Interventions for preventing pre-eclampsia and its consequences: generic protocol

Alternative magnesium sulphate regimens for women with pre-eclampsia and eclampsia

BACKGROUND

Magnesium sulphate is the drug of choice for the prevention and treatment of women with eclampsia. Regimens for administration of this drug have evolved over the years, but there is no clarity on the comparative benefits or harm of alternative regimens. This is an update of a review first published in 2010.

OBJECTIVES

To assess if one magnesium sulphate regimen is better than another when used for the care of women with pre-eclampsia or eclampsia, or both, to reduce the risk of severe morbidity and mortality for the woman and her baby.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (29 April 2022), and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised trials and cluster-randomised trials comparing different regimens for administration of magnesium sulphate used in women with pre-eclampsia or eclampsia, or both. Comparisons included different dose regimens, intramuscular versus intravenous route for maintenance therapy, and different durations of therapy. We excluded studies with quasi-random or cross-over designs. We included abstracts of conference proceedings if compliant with the trustworthiness assessment.

DATA COLLECTION AND ANALYSIS

For this update, two review authors assessed trials for inclusion, performed risk of bias assessment, and extracted data. We checked data for accuracy. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

For this update, a total of 16 trials (3020 women) met our inclusion criteria: four trials (409 women) compared regimens for women with eclampsia, and 12 trials (2611 women) compared regimens for women with pre-eclampsia. Most of the included trials had small sample sizes and were conducted in low- and middle-income countries. Eleven trials reported adequate randomisation and allocation concealment. Blinding of participants and clinicians was not possible in most trials. The included studies were for the most part at low risk of attrition and reporting bias. Treatment of women with eclampsia (four comparisons) One trial compared a loading dose-alone regimen with a loading dose plus maintenance dose regimen (80 women). It is uncertain whether either regimen has an effect on the risk of recurrence of convulsions or maternal death (very low-certainty evidence). One trial compared a lower-dose regimen with standard-dose regimen over 24 hours (72 women). It is uncertain whether either regimen has an effect on the risk of recurrence of convulsion, severe morbidity, perinatal death, or maternal death (very low-certainty evidence). One trial (137 women) compared intravenous (IV) versus standard intramuscular (IM) maintenance regimen. It is uncertain whether either route has an effect on recurrence of convulsions, death of the baby before discharge (stillbirth and neonatal death), or maternal death (very low-certainty evidence). One trial (120 women) compared a short maintenance regimen with a standard (24 hours after birth) maintenance regimen. It is uncertain whether the duration of the maintenance regimen has an effect on recurrence of convulsions, severe morbidity, or side effects such as nausea and respiratory failure. A short maintenance regimen may reduce the risk of flushing when compared to a standard 24 hours maintenance regimen (risk ratio (RR) 0.27, 95% confidence interval (CI) 0.08 to 0.93; 1 trial, 120 women; low-certainty evidence). Many of our prespecified critical outcomes were not reported in the included trials. Prevention of eclampsia for women with pre-eclampsia (five comparisons) Two trials (462 women) compared loading dose alone with loading dose plus maintenance therapy. Low-certainty evidence suggests an uncertain effect with either regimen on the risk of eclampsia (RR 2.00, 95% CI 0.61 to 6.54; 2 trials, 462 women) or perinatal death (RR 0.50, 95% CI 0.19 to 1.36; 2 trials, 462 women). One small trial (17 women) compared an IV versus IM maintenance regimen for 24 hours. It is uncertain whether IV or IM maintenance regimen has an effect on eclampsia or stillbirth (very low-certainty evidence). Four trials (1713 women) compared short postpartum maintenance regimens with continuing for 24 hours after birth. Low-certainty evidence suggests there may be a wide range of benefit or harm between groups regarding eclampsia (RR 1.99, 95% CI 0.18 to 21.87; 4 trials, 1713 women). Low-certainty evidence suggests there may be little or no effect on severe morbidity (RR 0.96, 95% CI 0.71 to 1.29; 2 trials, 1233 women) or side effects such as respiratory depression (RR 0.80, 95% CI 0.25 to 2.61; 2 trials, 1424 women). Three trials (185 women) compared a higher-dose maintenance regimen versus a lower-dose maintenance regimen. It is uncertain whether either regimen has an effect on eclampsia (very low-certainty evidence). Low-certainty evidence suggests that a higher-dose maintenance regimen has little or no effect on side effects when compared to a lower-dose regimen (RR 0.79, 95% CI 0.61 to 1.01; 1 trial 62 women). One trial (200 women) compared a maintenance regimen by continuous infusion versus a serial IV bolus regimen. It is uncertain whether the duration of the maintenance regimen has an effect on eclampsia, side effects, perinatal death, maternal death, or other neonatal morbidity (very low-certainty evidence). Many of our prespecified critical outcomes were not reported in the included trials.

AUTHORS' CONCLUSIONS

Despite the number of trials evaluating various magnesium sulphate regimens for eclampsia prophylaxis and treatment, there is still no compelling evidence that one particular regimen is more effective than another. Well-designed randomised controlled trials are needed to answer this question.

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.

Antihypertensive drug therapy for mild to moderate hypertension during pregnancy

BACKGROUND

Antihypertensive drugs are often used in the belief that lowering blood pressure will prevent progression to more severe disease, and thereby improve pregnancy outcome. This Cochrane Review is an updated review, first published in 2001 and subsequently updated in 2007 and 2014.

OBJECTIVES

To assess the effects of antihypertensive drug treatments for women with mild to moderate hypertension during pregnancy.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (13 September 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised trials evaluating any antihypertensive drug treatment for mild to moderate hypertension during pregnancy, defined as systolic blood pressure 140 to 169 mmHg and/or diastolic blood pressure 90 to 109 mmHg. Comparisons were of one or more antihypertensive drug(s) with placebo, with no antihypertensive drug, or with another antihypertensive drug, and where treatment was planned to continue for at least seven days.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

For this update, we included 63 trials (data from 58 trials, 5909 women), with moderate to high risk of bias overall.We carried out GRADE assessments for the main 'antihypertensive drug versus placebo/no antihypertensive drug' comparison only. Evidence was graded from very low to moderate certainty, with downgrading mainly due to design limitations and imprecision.For many outcomes, trials contributing data evaluated different hypertensive drugs; while we did not downgrade for this indirectness, results should be interpreted with caution.Antihypertensive drug versus placebo/no antihypertensive drug (31 trials, 3485 women)Primary outcomes: moderate-certainty evidence suggests that use of antihypertensive drug(s) probably halves the risk of developing severe hypertension (risk ratio (RR) 0.49; 95% confidence interval (CI) 0.40 to 0.60; 20 trials, 2558 women), but may have little or no effect on the risk of proteinuria/pre-eclampsia (average risk ratio (aRR) 0.92; 95% CI 0.75 to 1.14; 23 trials, 2851 women; low-certainty evidence). Moderate-certainty evidence also shows that antihypertensive drug(s) probably have little or no effect in the risk of total reported fetal or neonatal death (including miscarriage) (aRR 0.72; 95% CI 0.50 to 1.04; 29 trials, 3365 women), small-for-gestational-age babies (aRR 0.96; 95% CI 0.78 to 1.18; 21 trials, 2686 babies) or preterm birth less than 37 weeks (aRR 0.96; 95% CI 0.83 to 1.12; 15 trials, 2141 women).

SECONDARY OUTCOMES

we are uncertain of the effect of antihypertensive drug(s) on the risk of maternal death, severe pre-eclampsia, or eclampsia, orimpaired long-term growth and development of the baby in infancy and childhood, because the certainty of this evidence is very low. There may be little or no effect on the risk of changed/stopped drugs due to maternal side-effects, or admission to neonatal or intensive care nursery (low-certainty evidence). There is probably little or no difference in the risk of elective delivery (moderate-certainty evidence).Antihypertensive drug versus another antihypertensive drug (29 trials, 2774 women)Primary outcomes: beta blockers and calcium channel blockers together in the meta-analysis appear to be more effective than methyldopa in avoiding an episode of severe hypertension (RR 0.70; 95% CI 0.56 to 0.88; 11 trials, 638 women). There was also an increase in this risk when other antihypertensive drugs were compared with calcium channel blockers (RR 1.86; 95% CI 1.09 to 3.15; 5 trials, 223 women), but no evidence of a difference when methyldopa and calcium channel blockers together were compared with beta blockers (RR1.18, 95% CI 0.95 to 1.48; 10 trials, 692 women). No evidence of a difference in the risk of proteinuria/pre-eclampsia was found when alternative drugs were compared with methyldopa (aRR 0.78; 95% CI 0.58 to 1.06; 11 trials, 997 women), with calcium channel blockers (aRR: 1.24, 95% CI 0.70 to 2.19; 5 trials, 375 women), or with beta blockers (aRR 1.21, 95% CI 0.88 to 1.67; 12 trials, 1107 women).For the babies, we found no evidence of a difference in the risk oftotal reported fetal or neonatal death (including miscarriage) when comparing other antihypertensive drugs with methyldopa (aRR 0.77, 95% CI 0.52 to 1.14; 22 trials, 1791 babies), with calcium channel blockers (aRR 0.90, 95% CI 0.52 to 1.57; nine trials, 700 babies), or with beta blockers (aRR: 1.23, 95% CI 0.81 to 1.88; 19 trials, 1652 babies); nor in the risk for small-for-gestational age in the comparison with methyldopa (aRR 0.79, 95% CI 0.52 to 1.20; seven trials, 597 babies), with calcium channel blockers (aRR 1.05, 95% CI 0.64 to 1.73; four trials, 200 babies), or with beta blockers (average RR 1.13, 95% CI 0.80 to 1.60; 7 trials, 680 babies). No evidence of an overall difference among groups in the risk of preterm birth (less than 37 weeks) was found in the comparison with methyldopa (aRR: 0.91; 95% CI 0.68 to 1.22; 11 trials, 835 women), with calcium channel blockers (aRR 0.85, 95% CI 0.59 to 1.23; six trials, 330 women), or with beta blockers (aRR 1.22, 95% CI 0.90 to 1.66; 9 trials, 806 women).

SECONDARY OUTCOMES

There were no cases of maternal death andeclampsia. There is no evidence of a difference in the risk of severe pre-eclampsia, changed/stopped drug due to maternal side-effects, elective delivery, admission to neonatal or intensive care nursery when other antihypertensive drugs are compared with methyldopa, calcium channel blockers or beta blockers. Impaired long-term growth and development in infancy and childhood was not reported for these comparisons.

AUTHORS' CONCLUSIONS

Antihypertensive drug therapy for mild to moderate hypertension during pregnancy reduces the risk of severe hypertension. The effect on other clinically important outcomes remains unclear. If antihypertensive drugs are used, beta blockers and calcium channel blockers appear to be more effective than the alternatives for preventing severe hypertension. High-quality large sample-sized randomised controlled trials are required in order to provide reliable estimates of the benefits and adverse effects of antihypertensive treatment for mild to moderate hypertension for both mother and baby, as well as costs to the health services, women and their families.

Planned early delivery versus expectant management for hypertensive disorders from 34 weeks gestation to term

BACKGROUND

Hypertensive disorders in pregnancy are significant contributors to maternal and perinatal morbidity and mortality. These disorders include well-controlled chronic hypertension, gestational hypertension (pregnancy-induced hypertension) and mild pre-eclampsia. The definitive treatment for these disorders is planned early delivery and the alternative is to manage the pregnancy expectantly if severe uncontrolled hypertension is not present, with close maternal and fetal monitoring. There are benefits and risks associated with both, so it is important to establish the safest option.

OBJECTIVES

To assess the benefits and risks of a policy of planned early delivery versus a policy of expectant management in pregnant women with hypertensive disorders, at or near term (from 34 weeks onwards).

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth Trials Register (12 January 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of a policy of planned early delivery (by induction of labour or by caesarean section) compared with a policy of delayed delivery ("expectant management") for women with hypertensive disorders from 34 weeks' gestation. Cluster-randomised trials would have been eligible for inclusion in this review, but we found none.Studies using a quasi-randomised design are not eligible for inclusion in this review. Similarly, studies using a cross-over design are not eligible for inclusion, because they are not a suitable study design for investigating hypertensive disorders in pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and risks of bias. Two review authors independently extracted data. Data were checked for accuracy.

MAIN RESULTS

We included five studies (involving 1819 women) in this review.There was a lower risk of composite maternal mortality and severe morbidity for women randomised to receive planned early delivery (risk ratio (RR) 0.69, 95% confidence interval (CI) 0.57 to 0.83, two studies, 1459 women (evidence graded high)). There were no clear differences between subgroups based on our subgroup analysis by gestational age, gestational week or condition. Planned early delivery was associated with lower risk of HELLP syndrome (RR 0.40, 95% CI 0.17 to 0.93, 1628 women; three studies) and severe renal impairment (RR 0.36, 95% CI 0.14 to 0.92, 100 women, one study).There was not enough information to draw any conclusions about the effects on composite infant mortality and severe morbidity. We observed a high level of heterogeneity between the two studies in this analysis (two studies, 1459 infants, I2 = 87%, Tau2 = 0.98), so we did not pool data in meta-analysis. There were no clear differences between subgroups based on our subgroup analysis by gestational age, gestational week or condition. Planned early delivery was associated with higher levels of respiratory distress syndrome (RR 2.24, 95% CI 1.20 to 4.18, three studies, 1511 infants), and NICU admission (RR 1.65, 95% CI 1.13 to 2.40, four studies, 1585 infants).There was no clear difference between groups for caesarean section (RR 0.91, 95% CI 0.78 to 1.07, 1728 women, four studies, evidence graded moderate), or in the duration of hospital stay for the mother after delivery of the baby (mean difference (MD) -0.16 days, 95% CI -0.46 to 0.15, two studies, 925 women, evidence graded moderate) or for the baby (MD -0.20 days, 95% CI -0.57 to 0.17, one study, 756 infants, evidence graded moderate).Two fairly large, well-designed trials with overall low risk of bias contributed the majority of the evidence. Other studies were at low or unclear risk of bias. No studies attempted to blind participants or clinicians to group allocation, potentially introducing bias as women and staff would have been aware of the intervention and this may have affected aspects of care and decision-making.The level of evidence was graded high (composite maternal mortality and morbidity), moderate (caesarean section, duration of hospital stay after delivery for mother, and duration of hospital stay after delivery for baby) or low (composite infant mortality and morbidity). Where the evidence was downgraded, it was mostly because the confidence intervals were wide, crossing both the line of no effect and appreciable benefit or harm.

AUTHORS' CONCLUSIONS

For women suffering from hypertensive disorders of pregnancy after 34 weeks, planned early delivery is associated with less composite maternal morbidity and mortality. There is no clear difference in the composite outcome of infant mortality and severe morbidity; however, this is based on limited data (from two trials) assessing all hypertensive disorders as one group.Further studies are needed to look at the different types of hypertensive diseases and the optimal timing of delivery for these conditions. These studies should also include infant and maternal morbidity and mortality outcomes, caesarean section, duration of hospital stay after delivery for mother and duration of hospital stay after delivery for baby.An individual patient meta-analysis on the data currently available would provide further information on the outcomes of the different types of hypertensive disease encountered in pregnancy.

Antihypertensive drug therapy for mild to moderate hypertension during pregnancy

BACKGROUND

Mild to moderate hypertension during pregnancy is common. Antihypertensive drugs are often used in the belief that lowering blood pressure will prevent progression to more severe disease, and thereby improve the outcome.

OBJECTIVES

To assess the effects of antihypertensive drug treatments for women with mild to moderate hypertension during pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2013) and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised trials evaluating any antihypertensive drug treatment for mild to moderate hypertension during pregnancy defined, whenever possible, as systolic blood pressure 140 to 169 mmHg and diastolic blood pressure 90 to 109 mmHg. Comparisons were of one or more antihypertensive drug(s) with placebo, with no antihypertensive drug, or with another antihypertensive drug, and where treatment was planned to continue for at least seven days.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data.

MAIN RESULTS

Forty-nine trials (4723 women) were included. Twenty-nine trials compared an antihypertensive drug with placebo/no antihypertensive drug (3350 women). There is a halving in the risk of developing severe hypertension associated with the use of antihypertensive drug(s) (20 trials, 2558 women; risk ratio (RR) 0.49; 95% confidence interval (CI) 0.40 to 0.60; risk difference (RD) -0.10 (-0.13 to -0.07); number needed to treat to harm (NNTH) 10 (8 to 13)) but little evidence of a difference in the risk of pre-eclampsia (23 trials, 2851 women; RR 0.93; 95% CI 0.80 to 1.08). Similarly, there is no clear effect on the risk of the baby dying (27 trials, 3230 women; RR 0.71; 95% CI 0.49 to 1.02), preterm birth (15 trials, 2141 women; RR 0.96; 95% CI 0.85 to 1.10), or small-for-gestational-age babies (20 trials, 2586 women; RR 0.97; 95% CI 0.80 to 1.17). There were no clear differences in any other outcomes.Twenty-two trials (1723 women) compared one antihypertensive drug with another. Alternative drugs seem better than methyldopa for reducing the risk of severe hypertension (11 trials, 638 women; RR (random-effects) 0.54; 95% CI 0.30 to 0.95; RD -0.11 (-0.20 to -0.02); NNTH 7 (5 to 69)). There is also a reduction in the overall risk of developing proteinuria/pre-eclampsia when beta blockers and calcium channel blockers considered together are compared with methyldopa (11 trials, 997 women; RR 0.73; 95% CI 0.54 to 0.99). However, the effect on both severe hypertension and proteinuria is not seen in the individual drugs. Other outcomes were only reported by a small proportion of studies, and there were no clear differences.

AUTHORS' CONCLUSIONS

It remains unclear whether antihypertensive drug therapy for mild to moderate hypertension during pregnancy is worthwhile.

Prevention of preeclampsia

Preeclampsia (PE) affects around 2-5% of pregnant women. It is a major cause of maternal and perinatal morbidity and mortality. In an attempt to prevent preeclampsia, many strategies based on antenatal care, change in lifestyle, nutritional supplementation, and drugs have been studied. The aim of this paper is to review recent evidence about primary and secondary prevention of preeclampsia.

Pulmonary artery flow catheters for directing management in pre-eclampsia

BACKGROUND

Gestational hypertension and pre-eclampsia can cause fluid shifts. Pulmonary oedema and renal failure can result from these shifts. Fluid management is crucial in managing pre-eclampsia, especially in the context of pulmonary oedema and renal failure. Pulmonary artery catheterisation may be a method of effectively monitoring fluid status and thus aid in the management of renal failure and pulmonary oedema in the context of pre-eclampsia.

OBJECTIVES

To assess the safety and efficacy of pulmonary flow catheters in women with severe pre-eclampsia in preventing and managing of renal failure and pulmonary oedema or both.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2012).

SELECTION CRITERIA

Randomised trials evaluating the use of the pulmonary artery catheterisation in the management of pre-eclamptic and eclamptic antepartum, intrapartum and postpartum women.

DATA COLLECTION AND ANALYSIS

We did not identify any randomised controlled studies.

MAIN RESULTS

There are no included studies.

AUTHORS' CONCLUSIONS

There is currently no evidence from randomised controlled trials supporting the use of the pulmonary artery catheters. Fluid management in pre-eclampsia, especially in the context of preventing or managing renal failure and pulmonary oedema, remains an important issue. Randomised trials dealing with this intervention are needed, however, we do recognise the difficulty in performing randomised trials due to the invasive nature of the procedure and skills involved in inserting a pulmonary flow catheter.

Magnesium sulphate versus diazepam for eclampsia

BACKGROUND

Eclampsia, the occurrence of a seizure in association with pre-eclampsia, remains a rare but serious complication of pregnancy. A number of different anticonvulsants are used to control eclamptic fits and to prevent further fits.

OBJECTIVES

The objective of this review was to assess the effects of magnesium sulphate compared with diazepam when used for the care of women with eclampsia. Magnesium sulphate is compared with phenytoin and with lytic cocktail in other Cochrane reviews.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2010) and CENTRAL (2010, Issue 3).

SELECTION CRITERIA

Randomised trials comparing magnesium sulphate (intravenous or intramuscular administration) with diazepam for women with a clinical diagnosis of eclampsia.

DATA COLLECTION AND ANALYSIS

Two authors assessed and extracted data independently.

MAIN RESULTS

We have included seven trials, involving 1396 women. Three trials (1030 women) were good quality. Magnesium sulphate was associated with a reduction in maternal death (seven trials;1396 women; risk ratio (RR) 0.59, 95% confidence interval (CI) 0.38 to 0.92) and recurrence of seizures (seven trials;1390 women; RR 0.43, 95% CI 0.33 to 0.55) compared to diazepam. There were no clear differences in other measures of maternal morbidity.There was no clear difference in perinatal mortality (four trials; 788 infants; RR 1.04, 95% CI 0.81 to 1.34) or neonatal mortality (four trials; 759 infants; RR 1.18, 95% CI 0.75 to 1.84). In the magnesium sulphate group, fewer liveborn babies had an Apgar score less than seven at one minute (two trials; 597 babies; RR 0.75, 95% CI 0.65 to 0.87) or at five minutes (RR 0.70, 95% CI 0.54 to 0.90), and fewer appeared to need intubation at the place of birth (two trials; 591 infants; RR 0.67, 95% CI 0.45 to 1.00). There was no difference in admission to a special care nursery (four trials; 834 infants; RR 0.91, 95% CI 0.79 to 1.05), but fewer babies in the magnesium sulphate group had a length of stay more than seven days (three trials 631 babies; RR 0.66, 95% CI 0.46 to 0.96).

AUTHORS' CONCLUSIONS

Magnesium sulphate for women with eclampsia reduces the risk ratio of maternal death and of recurrence of seizures, compared with diazepam.

Magnesium sulphate versus phenytoin for eclampsia

BACKGROUND

Eclampsia, the occurrence of a seizure in association with pre-eclampsia, remains a rare but serious complication of pregnancy. A number of different anticonvulsants have been used to control eclamptic fits and to prevent further seizures.

OBJECTIVES

The objective of this review was to assess the effects of magnesium sulphate compared with phenytoin when used for the care of women with eclampsia. Magnesium sulphate is compared with diazepam and with lytic cocktail in other Cochrane reviews.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2010).

SELECTION CRITERIA

Randomised trials comparing magnesium sulphate (intravenous or intramuscular administration) with phenytoin for women with a clinical diagnosis of eclampsia.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial quality and extracted data.

MAIN RESULTS

We have included data from seven trials, involving 972 women. One large trial (775 women) was of good quality. Magnesium sulphate was associated with a substantial reduction in the recurrence of seizures, when compared to phenytoin (six trials, 972 women; risk ratio (RR) 0.34, 95% confidence interval (CI) 0.24 to 0.49). The trend in maternal mortality favours magnesium sulphate, but the difference does not reach statistical significance (three trials, 847 women; RR 0.50, 95% CI 0.24 to 1.05). There were reductions in the risk of pneumonia (one trial, RR 0.44, 95% CI 0.24 to 0.79), ventilation (one trial, RR 0.68, 95% CI 0.50 to 0.91) and admission to an intensive care unit (one trial, RR 0.67, 95% CI 0.50 to 0.89) associated with the use of magnesium sulphate rather than phenytoin.For the baby, magnesium sulphate was associated with fewer admissions to a special care baby unit (SCBU) (one trial, 518 babies; RR 0.73, 95% CI 0.58 to 0.91) and fewer babies who died or were in SCBU for more than seven days (one trial, 643 babies; RR 0.77, 95% CI 0.63 to 0.95) than phenytoin. There was no clear difference in perinatal deaths (two trials, 665 babies; (RR 0.85, 95% CI 0.67 to 1.09).

AUTHORS' CONCLUSIONS

Magnesium sulphate, rather than phenytoin, for women with eclampsia reduces the risk ratio of recurrence of seizures, probably reduces the risk of maternal death, and improves outcome for the baby. Magnesium sulphate is the drug of choice for women with eclampsia. The use of phenytoin should be abandoned.

Magnesium sulphate versus lytic cocktail for eclampsia

BACKGROUND

Eclampsia, the occurrence of a seizure in association with pre-eclampsia, is a rare but serious complication of pregnancy. A number of different anticonvulsants have been used to control eclamptic fits and to prevent further seizures.

OBJECTIVES

The objective of this review was to assess the effects of magnesium sulphate compared with lytic cocktail (usually chlorpromazine, promethazine and pethidine) when used for the care of women with eclampsia. Magnesium sulphate is compared with diazepam and with phenytoin in other Cochrane reviews.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2010) and the Cochrane Central Register of Trials (The Cochrane Library 2010, Issue 2).

SELECTION CRITERIA

Randomised trials comparing magnesium sulphate (intravenous or intramuscular administration) with lytic cocktail for women with a clinical diagnosis of eclampsia.

DATA COLLECTION AND ANALYSIS

Two review authors (L Duley and D Chou) assessed trial quality and extracted data.

MAIN RESULTS

We included three small trials (total 397 women) of average quality in the review. Magnesium sulphate was associated with fewer maternal deaths (risk ratio (RR) 0.14, 95% confidence interval (CI) 0.03 to 0.59; 3 trials, 397 women) and was better at preventing further seizures (RR 0.06, 95% CI 0.03 to 0.12; 3 trials, 397 women) than lytic cocktail. Magnesium sulphate was also associated with less respiratory depression (RR 0.12, 95% CI 0.02 to 0.91; 2 trials, 198 women), less coma (RR 0.04, 95% CI 0.00 to 0.74; 1 trial, 108 women), and less pneumonia (RR 0.20, 95% CI 0.06 to 0.67; 2 trials, 307 women). There was no clear difference in the RR for any death of the baby (RR 0.35, 95% CI 0.05 to 2.38, random effects; 2 trials, 177 babies).

AUTHORS' CONCLUSIONS

Magnesium sulphate, rather than lytic cocktail, for women with eclampsia reduces the RR of maternal death, of further seizures and of serious maternal morbidity (respiratory depression, coma, pneumonia). Magnesium sulphate is the anticonvulsant of choice for women with eclampsia; the use of lytic cocktail should be abandoned.

Antioxidants for preventing pre-eclampsia

BACKGROUND

Oxidative stress has been proposed as a key factor involved in the development of pre-eclampsia. Supplementing women with antioxidants during pregnancy may help to counteract oxidative stress and thereby prevent or delay the onset of pre-eclampsia.

OBJECTIVES

To determine the effectiveness and safety of any antioxidant supplementation during pregnancy and the risk of developing pre-eclampsia and its related complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2006, Issue 3), MEDLINE (1950 to October 2007) and Current Contents (1998 to August 2004).

SELECTION CRITERIA

All randomised trials comparing one or more antioxidants with either placebo or no antioxidants during pregnancy for the prevention of pre-eclampsia, and trials comparing one or more antioxidants with another, or with other interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and trial quality and extracted data.

MAIN RESULTS

Ten trials, involving 6533 women, were included in this review, five trials were rated high quality. For the majority of trials, the antioxidant assessed was combined vitamin C and E therapy. There was no significant difference between antioxidant and control groups for the relative risk (RR) of pre-eclampsia (RR 0.73, 95% confidence intervals (CI) 0.51 to 1.06; nine trials, 5446 women) or any other primary outcome: severe pre-eclampsia (RR 1.25, 95% CI 0.89 to 1.76; two trials, 2495 women), preterm birth (before 37 weeks) (RR 1.10, 95% CI 0.99 to 1.22; five trials, 5198 women), small-for-gestational-age infants (RR 0.83, 95% CI 0.62 to 1.11; five trials, 5271 babies) or any baby death (RR 1.12, 95% CI 0.81 to 1.53; four trials, 5144 babies). Women allocated antioxidants were more likely to self-report abdominal pain late in pregnancy (RR 1.61, 95% CI 1.11 to 2.34; one trial, 1745 women), require antihypertensive therapy (RR 1.77, 95% CI 1.22 to 2.57; two trials, 4272 women) and require an antenatal hospital admission for hypertension (RR 1.54, 95% CI 1.00 to 2.39; one trial, 1877 women). However, for the latter two outcomes, this was not clearly reflected in an increase in any other hypertensive complications.

AUTHORS' CONCLUSIONS

Evidence from this review does not support routine antioxidant supplementation during pregnancy to reduce the risk of pre-eclampsia and other serious complications in pregnancy.

Nitric oxide for preventing pre-eclampsia and its complications

BACKGROUND

Pre-eclampsia, a multisystem disorder of pregnancy characterised by high blood pressure and protein in the urine, is associated with endothelial dysfunction. Nitric oxide mediates many functions of the endothelium, including vasodilatation and inhibition of platelet aggregation. Pre-eclampsia may be associated with nitric oxide deficiency, but the evidence to support this suggestion is contradictory. Nevertheless, it has been hypothesised that agents which increase nitric oxide may prevent pre-eclampsia.

OBJECTIVES

To assess the effectiveness and safety of nitric oxide donors and precursors for preventing pre-eclampsia and its complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (November 2006), CENTRAL (The Cochrane Library 2006, Issue 3), and EMBASE (2002 to December 2004).

SELECTION CRITERIA

Studies were included if they were randomised trials evaluating nitric oxide donors or precursors for preventing pre-eclampsia and its complications.

DATA COLLECTION AND ANALYSIS

Both review authors independently assessed studies for inclusion. Data were extracted and double checked for accuracy.

MAIN RESULTS

Six trials (310 women) were included. Four were of good quality and two were of uncertain quality. Four trials (170 women) compared nitric oxide donors (glyceryl trinitrate) or precursors (L-arginine) with either placebo or no intervention. There are insufficient data for reliable conclusions about the effects on pre-eclampsia (four trials, 170 women; relative risk (RR) 0.83, 95% confidence interval (CI) 0.49 to 1.41) or its complications. One trial (36 women) compared a nitric oxide donor with nifedipine, and another (76 women) compared it with antiplatelet agents. Both were too small for reliable conclusions about possible differential effects. Glyceryl trinitrate was associated with an increased risk of headache (two trials, 56 women; RR 6.85, 95% CI 1.42 to 33.04), and of stopping treatment (two trials, 56 women; RR 4.02, 95% CI 1.15 to 14.09) compared to placebo. However, the increase for both outcomes was due to an extreme result in one small trial (7/7 versus 0/9 for both outcomes).

AUTHORS' CONCLUSIONS

There is insufficient evidence to draw reliable conclusions about whether nitric oxide donors and precursors prevent pre-eclampsia or its complications.

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.

Low-dose dopamine for women with severe pre-eclampsia

BACKGROUND

Hypertensive disorders during pregnancy are important causes of maternal mortality and morbidity worldwide. The long-term outcome of surviving mothers will depend largely on whether intracranial haemorrhage or renal failure developed. Low-dose dopamine is used for the prevention and treatment of acute renal failure, but its role in the management of pregnant women with severe pre-eclampsia is unclear.

OBJECTIVES

To assess the effects of low-dose dopamine used for oliguria in severe pre-eclampsia on mothers and their children.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2006).

SELECTION CRITERIA

Randomised trials comparing low-dose dopamine (dosages not higher than 5 microgram/kg/minute) with either placebo or no dopamine in women with severe pre-eclampsia and acute renal failure, or who are considered to be at risk of acute renal failure.

DATA COLLECTION AND ANALYSIS

The two review authors assessed trial quality and data independently.

MAIN RESULTS

Only one randomised placebo controlled trial of six hours' duration, including 40 postpartum women, was found. This study showed a significant increase in urinary output over six hours in women receiving dopamine. It is unclear if this was of any benefit to the women.

AUTHORS' CONCLUSIONS

It is unclear whether low-dose dopamine therapy for pre-eclamptic women with oliguria is worthwhile. It should not be used other than in prospective trials.

Diuretics for preventing pre-eclampsia

BACKGROUND

Diuretics are used to reduce blood pressure and oedema in non-pregnant individuals. Formerly, they were used in pregnancy with the aim of preventing or delaying the development of pre-eclampsia. This practice became controversial when concerns were raised that diuretics may further reduce plasma volume in women with pre-eclampsia, thereby increasing the risk of adverse effects on the mother and baby, particularly fetal growth.

OBJECTIVES

To assess the effects of diuretics on prevention of pre-eclampsia and its complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (April 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2005, Issue 2) and EMBASE (2002 to April 2005).

SELECTION CRITERIA

Randomised trials evaluating the effects of diuretics for preventing pre-eclampsia and its complications.

DATA COLLECTION AND ANALYSIS

Three review authors independently selected trials for inclusion and extracted data. We analysed and double checked data for accuracy.

MAIN RESULTS

Five studies (1836 women) were included. All were of uncertain quality. The studies compared thiazide diuretics with either placebo or no intervention. There were no clear differences between the diuretic and control groups for any reported pregnancy outcomes including pre-eclampsia (four trials, 1391 women; relative risk (RR) 0.68, 95% confidence interval (CI) 0.45 to 1.03), perinatal death (five trials,1836 women; RR 0.72, 95% CI 0.40 to 1.27), and preterm birth (two trials, 465 women; RR 0.67, 95% CI 0.32 to 1.41). There were no small-for-gestational age babies in the one trial that reported this outcome, and there was insufficient evidence to demonstrate any clear differences between the two groups for birthweight (one trial, 20 women; weighted mean difference 139 grams, 95% CI -484.40 to 762.40). Thiazide diuretics were associated with an increased risk of nausea and vomiting (two trials, 1217 women; RR 5.81, 95% CI 1.04 to 32.46), and women allocated diuretics were more likely to stop treatment due to side-effects compared to those allocated placebo (two trials, 1217 women; RR 1.85, 95% CI 0.81 to 4.22).

AUTHORS' CONCLUSIONS

There is insufficient evidence to draw reliable conclusions about the effects of diuretics on prevention of pre-eclampsia and its complications. However, from this review, no clear benefits have been found from the use of diuretics to prevent pre-eclampsia. Taken together with the level of adverse effects found, the use of diuretics for the prevention of pre-eclampsia and its complications cannot be recommended.

Progesterone for preventing pre-eclampsia and its complications

BACKGROUND

In the past, progesterone has been advocated for prevention of pre-eclampsia and its complications. Although progestogens are not used for this purpose in current clinical practice, it remains relevant to assess the evidence on their possible benefits and harms.

OBJECTIVES

To assess the effects of progesterone during pregnancy on the risk of developing pre-eclampsia and its complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (April 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2006, Issue 2), and EMBASE (1974 to August 2005).

SELECTION CRITERIA

Randomised trials evaluating progesterone or any other progestogen during pregnancy for prevention of pre-eclampsia and its complications were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion and extracted data.

MAIN RESULTS

Two trials of uncertain quality were included (296 women). These trials compared progesterone injections with no progesterone. There was insufficient evidence to demonstrate any clear differences between the two groups on the risk of pre-eclampsia (one trial, 128 women; relative risk (RR) 0.21, 95% confidence interval (CI) 0.03 to 1.77), death of the baby (two trials, 296 women; RR 0.72, 95% CI 0.21 to 2.51), preterm birth (one trial, 168 women; RR 1.10, 95% CI 0.33 to 3.66), small-for-gestational-age babies (one trial, 168 women; RR 0.83, 95% CI 0.19 to 3.57) or major congenital defects (one trial, 168 women; RR 1.65, 95% CI 0.28 to 9.62). There were no reported cases of masculinisation of female babies (one trial, 128 women). Long-term follow up for the children has been reported in one trial, but the data are excluded from the review as 54% were lost to follow up at one year and 80% at 16 years.

AUTHORS' CONCLUSIONS

There is insufficient evidence for reliable conclusions about the effects of progesterone for preventing pre-eclampsia and its complications. Therefore, progesterone should not be used for this purpose in clinical practice at present. Unless new and plausible hypotheses emerge for the role of progesterone in development of pre-eclampsia, further trials of progesterone are unlikely to be a priority.

Exercise or other physical activity for preventing pre-eclampsia and its complications

BACKGROUND

The association between an increase in regular physical activity and a reduction in the risk of hypertension is well documented for non-pregnant people. It has been suggested that exercise may help prevent pre-eclampsia and its complications. Possible adverse effects of increased physical activity during pregnancy, particularly on the risk of preterm birth and fetal growth restriction, are unclear. It is, therefore, important to assess whether exercise reduces the risk of pre-eclampsia and its complications and, if so, whether these benefits outweigh the risks.

OBJECTIVES

To assess the effects of exercise, or increased physical activity, on prevention of pre-eclampsia and its complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (December 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2005, Issue 1), and EMBASE (2002 to February 2005).

SELECTION CRITERIA

Studies were included if these were randomised trials evaluating the effects of exercise or increased physical activity during pregnancy for women at risk of pre-eclampsia.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted data. Data were entered on Review Manager software for analysis, and double checked for accuracy.

MAIN RESULTS

Two small, good quality trials (45 women) were included. Both compared moderate intensity regular aerobic exercise with maintenance of normal physical activity during pregnancy. The confidence intervals were wide and crossed the line of no effect for all reported outcomes including pre-eclampsia (relative risk 0.31, 95% confidence interval 0.01 to 7.09).

AUTHORS' CONCLUSIONS

There is insufficient evidence for reliable conclusions about the effects of exercise on prevention of pre-eclampsia and its complications.

Chinese herbal medicine for the treatment of pre-eclampsia

BACKGROUND

Pre-eclampsia is a common disorder of pregnancy with uncertain etiology. In Chinese herbal medicines, a number of herbs are used for treating pre-eclampsia. Traditional Chinese medicine considers that, when a woman is pregnant, most of the blood of the mother is directed to the placenta to provide the baby with the required nutrition; other maternal organs may in consequence be vulnerable to damage. These organs include the liver, the spleen, and the kidneys. The general effects of Chinese herbal medicines that can protect these organs may be valuable in pre-eclampsia by encouraging vasodilatation, increasing blood flow, and decreasing platelet aggregation. The use of Chinese herbal medicine is often based on the individual and presence of traditional Chinese medicine symptoms.

OBJECTIVES

To assess the effect of Chinese herbal medicine for treating pre-eclampsia and compare it with that of placebo, no treatment or Western medicine.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Groups Trial Register (31 March 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2005), MEDLINE (1969 to December 2004), EMBASE (1984 to March 2004) and CBM (1978 to February 2005) and we handsearched several main journals published in China.

SELECTION CRITERIA

Randomized controlled trials in which Chinese herbal medicine was used for treating pre-eclampsia.

DATA COLLECTION AND ANALYSIS

One review author assessed trials for inclusion. The trials were also assessed by a second review author if there was any doubt about whether or not to include the trial. Analysis was not performed as there were no trials included in this review.

MAIN RESULTS

No trials were suitable for inclusion in this review.

AUTHORS' CONCLUSIONS

The effect of Chinese herbal medicine for treating pre-eclampsia remains unclear. There are currently no randomized controlled trials to address the efficacy and safety of Chinese herbal medicine for the treatment of pre-eclampsia. Well conducted randomized controlled trials are required.

Rest during pregnancy for preventing pre-eclampsia and its complications in women with normal blood pressure

BACKGROUND

Women at risk of pre-eclampsia or gestational hypertension are sometimes advised to rest. Whether this, overall, does more good than harm is unclear.

OBJECTIVES

To assess the effects of rest or advice to reduce physical activity during pregnancy for preventing pre-eclampsia and its complications in women with normal blood pressure.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (December 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2005), and EMBASE (2002 to August 2005).

SELECTION CRITERIA

Studies were included if they were randomised trials evaluating the effects of rest or advise to reduce physical activity for preventing pre-eclampsia and its complications in women with normal blood pressure.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted data. Data were double checked for accuracy.

MAIN RESULTS

Two small trials (106 women) of uncertain quality were included. Both recruited women with a singleton pregnancy at moderate risk of pre-eclampsia from 28 to 32 weeks' gestation. There was a statistically significant reduction in the relative risk of pre-eclampsia with four to six hours rest per day (one trial, 32 women; relative risk (RR) 0.05, 95% confidence interval (CI) 0.00 to 0.83), but not of gestational hypertension (RR 0.25, 95% CI 0.03 to 2.00), compared to normal activity. Rest of 30 minutes per day plus nutritional supplementation was associated with a reduction in the risk of pre-eclampsia (one trial, 74 women; RR 0.13, 95% CI 0.03 to 0.51) and also of gestational hypertension (RR 0.15, 95% CI 0.04 to 0.63). The effect on caesarean section was unclear (RR 0.82, 95% CI 0.48 to 1.41). No other outcomes were reported.

AUTHORS' CONCLUSIONS

Daily rest, with or without nutrient supplementation, may reduce the risk of pre-eclampsia for women with normal blood pressure, although the reported effect may reflect bias and/or random error rather than a true effect. There is no information about outcomes such as perinatal mortality and morbidity, maternal morbidity, women's views, adverse effects, and costs. Current evidence is insufficient to support recommending rest or reduced activity to women for preventing pre-eclampsia and its complications. Whether women rest during pregnancy should therefore be a matter of personal choice.

Relationship between high consumption of marine fatty acids in early pregnancy and hypertensive disorders in pregnancy

OBJECTIVE

To investigate whether there is a relationship between maternal intake of cod-liver oil in early and late pregnancy and hypertensive disorders in pregnancy.

DESIGN

An observational prospective study.

SETTING

Free-living conditions in a community with traditional fish and cod-liver oil consumption.

POPULATION

Four hundred and eighty-eight low-risk pregnant Icelandic women.

METHODS

Maternal use of cod-liver oil, foods and other supplements was estimated with a semiquantitative food frequency questionnaire covering food intake together with lifestyle factors for the previous 3 months. Questionnaires were filled out twice, between 11 and 15 weeks of gestation and between 34 and 37 weeks of gestation. Supplements related to hypertensive disorders in pregnancy, i.e. gestational hypertension and pre-eclampsia, were presented, with logistic regression controlling for potential confounding.

MAIN OUTCOME MEASURES

Gestational hypertension, pre-eclampsia, cod-liver oil and multivitamins.

RESULTS

The odds ratio for developing hypertensive disorders in pregnancy for women consuming liquid cod-liver oil was 4.7 (95% CI 1.8-12.6, P= 0.002), after adjusting for confounding factors. By dividing the amount of n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) into centiles, the odds ratio for hypertensive disorders across groups for n-3 LCPUFA suggested a u-shaped curve (P = 0.008). Similar results were found for gestational hypertension alone. Further, the use of multivitamin supplements without vitamins A and D in late pregnancy doubled the odds of hypertensive disorders (OR 2.4, 95% CI 1.0-5.4, P= 0.044).

CONCLUSIONS

Consumption of high doses of n-3 LCPUFA in early pregnancy, or other nutrients found in liquid cod-liver oil, may increase the risk of developing hypertensive disorders in pregnancy.

Bed rest with or without hospitalisation for hypertension during pregnancy

BACKGROUND

Bed rest or restriction of activity, with or without hospitalisation, have been advocated for women with hypertension during pregnancy to improve pregnancy outcome. However, benefits need to be demonstrated before such interventions can be recommended since restricted activity may be disruptive to women's lives, expensive, and increase the risk of thromboembolism.

OBJECTIVES

To assess the effects on the mother and the baby of different degrees of bed rest, compared with each other, and with routine activity, in hospital or at home, for primary treatment of hypertension during pregnancy.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (April 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2005), and EMBASE (January 2002 to December 2004).

SELECTION CRITERIA

Randomised trials evaluating bed rest for women with hypertension in pregnancy were selected.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trials for inclusion independently, and extracted data. Data were entered into RevMan software and double-checked.

MAIN RESULTS

Four small trials (449 women) were included. Three were of good quality. Two trials (145 women) compared strict bed rest with some rest, in hospital, for women with proteinuric hypertension. There was insufficient evidence to demonstrate any differences between the groups for reported outcomes. Two trials (304 women) compared some bed rest in hospital with routine activity at home for non-proteinuric hypertension. There was reduced risk of severe hypertension (1 trial, 218 women; RR 0.58, 95% CI 0.38 to 0.89) and a borderline reduction in risk of preterm birth (1 trial, 218 women; RR 0.53, CI 0.29 to 0.99) with some rest compared to normal activity. More women in the bed rest group opted not to have the same management in future pregnancies, if the choice were given (1 trial, 86 women; RR 3.00, 95% CI 1.43 to 6.31). There were no significant differences for any other outcomes.

AUTHORS' CONCLUSIONS

Few randomised trials have evaluated rest for women with hypertension during pregnancy, and important information on side-effects and cost implication is missing from available trials. Although one small trial suggests that some bed rest may be associated with reduced risk of severe hypertension and preterm birth, these findings need to be confirmed in larger trials. At present, there is insufficient evidence to provide clear guidance for clinical practice. Therefore, bed rest should not be recommended routinely for hypertension in pregnancy, especially since more women appear to prefer unrestricted activity, if the choice were given.