New York — NEW YORK — HIV-infected women who breastfed without supplementing their infants' diets with other fluids or foods for the first six months of life had lower levels of the AIDS virus in their milk, a study in Zambia showed.
The findings, published Wednesday in Science Translational Medicine, are the first to show how variations in breast-feeding practices affect HIV levels in an infected mother's milk. Women who stopped breast feeding had "dramatically higher" levels of the virus, said Louise Kuhn, lead author of the study.
Early weaning hasn't been successful in preventing HIV transmission from mother to baby, and the study may help explain why, said Kuhn, an associate professor of epidemiology at Columbia University's Mailman School of Public Health in New York. While it's unknown why breastfeeding lowers HIV levels, researchers hypothesize the "hormonally regulated, demand- supply" cycle of frequent breastfeeding may influence HIV dynamics in breast milk.
"Weaning should be a slow and gradual process," Kuhn said in an email.
HIV-positive women who choose to breastfeed should adhere to their antiretroviral drug regimens and exclusively breastfeed through the first six months before gradually introducing complementary foods and continuing to breastfeed until they and their infants are ready to wean, Kuhn said.
Researchers looked at the breast milk of 958 HIV-infected women and their infants and followed them for two years. They were trying to determine whether shortening the duration of breastfeeding would reduce the risk of HIV transmission.
All the women were to breastfeed their babies for at least four months, then half the women were recommended to stop while the other half was encouraged to continue. The women had their breast milk collected at four and a half months, and the babies in the study were routinely tested for HIV transmission.