Background: The World Health Organization recommends routine vitamin A supplementation during pregnancy or lactation in areas with endemic vitamin A deficiency (where night blindness occurs), based on the expectation that supplementation will improve maternal and newborn outcomes including mortality, morbidity and prevention of anaemia or infection.
Objectives: To review the effects of supplementation of vitamin A, or one of its derivatives, during pregnancy, alone or in combination with other vitamins and micronutrients, on maternal and newborn clinical outcomes.
Search strategy: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (15 July 2010).
Selection criteria: All randomised or quasi-randomised trials, including cluster-randomised trials, evaluating the effect of vitamin A supplementation in pregnant women.
Data collection and analysis: Two review authors independently assessed all studies for inclusion and resolved any disagreement through discussion with a third person. We used pre-prepared data extraction sheets.
Main results: We examined 88 reports of 31 trials, published between 1931 and 2010, for inclusion in this review. We included 16 trials, excluded 14, and one is awaiting assessment.Overall when trial results are pooled, Vitamin A supplementation does not affect the risk of maternal mortality (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.55 to 1.10, 3 studies, Nepal, Ghana,UK ), perinatal mortality, neonatal mortality, stillbirth, neonatal anaemia, preterm birth or the risk of having a low birthweight baby. Vitamin A supplementation reduces the risk of maternal night blindness (risk ratio (RR) 0.70, 95% CI 0.60 to 0.82, 1 trial Nepal). In vitamin A deficient populations and HIV-positive women, vitamin A supplementation reduces maternal anaemia (risk ratio (RR) 0.64, 95% confidence interval (CI) 0.43 to 0.94, 3 trials, Indonesia, Nepal,Tanzania ). There is evidence that vitamin A supplements may reduce maternal clinical infection (RR 0.37, 95% CI 0.18 to 0.77, 3 trials, South Africa, Nepal and UK).In HIV-positive women vitamin A supplementation given with other micronutrients was associated with fewer low birthweight babies (< 2.5 kg) in the supplemented group in one study (RR 0.67, CI 0.47 to 0.96).
Authors' conclusions: The pooled results of two large trials in Nepal and Ghana (with almost 95,000 women) do not currently suggest a role for antenatal vitamin A supplementation to reduce maternal or perinatal mortality. However the populations studied were probably different with regard to baseline vitamin A status and there were problems with follow-up of women. There is good evidence that antenatal vitamin A supplementation reduces maternal anaemia for women who live in areas where vitamin A deficiency is common or who are HIV-positive. In addition the available evidence suggests a reduction in maternal infection, but these data are not of a high quality.