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.