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

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

Background

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

Methods/Design

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

Hypertension in diabetic pregnancy: impact and long-term outlook

Hypertensive disorders in pregnancy can be chronic, pregestational or just diagnosed before the 20th week, or newly diagnosed in the second half of pregnancy. Any type of hypertension is more frequent in diabetic pregnancies with a different distribution among different types of diabetes. Most of the evidence is for pre-eclampsia associated with a marked increase in primary caesarean section, preterm birth and more need for neonatal intensive care. Different risk factors and pregnancy outcomes would support the hypothesis that pre-eclampsia and gestational hypertension might be largely separate entities, but this position is not unanimously accepted. Chronic hypertension increases with age and duration of diabetes, predicting increased rates of prematurity and neonatal morbidity, especially when associated with superimposed pre-eclampsia. Long-term consequences are observed in women whose pregnancy was complicated by hypertension such as chronic hypertension and cardiovascular diseases.

Hypertension in pregnancy

Hypertension complicates 5% to 7% of all pregnancies. A subset of preeclampsia, characterized by new-onset hypertension, proteinuria, and multisystem involvement, is responsible for substantial maternal and fetal morbidity and is a marker for future cardiac and metabolic disease. This American Society of Hypertension (ASH) position paper summarizes the clinical spectrum of hypertension in pregnancy, focusing on preeclampsia. Recent research breakthroughs relating to etiology are briefly reviewed. Topics include classification of the different forms of hypertension during pregnancy, and status of the tests available to predict preeclampsia, and strategies to prevent preeclampsia and to manage this serious disease. The use of antihypertensive drugs in pregnancy, and the prevention and treatment of the convulsive phase of preeclampsia, eclampsia, with intravenous MgSO(4) is also highlighted. Of special note, this guideline article, specifically requested, reviewed, and accepted by ASH, includes solicited review advice from the American College of Obstetricians and Gynecologists.

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.

Vitamins C and E to prevent complications of pregnancy-associated hypertension

BACKGROUND

Oxidative stress has been proposed as a mechanism linking the poor placental perfusion characteristic of preeclampsia with the clinical manifestations of the disorder. We assessed the effects of antioxidant supplementation with vitamins C and E, initiated early in pregnancy, on the risk of serious adverse maternal, fetal, and neonatal outcomes related to pregnancy-associated hypertension.

METHODS

We conducted a multicenter, randomized, double-blind trial involving nulliparous women who were at low risk for preeclampsia. Women were randomly assigned to begin daily supplementation with 1000 mg of vitamin C and 400 IU of vitamin E or matching placebo between the 9th and 16th weeks of pregnancy. The primary outcome was severe pregnancy-associated hypertension alone or severe or mild hypertension with elevated liver-enzyme levels, thrombocytopenia, elevated serum creatinine levels, eclamptic seizure, medically indicated preterm birth, fetal-growth restriction, or perinatal death.

RESULTS

A total of 10,154 women underwent randomization. The two groups were similar with respect to baseline characteristics and adherence to the study drug. Outcome data were available for 9969 women. There was no significant difference between the vitamin and placebo groups in the rates of the primary outcome (6.1% and 5.7%, respectively; relative risk in the vitamin group, 1.07; 95% confidence interval [CI], 0.91 to 1.25) or in the rates of preeclampsia (7.2% and 6.7%, respectively; relative risk, 1.07; 95% CI, 0.93 to 1.24). Rates of adverse perinatal outcomes did not differ significantly between the groups.

CONCLUSIONS

Vitamin C and E supplementation initiated in the 9th to 16th week of pregnancy in an unselected cohort of low-risk, nulliparous women did not reduce the rate of adverse maternal or perinatal outcomes related to pregnancy-associated hypertension (ClinicalTrials.gov number, NCT00135707).

ASH position paper: hypertension in pregnancy

The American Society of Hypertension is publishing a series of Position Papers in their official journals throughout the 2008-2009 years. The following Position Paper originally appeared: JASH. 2008;2(6):484-494. Hypertension complicates 5% to 7% of all pregnancies. A subset of preeclampsia, characterized by new-onset hypertension, proteinuria, and multisystem involvement, is responsible for substantial maternal and fetal morbidity and is a marker for future cardiac and metabolic disease. This American Society of Hypertension, Inc (ASH) position paper summarizes the clinical spectrum of hypertension in pregnancy, focusing on preeclampsia. Recent research breakthroughs relating to etiology are briefly reviewed. Topics include classification of the different forms of hypertension during pregnancy, status of the tests available to predict preeclampsia, and strategies to prevent preeclampsia and to manage this serious disease. The use of antihypertensive drugs in pregnancy, and the prevention and treatment of the convulsive phase of preeclampsia, eclampsia, with intravenous magnesium sulfate is also highlighted. Of special note, this guideline article, specifically requested, reviewed, and accepted by ASH, includes solicited review advice from the American College of Obstetricians and Gynecologists.

Is there a seasonal variation in the diagnosis of oligohydramnios?

OBJECTIVE

We hypothesized that oligohydramnios would be diagnosed more frequently in the warm summer months when dehydration might be more common.

METHODS

The clinical diagnosis of oligohydramnios was extracted from the databases of four completed National Institute of Child Health and Human Development Maternal Fetal Medicine Units Network protocols. These data were stratified by quarter of delivery and compared using Fisher's Exact Test.

RESULTS

The clinical diagnosis of oligohydramnios was made more frequently in deliveries occurring in the summer months of June, July and August as compared with the remainder of the calendar year (7.2% vs 5.9%, p=0.0178).

CONCLUSIONS

In these studies the diagnosis of oligohydramnios is made more frequently in those pregnancies delivered during the summer months. Although not proven by this association, maternal dehydration may contribute to this finding.

Severe Preeclampsia is Associated with a Positive Family History of Hypertension and Hypercholesterolemia

OBJECTIVE

To investigate an association between a family history of cardiovascular disease and severe preeclampsia and/or HELLP syndrome (Haemolysis, Elevated Liver enzymes, Low Platelets).

METHODS

One hundred twenty-eight women with a history of severe preeclampsia and/or HELLP syndrome and 123 women with previous uncomplicated pregnancies only were included in the study. All participants completed questionnaires about diagnoses of cardiovascular diseases, hypertension, and hypercholesterolemia among their first-degree relatives, which were subsequently confirmed by the relatives' general practitioners. The main outcome measures were the prevalence of cardiovascular diseases, hypertension, and hypercholesterolemia among first-degree relatives of both groups. Statistical analysis was done using chi(2)-analysis.

RESULTS

The prevalence of familial cardiovascular disease among women with a history of severe preeclampsia and/or HELLP syndrome (23%) compared to controls (19%) was not significantly different (OR 1.3, 95%CI 0.7-2.5). However, women with a history of severe preeclampsia and/or HELLP syndrome more often had one or more first-degree relatives with hypertension and/or hypercholesterolemia before the age of 60 years compared to controls (54% vs. 32%, respectively; OR 2.6, 95%CI 1.5-4.3). The prevalence of hypertension and hypercholesterolemia among first-degree relatives, irrespective of age, also was significantly higher among women with a history of severe preeclampsia and/or HELLP syndrome as compared to controls (60% vs. 42%, respectively; OR 2.0, 95%CI 1.2-3.4).

CONCLUSION

Severe preeclampsia is associated with a positive family history of hypertension and/or hypercholesterolemia.

Goals and strategies for prevention of preterm birth: an obstetric perspective

Complications of prematurity surpass congenital malformations as the leading cause of infant mortality in the United States. Since 1990, there has been a steady rise in preterm birth, alarming health professionals from all disciplines. This review from a prenatal perspective confirms those concerns and describes the risks and opportunities that may attend efforts to improve the health of fetuses, newborns, and infants. Fetal and live-born outcomes are included.

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.

ASH position paper: hypertension in pregnancy

The American Society of Hypertension is publishing a series of Position Papers in their official journals throughout the 2008-2009 years. The following Position Paper originally appeared: JASH. 2008;2(6):484-494. Hypertension complicates 5% to 7% of all pregnancies. A subset of preeclampsia, characterized by new-onset hypertension, proteinuria, and multisystem involvement, is responsible for substantial maternal and fetal morbidity and is a marker for future cardiac and metabolic disease. This American Society of Hypertension, Inc (ASH) position paper summarizes the clinical spectrum of hypertension in pregnancy, focusing on preeclampsia. Recent research breakthroughs relating to etiology are briefly reviewed. Topics include classification of the different forms of hypertension during pregnancy, status of the tests available to predict preeclampsia, and strategies to prevent preeclampsia and to manage this serious disease. The use of antihypertensive drugs in pregnancy, and the prevention and treatment of the convulsive phase of preeclampsia, eclampsia, with intravenous magnesium sulfate is also highlighted. Of special note, this guideline article, specifically requested, reviewed, and accepted by ASH, includes solicited review advice from the American College of Obstetricians and Gynecologists.

Medical issues from preconception through delivery: a roadmap for the internist

The age of the pregnant population and the number of pregnant women with medical issues are increasing. It is widely recognized that internists have the unique opportunity to identify potential pregnancy issues and address them before a problem arises. Therefore, it's important that we become aware of how to approach these issues. In addition to addressing medical issues in a currently pregnant woman, doctors also have the opportunity to identify issues that occurred during a prior pregnancy, such as gestational diabetes, preeclampsia, or pregnancy loss, and to decrease the risk of complications in future pregnancies. The goal of this article is to provide a roadmap to practicing internists so they will incorporate pregnancy planning into their everyday care plans. The approach is similar to that used when performing a preoperative risk assessment: We want to optimize our patients medically for pregnancy.

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.

The influence of obstetric practices on late prematurity

In this article, the authors review the standard management of several maternal and fetal complications of pregnancy and examine the effect these practices may have on the late preterm birth rate. Given the increasing rate of late preterm birth and the increased recognition of the morbidity and mortality associated with delivery between 34 and 37 weeks, standard obstetric practices and practice patterns leading to late preterm birth should be critically evaluated. The possibility of expectant management of some pregnancy complications in the late preterm period should be investigated. Furthermore, prospective research is warranted to investigate the role of antenatal corticosteroids beyond 34 weeks.

Primary, secondary, and tertiary interventions to reduce the morbidity and mortality of preterm birth

Interventions to reduce the morbidity and mortality of preterm birth can be primary (directed to all women), secondary (aimed at eliminating or reducing existing risk), or tertiary (intended to improve outcomes for preterm infants). Most efforts so far have been tertiary interventions, such as regionalised care, and treatment with antenatal corticosteroids, tocolytic agents, and antibiotics. These measures have reduced perinatal morbidity and mortality, but the incidence of preterm birth is increasing. Advances in primary and secondary care, following strategies used for other complex health problems, such as cervical cancer, will be needed to prevent prematurity-related illness in infants and children.

Inherited thrombophilias and pre-eclampsia in Brazilian women

OBJECTIVE

The aim of the present study was to compare the distribution of G1691A, G20210A and C677T mutations in pre-eclamptic Brazilian women and in matched control women with an uncomplicated normal pregnancy.

STUDY DESIGN

these mutations were investigated by PCR-RFLP in 83 normal pregnancies (control group) and in 30 pre-eclamptic pregnant women (severe form).

RESULTS

G1691A mutation was detected neither in the control group nor in pre-eclamsia women. G20210A mutation was detected in heterozygosis in 3 (3.61%) control subjects, but not in pre-eclampsia group. C677T mutation was detected in homozygosis in 6 (7.23%) control subjects and 2 (6.67%) pre-eclamptic women and in heterozygosis in 31 (37.3%) control subjects and 12 (40%) pre-eclamptic women. Differences in the mutation frequencies detected in the two groups were not statistically significant.

CONCLUSION

No correlation was observed between pre-eclampsia and presence of G1691A, G20210A and C677T mutations in Brazilian women.

Second-trimester angiogenic factors as biomarkers for future-onset preeclampsia

OBJECTIVE

The purpose of this study was to determine whether second-trimester soluble fms-like tyrosine kinase-1 and placenta growth factor (PlGF) are altered in patients who have preeclampsia develop compared with controls. Furthermore, soluble fms-like tyrosine kinase-1 and placenta growth factor levels in patients with chronic hypertension are described.

STUDY DESIGN

With the use of a research database, 21 patients who had severe preeclampsia develop, 34 controls, and 9 patients with chronic hypertension were enrolled. Placenta growth factor and soluble fms-like tyrosine kinase-1 serum levels were determined by enzyme-linked immunosorbent assay. Appropriate statistical tests were used and results were reported as median (quartile 1-quartile 3) in picograms per milliliter.

RESULTS

Placenta growth factor was significantly lower in patients in the second trimester who later had severe preeclampsia develop but soluble fms-like tyrosine kinase-1 was unchanged compared with healthy pregnancies. In patients with chronic hypertension, placenta growth factor and soluble fms-like tyrosine kinase-1 levels were not different compared with controls.

CONCLUSION

Second-trimester placenta growth factor levels are altered in patients who had severe preeclampsia develop.

Subgroup analysis in obstetrics clinical trials

Although clinical trials report results in the aggregate, clinicians often wish to tailor treatments that are based on demographic, historic, clinical, or laboratory characteristics of their patients and are interested therefore in trial results that are presented separately according to such characteristics. Unfortunately, such subgroup analysis often are done incorrectly and often are misinterpreted, even when done correctly. Only subgroups that are defined by characteristics that are determined at or before the moment of randomization are valid. It is incorrect to determine whether treatment is effective among a subgroup of patients according to the probability value in that particular subgroup. The correct method uses a formal test for interaction. However, even when done correctly, most subgroup differences in treatment effectiveness prove to be spurious. A priori definition of the subgroup, strong supporting rationale, and, ultimately, replication in other studies increase confidence that subgroup differences are valid.

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.

Prepregnancy Body Mass Index and the Occurrence of Severe Hypertensive Disorders of Pregnancy

BACKGROUND

Prepregnancy overweight is a risk factor for mild preeclampsia and mild transient hypertension of pregnancy. Its association with severe subtypes of these disorders has received less attention.

METHODS

To assess the association of prepregnancy body mass index (BMI) with severe and mild preeclampsia and transient hypertension of pregnancy, we used data from a 1958-1964 prospective cohort study of 38,188 pregnant women receiving care at 12 U.S. hospitals.

RESULTS

There was a monotonic, dose-response relation between prepregnancy BMI and risk of both severe and mild preeclampsia, as well as the risk of severe and mild transient hypertension of pregnancy. Compared with white women with a BMI of 20, the odds ratios for severe preeclampsia at BMI values of 25 and 30 in white women were 1.7 (95% confidence interval = 1.1-2.5) and 3.4 (2.1-5.6), respectively, and 2.1 (1.4-3.2) and 3.2 (2.1-5.0) in black women. The effect of BMI on risk of severe preeclampsia was similar to its effect on mild disease. Compared with the same referent, odds ratios for severe transient hypertension of pregnancy at BMI values of 25 and 30 in white women were 3.6 (2.0-6.5) and 8.8 (4.4-18), respectively, and 3.0 (1.6-5.8) and 4.9 (2.5-9.6) in black women. Overweight was a stronger risk factor for severe than for mild transient hypertension.

CONCLUSIONS

Incidence of both mild and severe hypertensive disorders of pregnancy rises with increasing BMI. Escalating obesity rates may increase pregnancy hypertensive disorders and ensuing perinatal morbidity.

Pathophysiology and medical management of systemic hypertension in preeclampsia

Hypertension that complicates preeclampsia in pregnancy is a disorder that requires special consideration in both prevention and pharmacologic treatment. In recent years, few advances have been made regarding the pathophysiology and prevention of preeclampsia; however, there have been some promising results from studies on possible modes of screening women for preeclampsia before clinical signs and symptoms are apparent. The recommendations for first-line drug therapy for the hypertensive complications of preeclampsia have changed little, primarily because first-line medications have had the advantage of extensive research experience. Recent clinical trials have demonstrated the efficacy and safety of various second-line drugs for the hypertensive complications of preeclampsia; whether these therapies can eventually replace the standard recommended first-line medications will require more extensive long-term investigation.

Hypoxia and Reoxygenation: a Possible Mechanism for Placental Oxidative Stress in Preeclampsia

Preeclampsia is a human pregnancy-specific disorder that is diagnosed by the new appearance of hypertension and proteinuria after 20 weeks' gestation. It is a leading cause of perinatal morbidity and mortality, and the only intervention that effectively reverses the syndrome is delivery. Oxidative stress of the placenta is considered to be a key intermediary step in the pathogenesis of preeclampsia, but the cause for the stress remains unknown. Hypoxia-reoxygenation (H/R) injury, as a result of intermittent placental perfusion secondary to deficient trophoblast invasion of the endometrial arteries, is a possible mechanism. In this review, we present evidence to show that there is a plausible basis from which to assume that blood flow in the intervillous space will be intermittent in all normal pregnancies. The intermittency will be exacerbated by impaired conversion of the spiral arteries, or by the presence of atherotic changes that reduce their caliber as seen in preeclampsia. Placental oxidative stress can be the consequences of fluctuations in oxygen concentrations after H/R through the actions of reactive oxygen species. On this basis, there will be a complete spectrum of placental changes among the normal, the late onset and the early onset preeclamptic states. Viewing the syndrome as a continuum of H/R insults provides new insight into the pathophysiology of pregnancy that will hope fully lead to improved clinical interventions.

Apport de l'imagerie neurologique chez les éclamptiques encore symptomatiques après 24 heures : étude descriptive à propos de 19 cas

OBJECTIVE

To describe the neuroimaging findings in eclamptic patients still symptomatic after 24 hours.

PATIENTS AND METHODS

All parturients consecutively admitted over a 12-month period for eclampsia and presenting with neurological disorders (coma, focal neurological abnormalities, and eye sight disturbance) underwent cerebral CT-scan and/or MRI.

RESULTS

Nineteen women were studied, and all had abnormal neuroradiological findings. The CT-scan was normal in three cases. Cerebral oedema was the predominant lesion (14 cases). It was localized in the parietal or occipital area (12 cases), paraventricular area (1 case), or was diffuse (1 case). Diffusion weighted MRI was performed in four cases and showed cytotoxic cerebral oedema in one case. There were three cases of cerebral venous thrombosis and two cases of intracerebral haemorrhage.

CONCLUSION

Various neuroradiological lesions can be observed in eclamptic patients. A localized cerebral oedema is the most frequent. Diffusion weighted MRI should be systematically done when neurological disorders persist.

Preeclampsia as a cause of preterm and late preterm (near-term) births

Gestational hypertension-preeclampsia is the most common medical disorder of pregnancy. It is also a major cause of maternal and perinatal morbidities. The majority of adverse pregnancy outcomes occur in patients who develop severe hypertension or severe preeclampsia, and in those who develop the clinical manifestations before 34 weeks' gestation. There is some concern regarding neonatal morbidity in the late preterm (near term) infant (34 0/7 through 36 6/7 weeks' gestation) as a result of gestational hypertension and preeclampsia. A review of the available data suggests that most deliveries of the late preterm infant in such women are justified because of the concerns about maternal and fetal safety with continued gestation. In addition, the rate of preterm delivery at 34 to 36 weeks' gestation in women with gestational hypertension or preeclampsia is low. Indeed, most admissions to Neonatal Intensive Care Unit in such pregnancies occur in those at > or =37 weeks' gestation. There is urgent need for research to assess the reasons behind preterm delivery at 34 to 36 weeks' gestation in women with hypertension and preeclampsia. In addition, there is need for research to assess the reasons for admission to the NICU in term infants born of mothers with varying severities of hypertension and preeclampsia. In this paper, the phrase "late-preterm" has been used instead of "near term," as the former was considered more appropriate to reflect this subgroup of preterm infants in a workshop on this topic held in July 2005, organized by the National Institute of Child Health and Human Development.

A novel approach to first-trimester screening for early pre-eclampsia combining serum PP-13 and Doppler ultrasound

OBJECTIVE

To investigate the value of maternal serum placental protein 13 (PP-13) measurement and uterine artery Doppler during first-trimester screening in the prediction of early pre-eclampsia.

METHODS

This was a nested case-control prospective study of pregnancies at 11 + 0 to 13 + 6 weeks of gestation. The pulsatility index (PI) of blood flow in the uterine arteries and the maternal serum concentration of PP-13 were measured in 10 women who went on to develop pre-eclampsia that necessitated delivery before 34 weeks, and in 423 unaffected women. Results were expressed as multiples of the gestation-specific median in controls (MoM). A logistic regression model was used to predict detection and false-positive rates.

RESULTS

In the cases that developed pre-eclampsia requiring delivery before 34 weeks, compared with the unaffected pregnancies, the median uterine artery PI was higher (1.43 MoM) and the median serum PP-13 level was lower (0.07 MoM; P < 0.001, Wilcoxon rank sum test for both). Modeling predicted that for a 90% detection rate of pre-eclampsia requiring delivery before 34 weeks, the false-positive rate of screening by PP-13 was 12%, by uterine artery PI was 31% and by a combination of the two methods was 9%. A policy of contingency screening, whereby all women are screened by maternal serum PP-13 and only the 14% at highest risk are then screened by Doppler, achieved a detection rate of 90% with an overall false-positive rate of 6%.

CONCLUSION

Effective screening for pre-eclampsia requiring delivery before 34 weeks can potentially be provided by assessment of a combination of maternal serum PP-13 and uterine artery Doppler in the first trimester of pregnancy.

Pathophysiology and Medical Management of Systemic Hypertension in Pregnancy

Hypertension in pregnancy includes a group of distinct disorders that require special consideration in both prevention and pharmacologic treatment. In recent years, there have been few advances regarding the pathophysiology and prevention of preeclampsia or in the recommendations for first-line drug therapy for its hypertensive complications. Similarly, the recommendations for pharmacologic treatment of women with chronic hypertension antedating pregnancy have changed little primarily because first-line medications have the advantage of having had more extensive research experience. Recent clinical trials have demonstrated the efficacy and safety of various second-line drugs for the hypertensive disorders of pregnancy; whether these therapies can eventually replace the standard recommended medications will require more extensive long-term investigation.

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.