A study conducted in Tanzania has demonstrated that HIV-positive pregnant women who receive a multivitamin supplement have much less risk of bearing low birth-weight babies and delivering prematurely. Furthermore, their babies are less likely to become infected with HIV^[1][2]. These children are also significantly heavier at two years after continued vitamin supplementation during breastfeeding^[3].

Providing vitamins B, C and E to these mothers significantly reduced both HIV transmission to the babies and mortality in the first two years of life, when the mothers immunological or nutritional status was poor. The study also found that women who received the multivitamin had substantial and sustained increases in CD4 and CD8 cell counts.

In contrast, providing vitamin A to the mothers appeared to increase HIV transmission rates and was therefore discontinued, although the risk of pneumonia among the babies was lower if their mothers had taken vitamin A. An earlier study had shown that vitamin A deficiency was associated with increased transmission of HIV^[4][5][6].

Another placebo-controlled study from the Tanzanian group has reported that HIV-infected infants given vitamin A supplements have improved growth and weight gain compared to those given placebo. Furthermore, vitamin A supplements reduce the risk of stunting associated with persistent diarrhoea in HIV-infected infants^[7].

Several other groups have reported that vitamin A supplements alone have no effect on mother-to-child HIV transmission^[8]. A large South African study has found that vitamin A supplements do not reduce the overall risk of mother-to-baby HIV transmission. However, women taking the supplement were less likely to have early deliveries. Furthermore, preterm babies born to these women were less likely to be HIV-infected than preterm babies born to women in the placebo group^[9].

Analysis of 334 HIV-positive mothers in Malawi found that vitamin A supplementation had no significant effect on mother-to-child transmission at six weeks and twelve months, or on breast milk viral load^[10].

The significance of these results is unclear for Europe and North America, because they may represent an improvement in nutrient status to the level normally seen in Europe and North America, so there may be no justification for supplementing at this level if dietary intake is adequate. Further supplementation may not result in a corresponding improvement in immune status.