The efficacy and fetal-maternal cardiovascular effects of transdermal glyceryl trinitrate in the prophylaxis of pre-eclampsia and its complications: a randomized double-blind placebo-controlled trial. Vitamin C and vitamin E in pregnant women at risk for pre-eclampsia (VIP trial): randomised placebo-controlled trial. A small randomised trial of low-dose aspirin in women at high risk of pre-eclampsia. Reducing stillbirths: interventions during labour.
Pre-eclampsia continues to be a major cause of maternal and perinatal mortality. A disorder of the nitric oxide system is implicated in the pathogenesis of this condition and preliminary studies have suggested a possible therapeutic role for nitric oxide donors in women with established pre-eclampsia. The aim of this study was to determine whether pre-eclampsia and its complications could be prevented by the long-term use of nitric oxide donors in a group of women identified to be at risk on the basis of abnormal uterine artery Doppler measurements.
                We enrolled 40 healthy normotensive women at high risk of pre-eclampsia selected on the basis of abnormal uterine artery Doppler waveforms at 24-26 weeks of gestation. Women were randomly allocated to receive transdermal glyceryl trinitrate 5 mg-patches or equivalent placebo patches in a double-blind randomized study. The primary outcome measures were pre-eclampsia, fetal growth restriction, preterm delivery or small for gestational age/fetal growth restriction rates. Patches were worn daily from recruitment for 10 weeks or until delivery.
                The primary outcomes were not significantly different in the placebo compared to the glyceryl trinitrate group. However, survival analysis of adverse events with gestation in both groups showed a significantly reduced risk of an adverse event in the glyceryl trinitrate group (p = 0.004), equating to a 73% reduction in hazard. There was no difference in maternal systolic and diastolic blood pressure, mean uterine artery resistance index and fetal umbilical and middle cerebral artery pulsatility indices between the groups.
                Low-dose prophylactic transdermal glyceryl trinitrate commenced late in the second trimester did not reduce the incidence of pre-eclampsia, preterm delivery or fetal growth restriction, but may increase the likelihood of a complication-free pregnancy. Transdermal glyceryl trinitrate (5 mg/day) did not affect maternal cardiovascular, uterine artery or fetal arterial Doppler parameters. Oxidative stress could play a part in pre-eclampsia, and there is some evidence to suggest that vitamin C and vitamin E supplements could reduce the risk of the disorder. Our aim was to investigate the potential benefit of these antioxidants in a cohort of women with a range of clinical risk factors.
                We did a randomised, placebo-controlled trial to which we enrolled 2410 women identified as at increased risk of pre-eclampsia from 25 hospitals. We assigned the women 1000 mg vitamin C and 400 IU vitamin E (RRR alpha tocopherol; n=1199) or matched placebo (n=1205) daily from the second trimester of pregnancy until delivery. Our primary endpoint was pre-eclampsia, and our main secondary endpoints were low birthweight (<2.5 kg) and small size for gestational age (<5th customised birthweight centile). Analyses were by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN 62368611 .
                Of 2404 patients treated, we analysed 2395 (99.6%). The incidence of pre-eclampsia was similar in treatment placebo groups (15% [n=181] vs 16% [n=187], RR 0.97 [95% CI 0.80-1.17]). More low birthweight babies were born to women who took antioxidants than to controls (28% [n=387] vs 24% [n=335], 1.15 [1.02-1.30]), but small size for gestational age did not differ between groups (21% [n=294] vs 19% [n=259], 1.12 [0.96-1.31]).
                Concomitant supplementation with vitamin C and vitamin E does not prevent pre-eclampsia in women at risk, but does increase the rate of babies born with a low birthweight. As such, use of these high-dose antioxidants is not justified in pregnancy. To determine if aspirin (ASA) therapy reduces the incidence of pre-eclampsia in women at high risk of this condition.
                Randomised clinical trial. We recruited pregnant women with gestational age at randomisation <14 weeks, who satisfied the following criteria: chronic hypertension, history of severe pre-eclampsia or eclampsia or intrauterine growth retardation (IUGR) or intrauterine foetal death. Nineteen women in the no-treatment group and 16 in the ASA group were successfully followed up.
                The mean birthweight was higher in the ASA group than in the no-treatment group (2790 g (S.D. 340 g) versus 2616 g (S.D. 779 g)), but the difference was not statistically significant. We found no statistically significant differences between the groups in the proportion of infants with birthweight below 2500 g (13.3% versus 29.4%) and the number of cases with pregnancy-induced hypertension (PIH)/pre-eclampsia (31.3% versus 36.8%).
                These limited data give some support to the potential favourable effect of early treatment with ASA in pregnant women at risk of PIH and IUGR. Approximately one million stillbirths occur annually during labour; most of these stillbirths occur in low and middle-income countries and are associated with absent, inadequate, or delayed obstetric care. The low proportion of intrapartum stillbirths in high-income countries suggests that intrapartum stillbirths are largely preventable with quality intrapartum care, including prompt recognition and management of intrapartum complications. The evidence for impact of intrapartum interventions on stillbirth and perinatal mortality outcomes has not yet been systematically examined.
                We undertook a systematic review of the published literature, searching PubMed and the Cochrane Library, of trials and reviews (N = 230) that reported stillbirth or perinatal mortality outcomes for eight interventions delivered during labour. Where eligible randomised controlled trials had been published after the most recent Cochrane review on any given intervention, we incorporated these new trial findings into a new meta-analysis with the Cochrane included studies.
                We found a paucity of studies reporting statistically significant evidence of impact on perinatal mortality, especially on stillbirths. Available evidence suggests that operative delivery, especially Caesarean section, contributes to decreased stillbirth rates. Induction of labour rather than expectant management in post-term pregnancies showed strong evidence of impact, though there was not enough evidence to suggest superior safety for the fetus of any given drug or drugs for induction of labour. Planned Caesarean section for term breech presentation has been shown in a large randomised trial to reduce stillbirths, but the feasibility and consequences of implementing this intervention routinely in low-/middle-income countries add caveats to recommending its use. Magnesium sulphate for pre-eclampsia and eclampsia is effective in preventing eclamptic seizures, but studies have not demonstrated impact on perinatal mortality. There was limited evidence of impact for maternal hyperoxygenation, and concerns remain about maternal safety. Transcervical amnioinfusion for meconium staining appears promising for low/middle income-country application according to the findings of many small studies, but a large randomised trial of the intervention had no significant impact on perinatal mortality, suggesting that further studies are needed.
                Although the global appeal to prioritise access to emergency obstetric care, especially vacuum extraction and Caesarean section, rests largely on observational and population-based data, these interventions are clearly life-saving in many cases of fetal compromise. Safe, comprehensive essential and emergency obstetric care is particularly needed, and can make the greatest impact on stillbirth rates, in low-resource settings. Other advanced interventions such as amnioinfusion and hyperoxygenation may reduce perinatal mortality, but concerns about safety and effectiveness require further study before they can be routinely included in programs.
The review identified no significant differences for the primary outcomes perinatal mortality, preterm birth less than 34 weeks' gestation, and childhood neurodevelopmental handicap, although the number of studies and participants was small. While treatment with heparin appears promising with a reduction in pre-eclampsia, eclampsia, and infant birthweight less than the 10th centile for gestational age, the number of studies and participants included was small, and to date important information about serious adverse infant and long-term childhood outcomes is unavailable. Further research is required.
[Note: The 14 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]