Background: Approximately 800,000 HIV-infected infants are born each year, two thirds of them in sub-Saharan Africa. The rate of HIV transmission from mother to infant is estimated at 13-48% in the absence of antiretroviral treatment. Interventions currently available to prevent mother to child transmission in resource-limited settings among breastfeeding populations child HIV transmission during the breastfeeding period. Because safe alternatives to breastfeeding are not currently a viable option for many HIV-infected women in sub-Saharan Africa, it is important to identify interventions to decrease transmission to the infant during this period.