Prophylaxis for venous thromboembolic disease in pregnancy and the early postnatal period

BACKGROUND

Venous thromboembolic disease (TED), although very rare, is a major cause of maternal mortality and morbidity, hence methods of prophylaxis are often used for women at risk. This may include women delivered by caesarean section, those with a personal or family history of TED and women with inherited or acquired thrombophilias (conditions that predispose people to thrombosis). Many methods of prophylaxis carry a risk of side effects, and as the risk of thromboembolic disease is low, it is possible that the benefits of thromboprophylaxis may be outweighed by harm. Current guidelines for clinical practice are based on expert opinion only, rather than high quality evidence from randomised trials.

OBJECTIVES

To determine the effects of thromboprophylaxis in association with pregnancy in women who are pregnant or have recently delivered on the incidence of venous thromboembolic disease and side effects.

SEARCH STRATEGY

The register of trials maintained by the Cochrane Pregnancy and Childbirth Group, the Cochrane Controlled Trials Register, MEDLINE, EMBASE and bibliographies of reviews. Date of last search: January 2002.

SELECTION CRITERIA

Randomised trials comparing one method of thromboprophylaxis with placebo or no treatment, and randomised trials comparing two (or more) methods of thromboprophylaxis.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by all reviewers. Discrepancies were resolved by discussion.

MAIN RESULTS

Eight trials involving 649 women were included. Four of them compared methods of antenatal prophylaxis; low molecular weight versus unfractionated heparin (two studies), aspirin plus heparin versus aspirin alone (one study), and unfractionated heparin versus no treatment (one study). Four studies assessed postnatal prophylaxis after caesarean section; one compared hydroxyethyl starch with unfractionated heparin, two compared heparin with placebo (one low molecular weight heparin, one unfractionated heparin) and the other compared unfractionated heparin with low molecular weight heparin. It was not possible to assess the effects of any of these interventions on most outcomes, especially rare outcomes such as death, thromboembolic disease and osteoporosis, because of small sample sizes and the small number of trials making the same comparisons.

REVIEWER'S CONCLUSIONS

There is insufficient evidence on which to base recommendations for thromboprophylaxis during pregnancy and the early postnatal period. Large scale randomised trials of currently-used interventions should be conducted.

Antiretrovirals for reducing the risk of mother-to-child transmission of HIV infection

BACKGROUND

At the end of 2000 it was estimated that over 36 million people were living with the human immunodeficiency virus (HIV). This includes 1.4 million children less than 15 years of age. This is one of several reviews assessing the available evidence for preventing mother-to-child transmission of HIV infection. The other reviews will address other interventions, including Caesarean section, breast feeding, vaginal lavage and vitamin A supplementation.

OBJECTIVES

To assess which antiretroviral therapies may be effective in decreasing the risk of mother-to-child transmission of HIV infection as well as their effect on neonatal and maternal mortality and morbidity.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register. We also searched conference abstracts from the International AIDS Conferences and Conference on Retroviruses and Opportunistic Infections.

SELECTION CRITERIA

Randomised trials comparing any antiretroviral therapy aimed at decreasing the risk of mother-to-child transmission of HIV infection with placebo or no treatment, or any two or more antiretroviral therapies or regimens aimed at decreasing the risk of mother-to-child transmission of HIV infection.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality.

MAIN RESULTS

Zidovudine monotherapy Any zidovudine regimen versus placebo significantly reduces the risk of mother-to-child transmission (Peto odds ratio (OR) 0.46, 95% confidence interval (CI) 0.35 to 0.60). Zidovudine also appears to decrease the risk of infant death within the first year of birth (OR 0.57, 95% CI 0.38 to 0.85) and the risk of maternal death (OR 0.32, 95% CI 0.16 to 0.66). There is no evidence that zidovudine influences the incidence of premature delivery (OR 0.86, 95% CI 0.57 to 1.29) or low birth weight (OR 0.74, 95% CI 0.53 to 1.04). The risk of transmission using a 'short-short' course of zidovudine (from 35 weeks in pregnancy for the mother and for the baby until 3 days old) was higher than the risk using a 'long-long' course (from 28 weeks in pregnancy for the mother and for the baby until 6 weeks old), (OR 2.55, 95% CI 1.26 to 5.18). However, the effectiveness of the 'long-short' course (from 28 weeks in pregnancy for the mother and for the baby until 3 days old) and the 'short-long' course (from 35 weeks in pregnancy for the mother and for the baby until 6 weeks old) did not differ from that of the 'long-long' course. Nevirapine One large randomised controlled trial demonstrates that nevirapine given to mothers as a single dose at the onset of labour and to babies as a single dose within 72 hours of birth is more effective than an intrapartum and post-partum regimen of zidovudine (OR 0.51, 95% CI 0.33 to 0.79). When nevirapine is given to mothers already receiving standard antiretroviral therapy, however, there appears to be no additional advantage (OR 1.10, 95% CI 0.42 to 2.86). Combination Therapy Preliminary findings of the effect of combination therapy using zidovudine and lamivudine (3TC) suggest a decrease in the risk of transmission when the combination is given during the antenatal and intrapartum period or during the intrapartum and postpartum period compared with placebo. There is no evidence that intrapartum zidovudine and lamivudine alone are sufficient to decrease the risk of transmission compared with placebo.

REVIEWER'S CONCLUSIONS

Implications for practice The randomised trials included in this review provide evidence that short course zidovudine and single-dose nevirapine are effective therapies for reducing mother-to-child transmission of HIV. The challenge for low and middle income countries will be to institute this therapy in practice. In industrialised countries practice has already moved on from the current evidence and combination antiretroviral therapy aimed primarily at preventing disease progression in the mother is the standard of care. Implications for research The potential value of nevirapine used for longer durations in breastfeeding populations should be considered as it may further reduce the risk of mother-to-child transmission, particularly if combined with early weaning. On-going evaluation of combination antiretroviral therapy is essential and will have an immediate benefit for countries with the resources to adopt such treatment. The search for effective, affordable, safe and acceptable alternatives to antiretroviral therapy for reducing mother-to-child transmission in resource poor countries should remain on the research agenda.

Vitamin A supplementation for reducing the risk of mother-to-child transmission of HIV infection

BACKGROUND

Mother-to-child transmission (MTCT) of HIV is the dominant mode of acquisition of HIV infection for children, currently resulting in about 1800 new paediatric HIV infections each day world-wide. This is one of several reviews assessing the available evidence for preventing HIV transmission from an HIV-infected woman to her child. The other reviews assess the effects of antiretroviral therapy, Caesarean section delivery, breast feeding, and vaginal lavage.

OBJECTIVES

To assess the effects of antenatal and intrapartum vitamin A supplementation, compared to an appropriate control group, on the risk of MTCT of HIV infection and infant and maternal mortality and morbidity, and the tolerability of vitamin A supplementation.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register, Cochrane Pregnancy and Childbirth Register, PubMed, EMBASE, AIDSLINE, LILACS, AIDSTRIALS, and AIDSDRUGS, using standardised methodological filters for identifying trials. We also searched reference lists of identified articles, relevant editorials, expert opinions and letters to journal editors, and abstracts or proceedings of relevant conferences; and contacted subject experts, agencies, organisations, academic centres, and pharmaceutical companies. There were no language restrictions.

SELECTION CRITERIA

Randomised trials comparing vitamin A supplementation with no vitamin A supplementation in known HIV infected pregnant women. Trials had to include an estimate of the effect of vitamin A supplementation on MTCT of HIV and/or any other pre-specified adverse pregnancy outcome to be included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial eligibility and quality and extracted data. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for binary data and pooled using a fixed effect (Mantel-Haenszel) method. Heterogeneity between studies was examined by graphical inspection of results followed by a chi-square test of homogeneity.

MAIN RESULTS

We identified five eligible trials, only two of which included an estimated of the effect of vitamin A supplementation on at least one of the pre-specified outcomes. Based on the two trials, with a total of 1813 participants, there is no evidence that vitamin A supplementation has an effect on MTCT of HIV (OR 1.09, 95% confidence interval (CI) 0.81 to 1.45). There is no evidence of heterogeneity between the trials (p = 0.37), and no evidence of an effect of vitamin A supplementation in HIV-infected pregnant women on stillbirths (OR 1.07, 95% CI 0.63 to 1.80), very preterm births, i.e. born less than 34 weeks gestation (OR 0.86, 95% CI 0.57 to 1.31), all preterm births, i.e. born less than 37 weeks gestation (OR 0.88, 95% CI 0.68 to 1.13), low birth weight, i.e. weighing less than 2500g (OR 0.86, 95% CI 0.64 to 1.17), very low birthweight, i.e. weighing less than 2000g (OR 0.71, 95% CI 0.40 to 1.28), and postpartum CD4 levels (weighted mean difference -4.00, 95% CI -51.06 to 43.06). The effect of vitamin A on maternal mortality could not be assesssed, as there were only three maternal deaths.

IMPLICATIONS FOR PRACTICE

At the present time there is no conclusive evidence that the antenatal and intrapartum use of vitamin A supplementation to reduce MTCT of HIV and adverse pregnancy outcomes among HIV-infected pregnant women should be recommended.

IMPLICATIONS FOR RESEARCH

The current review will be updated as soon as data from ongoing studies become available. This review and the review in progress on vitamin A supplementation in pregnant women of seronegative/unknown HIV status (Kulier 2002) should be considered together in order to shed more light on the effect of vitamin A supplementation on non-HIV related adverse pregnancy outcomes.

Vaginal disinfection during labour for reducing the risk of mother-to-child transmission of HIV infection

BACKGROUND

Mother-to-child transmission (MTCT) of HIV infection is one of the most tragic consequences of the HIV epidemic, especially in resource-limited countries, resulting in about 650 000 new paediatric HIV infections each year world-wide. The paediatric HIV epidemic threatens to seriously undermine decade-old child survival programmes. This is one of several reviews assessing the available evidence for preventing HIV transmission from an HIV-infected woman to her child. The other reviews assess the effects of antiretroviral therapy, Caesarean section delivery, breast feeding, and vitamin A supplementation.

OBJECTIVES

To estimate the effect of vaginal lavage on the risk of MTCT of HIV and infant and maternal mortality and morbidity, as well as tolerability of vaginal lavage in HIV infected women.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register, Cochrane Pregnancy and Childbirth Register, PubMed, EMBASE, AIDSLINE, LILACS, AIDSTRIALS, and AIDSDRUGS, using standardised methodological filters for identifying trials. We also searched reference lists of identified articles, relevant editorials, expert opinions and letters to journal editors, and abstracts and proceedings of relevant conferences, and contacted subject experts and pharmaceutical companies. There were no language restrictions.

SELECTION CRITERIA

Randomised trials or clinical trials comparing vaginal disinfection during labour with placebo or no treatment, in known HIV infected pregnant women. Trials had to include an estimate of the effect of vaginal disinfection on MTCT of HIV and/or any other pre-specified adverse pregnancy outcome to be included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial eligibility and quality, and extracted data.

MAIN RESULTS

Only one low quality trial included an estimate of the effect of vaginal disinfection on at least one pre-specified outcome. There was no evidence of an effect of vaginal disinfection on MTCT of HIV (odds ratio 0.93, 95% confidence interval 0.63 to 1.38), and no information was available on the other pre-specified outcomes.

REVIEWER'S CONCLUSIONS

There is a need for well-designed randomised controlled trials to estimate the effects of vaginal disinfection on MTCT of HIV.

Titrated oral misoprostol solution for induction of labour: a multi-centre, randomised trial

OBJECTIVES

To determine the effects of titrated oral misoprostol solution, compared with vaginal dinoprostone.

STUDY DESIGN

Open, randomised clinical trial.

SETTING

Academic hospitals in South Africa and Liverpool, UK.

METHODS

Women undergoing induction of labour after 34 weeks of pregnancy were allocated by randomised, sealed opaque envelopes, to induction of labour with titrated oral misoprostol solution, or two doses of vaginal dinoprostone (2mg) administered six hours apart. Failure to deliver within 24 hours of randomisation was the primary outcome on which the sample size was based. The data were analysed by intention-to-treat.

RESULTS

Six hundred and ninety-five women were randomly allocated: 346 to oral misoprostol and 349 to vaginal dinoprostone. There were no significant differences in substantive outcomes. Vaginal delivery within 24 hours was not achieved in 38% of women in the oral misoprostol group and 36% in the vaginal dinoprostone group (RR 1.08; 95% CI 0.89-1.31). The caesarean section rates were 16% and 20%, respectively (RR 0.80; 95% CI 0.58-1.11). Hyperstimulation with fetal heart rate changes occurred in 4% of women in the oral misoprostol group and 3% after vaginal dinoprostone (RR 1.32, 95% CI 0.59-2.98). The response to induction of labour in women with unfavourable cervices was somewhat slower with misoprostol when membranes were intact, and with dinoprostone when membranes were ruptured. There were no differences in neonatal outcome between the two groups.

CONCLUSIONS

This new approach to oral misoprostol administration was successful in minimising the risk of uterine hyperstimulation, which has been a feature of misoprostol use for induction of labour, at the expense of a somewhat slower response in women with intact membranes and unfavourable cervices. Misoprostol is not registered for use in pregnant women, and further research is needed to confirm optimal and safe dosages.

Interventions aimed at decreasing the risk of mother-to-child transmission of HIV infection

BACKGROUND

At the end of 1998 over 33 million people were infected with the human immunodeficiency virus (HIV) and over one million children had been infected from their mothers.

OBJECTIVES

The objective of this review was to assess what interventions may be effective in decreasing the risk of mother-to-child transmission of HIV infection as well as their effect on neonatal and maternal mortality and morbidity.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register were searched.

SELECTION CRITERIA

Randomised trials comparing any intervention aimed at decreasing the risk of mother-to-child transmission of HIV infection compared with placebo or no treatment, or any two or more interventions aimed at decreasing the risk of mother-to-child transmission of HIV infection.

DATA COLLECTION AND ANALYSIS

Trial quality assessments and data extraction were undertaken by the reviewer.

MAIN RESULTS

Zidovudine Four trials comparing zidovudine with placebo involving 1585 participants were included. Compared with placebo, there was a significant reduction in the risk of mother-to-child transmission with any zidovudine (relative risk (RR) 0.54, 95% confidence interval (CI) 0.42-0.69). There is no evidence that 'long course therapy' is superior to 'short course therapy'. Nevirapine One trial compared intrapartum and postnatal nevirapine with intrapartum and postnatal zidovudine in 626 women, the majority of whom breast fed their infants. Compared with zidovudine, there was a significant reduction in the risk of mother-to-child transmission of HIV with nevirapine (RR 0.58, 95% CI 0.40-0.83). No trials are available comparing nevirapine with placebo. Caesarean section One trial comparing elective caesarean section with anticipation of vaginal delivery involving 436 participants was included. Compared with vaginal delivery, there was a significant reduction in the risk of mother-to-child transmission of HIV infection with caesarean section (RR 0.17, 95% CI 0.05-0.55). Immunoglobulin One trial comparing hyperimmune immunoglobulin plus zidovudine with non-specific immunoglobulin plus zidovudine involving 501 participants was included. The addition of hyperimmune immunoglobulin to zidovudine does not appear to have any additional effect on the risk of mother-to-child transmission (RR 0.67, 95% CI 0.29-1.55).

REVIEWER'S CONCLUSIONS

Zidovudine, nevirapine and delivery by elective caesarean section appear to be very effective in decreasing the risk of mother-to-child transmission of HIV infection.

Interventions for treating genital chlamydia trachomatis infection in pregnancy

BACKGROUND

Chlamydia trachomatis is a sexually transmitted infection. Mother-to-child transmission can occur at the time of birth and may result in ophthalmia neonatorum or pneumonitis in the newborn.

OBJECTIVES

The objective of this review was to assess the effects of antibiotics in the treatment of genital infection with Chlamydia trachomatis during pregnancy with respect to neonatal and maternal morbidity.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register (Cochrane Library issue 1, 1999).

SELECTION CRITERIA

Randomised trials of any antibiotic regimen compared with placebo or no treatment or alternative antibiotic regimens in pregnant women with genital Chlamydia trachomatis infection.

DATA COLLECTION AND ANALYSIS

Trial quality assessments and data extraction were done independently by two reviewers. Study authors were contacted for additional information.

MAIN RESULTS

Eleven trials were included. Trial quality was generally good. Amoxycillin appeared to be as effective as erythromycin in achieving microbiological cure (odds ratio 0.54, 95% confidence interval 0.28 to 1.02). Amoxycillin was better tolerated than erythromycin (odds ratio 0.16, 95% confidence interval 0.09 to 0.30). Clindamycin and azithromycin also appear to be effective, although the numbers of women included in trials are small.

REVIEWER'S CONCLUSIONS

Amoxycillin appears to be an acceptable alternative therapy for the treatment of genital chlamydial infections in pregnancy when compared with erythromycin. Clindamycin and azithromycin may be considered if erythromycin and amoxycillin are contra-indicated or not tolerated.

Interventions for treating gonorrhoea in pregnancy

BACKGROUND

Neisseria gonorrhoeae can be transmitted from the mother's genital tract to the newborn during birth and can cause gonococcal opthalmia neonatorum.

OBJECTIVES

The objective of this review was to assess the effects of antibiotic regimens in the treatment of genital infection with gonorrhoea during pregnancy with respect to neonatal and maternal morbidity.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register were searched. Date of last search: October 1998.

SELECTION CRITERIA

Randomised trials of one regimen of antibiotic versus another in pregnant women with culture confirmed genital gonococcal infection.

DATA COLLECTION AND ANALYSIS

Eligibility and trial quality were assessed by one reviewer.

MAIN RESULTS

Two trials involving 329 women were included. Amoxycillin with probenicid or spectinomycin or ceftriaxone have a similar effect on microbiological cure, defined by negative gonococcal culture.

REVIEWER'S CONCLUSIONS

Any of the antibiotic regimens tested in these trials appear to be effective for the treatment of gonorrhoea in pregnancy in terms of their effect on microbiological cure. For women who are allergic to penicillin, this review provides reassurance that treatment with ceftriaxone or spectinomycin appears to be at least as equally effective in producing microbiological cure.

Are we prescribing multiple courses of antenatal corticosteroids? A survey of practice in the UK

A postal questionnaire concerned with prescribing antenatal corticosteroids was sent to one named clinician at each of 279 obstetric units in the UK. They were asked whether their unit prescribed repeated courses, the indications for which these would be prescribed, the interval between courses, the drugs and regimens used and whether they would be willing to participate in a proposed randomised controlled trial. The response rate was 75%. Of the respondents, 98% prescribed repeated courses; the indications most commonly cited by units who prescribed steroids were prelabour spontaneous rupture of membranes (84.2%) and suspected preterm labour (81.8%). 70.6% of units were willing to participate in the proposed trial.

The association between maternal HIV infection and perinatal outcome: a systematic review of the literature and meta-analysis

OBJECTIVE

To investigate the association between maternal HIV infection and perinatal outcome by a systematic review of the literature and meta-analysis.

METHODS

Appropriate publications were identified using electronic and hand searching of relevant journals from 1983 to 1996. Studies were included in the review if they were prospective cohorts with pregnant women identified as being HIV-infected with a control group of pregnant women who were not infected with HIV. Methodological quality was assessed for each study. Data were extracted for pre-determined outcome measures. Sensitivity analyses were performed to explore the association between HIV infection and an adverse perinatal outcome for the following study characteristics: clinical setting (developed or developing countries), methodological quality (high or poor) and whether studies controlled for potential confounding.

RESULTS

Thirty-one studies were eligible to be included in the review. The summary odds ratio of the risk of pre-defined adverse perinatal outcomes related to maternal HIV infection were as follows: spontaneous abortion 4.05 (95% CI 2.75-5.96); stillbirth 3.91 (95% CI 2.65-5.77); fetal abnormality 1.08 (95% CI 0.7-1.66); perinatal mortality 1.79 (95% CI 1.14-2.81); neonatal mortality 1.10 (95% CI 0.63-1.93); infant mortality 3.69 (95% CI 3.03-4.49); intrauterine growth retardation 1.7 (95% CI 1.43-2.02); low birthweight 2.09 (95% CI 1.86-2.35) and pre-term delivery 1 83 (95% CI 1.63-2.06). Sensitivity analyses showed that the association between infant mortality and maternal HIV infection was stronger in studies conducted in developing countries when compared with developed countries [odds ratios (OR) 3.72 (95% CI 3.05-4.54) and 8.6 (95% CI 0.53-141.05), respectively]; studies of higher methodological quality compared with those of poorer quality [odds ratios 14.57 (95% CI 6.93-30.65) and 3.37 (95% CI 2.74-4.14), respectively] and studies which had used restriction or matching to control for potential confounding factors compared with those that had not [OR 11.60 (95% CI 5.71-23.58) and 3.35 (95% CI 2.73-4.12), respectively].

CONCLUSIONS

The findings of this review have implications for women infected with HIV who are planning a pregnancy or who find themselves pregnant. There appears to be an association, although not strong, between maternal HIV infection and an adverse perinatal outcome. This relationship may be due to bias including uncontrolled or residual confounding. There does, however, appear to be a real and large increase in the risk of infant death in developing countries associated with maternal HIV infection, especially so when there has been an attempt to control for confounding.

The effect of pregnancy on survival in women infected with HIV: a systematic review of the literature and meta-analysis

OBJECTIVE

To investigate the effect of pregnancy on disease progression and survival in women infected with HIV by a systematic review of the literature and meta-analysis.

METHODS

Appropriate publications were identified using electronic and hand searching of relevant journals from 1983 to 1996. Studies were included in the review if they were cohort studies, either prospective or retrospective, or case-control studies which investigated disease progression of pregnant women infected with HIV and included a control group of non-pregnant women infected with HIV for comparison. Methodological quality was assessed for each study. Data were extracted for predetermined outcome measures. Sensitivity analyses were performed to explore the association between pregnancy and disease progression for the following study characteristics: clinical setting (developed or developing countries), methodological quality (high or poor) and whether studies had controlled for potential confounding.

RESULTS

Seven studies, all prospective cohorts, were eligible to be included in the review. The summary odds ratio for the risk of an adverse maternal outcome related to HIV infection and pregnancy were as follows: death 1.8 (85% CI 0.99-3.3); HIV disease progression 1.41 (95% CI 0.85-2.33); progression to an AIDS-defining illness 1.63 (95% CI 1.00-2.67) and fall of CD4 cell count to below 200 x 10(6)/L 0.73 (95% CI 0.17-3.06). Sensitivity analyses showed that HIV progression in pregnancy was significantly more common in a developing country setting (odds ratio 3.71, 95% CI 1.82-7.75) than in developed countries (odds ratio 0.55, 95% 0.27-1.11) and also significantly more common in high quality studies when compared to low quality ones, odds ratios 3.71 (95% CI 1.82-7.57) and 0.55 (95% CI 0.27-1.11), respectively. However, there appears to be less progression of HIV disease and progression to AIDS when studies attempted to control for confounding by matching or restriction techniques, although this was not statistically significant in either case.

CONCLUSIONS

The findings of this review have implications for women infected with HIV who are pregnant or are considering a pregnancy. There does appear to be an association between adverse maternal outcomes and pregnancy in women infected with HIV, although this association is not strong. The relation may be due to the result of bias including residual confounding. Further large scale observational studies with long term follow up are required before this issue can be fully resolved.