Women who did not meet WHO criteria for initiation of ART for their own HIV infections were considered eligible for each ARV and feeding strategy. During the period from 10 weeks of gestation through 18 months postpartum, each of the depicted events occurred based on probabilities derived from the published literature: intrauterine (IU) demise or HIV infection, intrapartum or early postpartum (IP) HIV infection, postpartum (PP) HIV infection, or neurologic mitochondrial toxicity (MT), resulting in the outcomes depicted at the end of each path.