Published June, 2010

Antiretroviral Regimens in Pregnancy and Breast-Feeding in Botswana, R.L. Shapiro, M.D., et als., 362 N. Eng. J. Med. 2282-94 (2010)

This study reports strong evidence of the effectiveness of HIV antiretroviral therapy in substantially reducing the risk of HIV transmission from mother to child when taken by women during breastfeeding.

Breastfeeding is normally the best way to feed an infant and is a critical factor for improving child survival in developing nations. A woman infected with HIV whose newborn has no been infected during pregnancy, labor or delivery, however, still can transmit the virus to her child during breastfeeding. Nonetheless, the use of highly-active anti-retroviral therapy (HAART) in mothers to prevent transmission to children through breast-feeding, particularly in areas of the world where replacement feeding is neither safe nor feasible, had prior to this study remained an unproven strategy.

The authors compared different HAART regimens used in pregnancy and during breast-feeding to determine whether the regimens differ with respect to viral suppression that reduces the risk of transmission during pregnancy and breastfeeding, pregnancy outcomes, and toxic effects of using HAART while breastfeeding in mothers and infants.

The authors maintain that their findings suggest that the use of HAART in women from early in the third trimester of pregnancy through six months of breast-feeding is an effective strategy for preventing mother-to-child transmission while allowing for the benefits of breast-feeding.

The study also, however, confirmed the previously-observed associations between use of protease inhibitors during pregnancy and premature infant births; 23% of infacts in the protease inhibitor group were premature, while 15% were premature in the NRTI group. The incidence of low birth rate did not differ much among the different regimens but was fairly significant (13% to 17%) and twice as high as in a previous study of women who did not receive HAART to prevent mother-to-child transmission.

Because the study was limited to women with CD4+ cell counts of 200 cells per cubic millimeter or more, and the median viral load level was lower than that in many treatment settings, extrapolation of the results to women with lower CD4+ cell counts may be limited. The authors also stress that their study was not intended to answer some important policy questions regarding the prevention of mother-to-child transmission, including whether the use of HAART in women is superior to short-course AZT with prolonged nevirapine prophylaxis in infants during breast-feeding among women with higher CD4+ cell counts. However, the study results do strongly suggest that neither pregnancy nor breast-feeding adversely affects a woman's ability to maintain low HIV viral loads.