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

BACKGROUND

Observational studies of pregnant women in sub-Saharan Africa have shown that low serum vitamin A levels are associated with an increased risk of mother-to-child transmission (MTCT) of HIV. Vitamin A is cheap and easily provided through existing health services in low-income settings. It is thus important to determine the effect of routine supplementation of HIV positive pregnant or breastfeeding women with this vitamin on the risk of MTCT of HIV, which currently results in more than 1000 new HIV infections each day world-wide.

OBJECTIVES

We aimed to assess the effect of antenatal and or postpartum vitamin A supplementation on the risk of MTCT of HIV as well as infant and maternal mortality and morbidity.

SEARCH STRATEGY

In June 2010 we searched the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, AIDS Education Global Information System, and WHO International Clinical Trials Registry Platform; and checked reference lists of identified articles for any studies published after the earlier version of this review was updated in 2008.

SELECTION CRITERIA

We selected randomised controlled trials conducted in any setting that compared vitamin A supplementation with placebo in known HIV-infected pregnant or breastfeeding women.

DATA COLLECTION AND ANALYSIS

At least two authors independently assessed trial eligibility and quality and extracted data. We calculated relative risks (RR) or mean differences (MD), with their 95% confidence intervals (CI) for each study. We conducted meta-analysis using a fixed-effects method (when there was no significant heterogeneity between study results, i.e. P>0.1) or the random-effects method (when there was significant heterogeneity), and report the Higgins' statistic for all pooled effect measures.

MAIN RESULTS

Five randomised controlled trials which enrolled 7,528 HIV-infected women (either during pregnancy or the immediate postpartum period) met our inclusion criteria. These trials were conducted in Malawi, South Africa, Tanzania, and Zimbabwe between 1995 and 2005. We combined the results of these trials and found no evidence that vitamin A supplementation has an effect on the risk of MTCT of HIV (4 trials, 6517 women: RR 1.04, 95% CI 0.87 to 1.24; I(2)=68%). However, antenatal vitamin A supplementation significantly improved birth weight (3 trials, 1809 women: MD 89.78, 95%CI 84.73 to 94.83; I(2)=33.0%), but there was no evidence of an effect on preterm births (3 trials, 2110 women: RR 0.88, 95%CI 0.65 to 1.19; I(2)=58.1%), stillbirths (4 trials, 2855 women: RR 0.99, 95%CI 0.68 to 1.43; I(2)=0%), deaths by 24 months (2 trials, 1635 women: RR 1.03, 95%CI 0.88 to 1.20; I(2)=0%), postpartum CD4 levels (1 trial, 727 women: MD -4.00, 95% CI -51.06 to 43.06), and maternal death ( 1 trial, 728 women: RR 0.49, 95%CI 0.04 to 5.37).

AUTHORS' CONCLUSIONS: Current best evidence shows that antenatal or postpartum vitamin A supplementation probably has little or no effect on mother-to-child transmission of HIV. According to the GRADE classification, the quality of this evidence is moderate; implying that the true effect of vitamin A supplementation on the risk of mother-to-child transmission of HIV is likely to be close to the findings of this review, but that there is also a possibility that it is substantially different.