Transmission of the HIV from the mother to the offspring occurs in the process of pregnancy, childbirth, and breastfeeding. In fact, there is a 15-45% chance of the viral transmission through pregnancy ONLY if the mother and the newborn are not under anti-retroviral treatments. On the other hand, evidence indicates that regular thorough treatment actually reduces the risk of transmission to less than 1%.

This implies that the infant can have the benefit of exclusive breastfeeding with the nullified risk of contracting HIV infection. Source: Avert, WHO Would you advise an HIV positive mother under treatment to breastfeed her infant if she cannot afford formula milk?