. Studies were assessed systematically and data on outcomes that were reported in the included studies were extracted and categorized. The methodological quality of the included studies was assessed using the Jadad score.

RESULTS

The search identified 2609 citations, of which 153 were selected for full-text review and 72 studies (68 trials) were included in the final analysis. There were 44 trials relating to the prevention of FGR and 24 trials investigating interventions for the treatment of FGR. The mean Jadad score of all studies was 3.07, and only nine of them received a score of 5. We identified 238 outcomes across the included studies. The most commonly reported were birth weight (88.2%), gestational age at birth (72.1%) and small-for-gestational age (67.6%). Few studies reported on any measure of neonatal morbidity (27.9%), while adverse effects of the interventions were reported in only 17.6% of trials.

CONCLUSIONS

There is significant variation in outcome reporting across RCTs of therapies for the prevention and treatment of FGR. The clinical applicability of future research would be enhanced by the development of a core outcome set for use in future trials. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Intrauterine Growth Restriction. Guideline of the German Society of Gynecology and Obstetrics (S2k-Level, AWMF Registry No. 015/080, October 2016)

AIMS

The aim of this official guideline published and coordinated by the German Society of Gynecology and Obstetrics (DGGG) was to provide consensus-based recommendations obtained by evaluating the relevant literature for the diagnostic treatment and management of women with fetal growth restriction.

METHODS

This S2k guideline represents the structured consensus of a representative panel of experts with a range of different professional backgrounds commissioned by the Guideline Committee of the DGGG.

RECOMMENDATIONS

Recommendations for diagnostic treatment, management, counselling, prophylaxis and screening are presented.

The effect of low-dose aspirin on fetal weight of idiopathic asymmetrically intrauterine growth restricted fetuses with abnormal umbilical artery Doppler indices: a randomized clinical trial

OBJECTIVE

To investigate the effect of aspirin on fetal weight in fetuses with idiopathic asymmetrical intrauterine growth restriction (IUGR) complicated by abnormal umbilical artery Doppler indices.

MATERIALS AND METHODS

The study was a randomized controlled trial conducted at Woman's Health Hospital, Assiut, Egypt, between June 2016 and the January 2017 included 60 pregnant women (28-30 weeks) with idiopathic asymmetrical IUGR associated with abnormal umbilical artery Doppler indices. Women were randomly assigned to group I (aspirin 75 mg) daily for four weeks or group II (no intervention). The primary outcome was the fetal weight after four weeks. Secondary outcomes included Doppler blood flow changes in the umbilical artery plus delivery and neonatal outcomes.

RESULTS

The estimated fetal weight and umbilical artery blood flow increased significantly in aspirin group (p = .00) when compared with no intervention group. As regard neonatal outcomes; aspirin group showed better results and encouraging outcomes (p < .05).

CONCLUSIONS

Aspirin improves fetal weight and umbilical artery blood flow in idiopathic asymmetrical IUGR fetuses complicated by abnormal umbilical artery Doppler blood flow.

A description of the methods of the aspirin supplementation for pregnancy indicated risk reduction in nulliparas (ASPIRIN) study

Background

Preterm birth (PTB) remains the leading cause of neonatal mortality and long term disability throughout the world. Though complex in its origins, a growing body of evidence suggests that first trimester administration of low dose aspirin (LDA) may substantially reduce the rate of PTB.

Methods

Hypothesis: LDA initiated in the first trimester reduces the risk of preterm birth.

Study Design Type: Prospective randomized, placebo-controlled, double-blinded multi-national clinical trial conducted in seven low and middle income countries. Trial will be individually randomized with one-to-one ratio (intervention/control)

Population: Nulliparous women between the ages of 14 and 40, with a singleton pregnancy between 6 0/7 weeks and 13 6/7 weeks gestational age (GA) confirmed by ultrasound prior to enrollment, no more than two previous first trimester pregnancy losses, and no contraindications to aspirin.

Intervention: Daily administration of low dose (81 mg) aspirin, initiated between 6 0/7 weeks and 13 6/7 weeks GA and continued to 36 0/7 weeks GA, compared to an identical appearing placebo. Compliance and outcomes will be assessed biweekly.

Outcomes

Primary outcome: Incidence of PTB (birth prior to 37 0/7 weeks GA).

Secondary outcomes Incidence of preeclampsia/eclampsia, small for gestational age and perinatal mortality.

Discussion

This study is unique as it will examine the impact of LDA early in pregnancy in low-middle income countries with preterm birth as a primary outcome. The importance of developing low-cost, high impact interventions in low-middle income countries is magnified as they are often unable to bear the financial costs of treating illness.

Trial registration

ClinicalTrials.gov identifier: NCT02409680 Date: March 30, 2015

Placental soluble fms-like tyrosine kinase expression in small for gestational age infants and risk for adverse outcomes

INTRODUCTION

Soluble fms-like tyrosine kinase 1 (sFLT-1) is an anti-angiogenic factor implicated in the pathogenesis of preterm preeclampsia. We evaluated sFLT-1 expression and placental pathology in pregnancies complicated by small for gestational age (SGA) infants (<10th percentile), without evidence of preeclampsia.

METHODS

Clinical and histologic data were compared between groups with high or low sFLT-1 expression determined by immunohistochemistry on archived placentas.

RESULTS

Nineteen of 69 placentas showed high sFLT-1 expression. The high sFLT-1 group had higher predelivery median systolic blood pressure (BP); 140 (interquartile range (IQR) 133-152) vs. 126 (118-139) mm Hg (p = 0.003), and median diastolic BP; 87 (78-94) vs. 77.5 (71-86) mm Hg (p = 0.02). Abnormal umbilical Doppler abnormalities were more prevalent; 89.5% vs. 46% (p = 0.001). These pregnancies delivered earlier; 31.9 weeks (28.3-34.7 weeks) vs. 37.1 weeks (33.7-38.7 weeks) (p < 0.001), and infants had lower birthweight; 980 grams (520-1545 grams) vs. 2087.5 grams (1455-2340 grams) (p < 0.001). Placental-weight to fetal-weight ratios, a marker of vascular insufficiency, was increased in the high sFlt-1 group: 0.18 (0.14-0.28) vs 0.15 (0.13-0.18), p = 0.03. Placentas with high sFLT-1 showed more decidual vasculopathy; 42.1% vs. 10.0% (p = 0.005), infarction; 36.8% vs. 14.0% (p = 0.048), distal villous hypoplasia; 78.9% vs. 36.0% (p = 0.001), and fetal thrombotic vasculopathy; 47.4% vs. 16.0% (p = 0.01).

DISCUSSION

Placental sFLT-1 expression is upregulated in approximately 28% of non-preeclamptic pregnancies complicated by SGA infants. These pregnancies showed increased placental vascular pathology, more umbilical Doppler abnormalities, and earlier delivery with lower birthweight. A subgroup of non-preeclamptic fetal growth restriction with upregulated sFlt-1 expression may share a common pathogenic pathway with preterm preeclampsia. This subgroup is worthy of additional study.

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

BACKGROUND

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Role for the thromboxane A2 receptor β-isoform in the pathogenesis of intrauterine growth restriction

Intrauterine growth restriction (IUGR) is a pathology of pregnancy that results in failure of the fetus to reach its genetically determined growth potential. In developed nations the most common cause of IUGR is impaired placentation resulting from poor trophoblast function, which reduces blood flow to the fetoplacental unit, promotes hypoxia and enhances production of bioactive lipids (TXA₂ and isoprostanes) which act through the thromboxane receptor (TP). TP activation has been implicated as a pathogenic factor in pregnancy complications, including IUGR; however, the role of TP isoforms during pregnancy is poorly defined. We have determined that expression of the human-specific isoform of TP (TPβ) is increased in placentae from IUGR pregnancies, compared to healthy pregnancies. Overexpression of TPα enhanced trophoblast proliferation and syncytialisation. Conversely, TPβ attenuated these functions and inhibited migration. Expression of the TPβ transgene in mice resulted in growth restricted pups and placentae with poor syncytialisation and diminished growth characteristics. Together our data indicate that expression of TPα mediates normal placentation; however, TPβ impairs placentation, and promotes the development of IUGR, and represents an underappreciated pathogenic factor in humans.

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.

Docosahexaenoic acid supplementation early in pregnancy may prevent deep placentation disorders

Uteroplacental ischemia may cause preterm birth, either due to preterm labor, preterm premature rupture of membranes, or medical indication (in the presence of preeclampsia or fetal growth restriction). Uteroplacental ischemia is the product of defective deep placentation, a failure of invasion, and transformation of the spiral arteries by the trophoblast. The failure of normal placentation generates a series of clinical abnormalities nowadays called "deep placentation disorders"; they include preeclampsia, fetal growth restriction, preterm labor, preterm premature rupture of membranes, in utero fetal death, and placental abruption. Early reports suggested that a LC-PUFAs (long chain polyunsaturated fatty acids) rich diet reduces the incidence of deep placentation disorders. Recent randomized controlled trials are inconsistent to show the benefit of docosahexaenoic acid (DHA) supplementation during pregnancy to prevent deep placentation disorders, but most of them showed that DHA supplementation was associated with lower risk of early preterm birth. We postulate that DHA supplementation, early in pregnancy, may reduce the incidence of deep placentation disorders. If our hypothesis is correct, DHA supplementation, early in pregnancy, will become a safe and effective strategy for primary prevention of highly relevant pregnancy diseases, such as preterm birth, preeclampsia, and fetal growth restriction.

Creatine supplementation during pregnancy: summary of experimental studies suggesting a treatment to improve fetal and neonatal morbidity and reduce mortality in high-risk human pregnancy

While the use of creatine in human pregnancy is yet to be fully evaluated, its long-term use in healthy adults appears to be safe, and its well documented neuroprotective properties have recently been extended by demonstrations that creatine improves cognitive function in normal and elderly people, and motor skills in sleep-deprived subjects. Creatine has many actions likely to benefit the fetus and newborn, because pregnancy is a state of heightened metabolic activity, and the placenta is a key source of free radicals of oxygen and nitrogen. The multiple benefits of supplementary creatine arise from the fact that the creatine-phosphocreatine [PCr] system has physiologically important roles that include maintenance of intracellular ATP and acid–base balance, post-ischaemic recovery of protein synthesis, cerebral vasodilation, antioxidant actions, and stabilisation of lipid membranes. In the brain, creatine not only reduces lipid peroxidation and improves cerebral perfusion, its interaction with the benzodiazepine site of the GABA_A receptor is likely to counteract the effects of glutamate excitotoxicity – actions that may protect the preterm and term fetal brain from the effects of birth hypoxia. In this review we discuss the development of creatine synthesis during fetal life, the transfer of creatine from mother to fetus, and propose that creatine supplementation during pregnancy may have benefits for the fetus and neonate whenever oxidative stress or feto-placental hypoxia arise, as in cases of fetal growth restriction, premature birth, or when parturition is delayed or complicated by oxygen deprivation of the newborn.

A randomised trial to evaluate the effects of low-dose aspirin in gestation and reproduction: design and baseline characteristics

BACKGROUND

Low-dose aspirin (LDA) has been proposed to improve pregnancy outcomes in couples experiencing recurrent pregnancy loss. However, results from studies of LDA on pregnancy outcomes have been inconsistent, perhaps because most studies evaluated LDA-initiated post-conception. The purpose of the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial was to determine whether preconception-initiated LDA improves livebirth rates in women with one to two prior losses.

METHODS

We performed a multicentre, block randomised, double-blind, placebo-controlled trial. Study participants were recruited using community-based advertisements and physician referral to four university medical centres in the US (2006-12). Eligible women were aged 18-40 years actively trying to conceive, with one to two prior losses. Participants were randomised to receive daily LDA (81 mg/day) or a matching placebo, and all were provided with daily 400-mcg folic acid. Follow-up continued for ≤6 menstrual cycles while attempting to conceive. For those who conceived, treatment was continued until 36 weeks gestation. The primary outcome was the cumulative livebirth rate over the trial period.

RESULTS

There were 1228 women randomised (615 LDA, 613 placebo). Participants had a mean age of 28.7, were mostly white (95%), well educated (86% more than high school education), and employed (75%) with a household income >$100 000 annually (40%). The characteristics of those in the treatment and placebo arms were well balanced.

CONCLUSIONS

We describe the study design, recruitment, data collection, and baseline characteristics of participants enrolled in EAGeR, which aimed to determine the effect of LDA on livebirth and other pregnancy outcomes in these women.

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.

Hematologic profile of neonates with growth restriction is associated with rate and degree of prenatal Doppler deterioration

OBJECTIVE

To examine the relationship between hematologic parameters at birth and prenatal progression of Doppler abnormalities in fetal growth restriction (FGR).

METHODS

The study was a secondary analysis of FGR patients (abdominal circumference < 5th percentile and umbilical artery pulsatility index (UA-PI) elevation) with at least three examinations prior to delivery. Prenatal progression was classified as rapid, moderate or slow based on the interval between diagnosis and delivery and the extent of UA, middle cerebral artery and ductus venosus Doppler abnormalities. Associations between diagnosis-to-delivery interval, Doppler Z-scores, progression and hematologic parameters at birth were examined.

RESULTS

Of 130 patients, 54 (41.5%) had rapid, 51 (39.2%) moderate and 25 (19.2%) slow deterioration, delivering within 4, 6 and 9 weeks of diagnosis, respectively. The strongest association of moderate and rapid deterioration was with a low platelet count (r2  = 0.37 and 0.70, respectively; P < 0.0001). In patients with moderate deterioration, platelet count correlated inversely with UA-PI (ρ = -0.44, P = 0.001) and was lowest when end-diastolic velocity was absent. With rapid progression, platelet count correlated inversely with nucleated red blood cell count (ρ = -0.51, P < 0.001) but no longer with UA-PI.

CONCLUSION

Our observations suggest a relationship between prenatal clinical progression of FGR and hematologic abnormalities at birth. Accelerating cardiovascular deterioration is associated with decreased platelet count, which can be explained by placental consumption or dysfunctional erythropoiesis and thrombopoiesis.

Intrauterine growth restriction: comparison of American College of Obstetricians and Gynecologists practice bulletin with other national guidelines

OBJECTIVE

The objective of the study was to compare national guidelines regarding small for gestational age (SGA).

STUDY DESIGN

Along with American College of Obstetricians and Gynecologists (ACOG) practice bulletin on abnormal growth, guidelines from England, Canada, Australia, and New Zealand were reviewed.

RESULTS

There are no guidelines on SGA from Canada, Australia, and New Zealand. The Royal College of Obstetricians and Gynaecologists (RCOG) guideline agrees with ACOG's definition of abnormal growth, but there are noticeable variances in the diagnosis and management of SGA. RCOG has more recommendations than ACOG (18 vs 4, respectively). The articles referenced varied, with only 13 similar articles being cited by the both committees.

CONCLUSION

The differences in the 2 guidelines suggest that there is variance in how 2 committees synthesize the literature and issue recommendations.

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 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.

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.

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 asprin 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.

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 should be started, and at what dose.

Administration of low-dose aspirin to mothers with small for gestational age fetuses and abnormal umbilical Doppler studies to increase birthweight: a randomised double-blind controlled trial

OBJECTIVE

To determine whether antenatal treatment (for > or = 14 days) with 100 mg aspirin daily, given to mothers with small for gestational age fetuses and abnormal umbilical Doppler, will increase birthweight.

DESIGN

Randomised, double-blind placebo controlled trial.

SETTING

A tertiary referral centre.

PARTICIPANTS

Ninety-nine women, of whom 65 were treated for > or = 14 days (32 with aspirin and 33 with placebo) and comprised the study group. The entry criteria were: singleton pregnancy with ultrasound evidence of a small for gestational age fetus (abdominal circumference < 10%); previous anatomy scan < 20 weeks and no evidence of fetal abnormality; gestation between 24 and 36 weeks; umbilical artery Doppler resistance index > 95% for gestation; no previous aspirin treatment in pregnancy; and no contra-indication to aspirin treatment.

RESULTS

The mean duration of treatment was 30 days for aspirin treated, and 29 for placebo. No difference was found in birthweight or other measures of fetal growth or newborn morbidity between those treated with aspirin or placebo. Compliance, assessed by thromboxane B2 analysis, showed almost complete suppression of thromboxane B2 in aspirin treated women.

CONCLUSION

Low-dose aspirin did not increase birthweight in pregnancies where the fetus has abnormal umbilical Doppler and is thought to be small for gestational age.