In clinical trials being conducted throughout the world, pregnant HIV-infected women are given anti-HIV drugs before, during, and after they give birth to prevent mother-to-child transmission of HIV. However, the effects of this anti-HIV treatment on infants is unknown. The purpose of this study is to determine the safety, toxicity, and potential side effects of maternal anti-HIV treatment on infants born to these HIV-infected women.

Study hypothesis: Specific combination antiretroviral regimens used in clinical trials in diverse areas of the world are safe and well tolerated during pregnancy and breastfeeding periods, and are not associated with adverse side effects to the fetus, neonate, and/or breastfeeding infant. These regimens are associated with reduction of mother-to-child HIV transmission.

Many HIV-infected women outside the United States enroll in clinical trials that provide them antiretroviral therapy (ART) to prevent mother-to-child transmission of HIV. However, data are limited on the safety, toxicity, and adverse effects that maternal ART may have on infants born to HIV-infected women. This study will monitor the adverse effects and potential benefits of maternal ART on these infants.

No antiretrovirals will be given in this study. This study will last 18 months. Infants will be enrolled in the study within 48 hours of birth. There will be 6 study visits starting at study entry and every 6 weeks thereafter. Infants will undergo blood and urine collection, and medical history assessments will occur at every visit. Mothers will also be evaluated at these visits.

Inclusion Criteria:

• Infant born to HIV-1 infected mother enrolled in NIH-sponsored, international antiretroviral treatment trial AND who has had either in utero or postpartum antiretroviral exposure
• Parent or guardian willing to provide informed consent

Exclusion Criteria:

• Infant with no exposure to antiretrovirals OR who received only intrapartum antiretroviral exposure

Infants born to HIV-infected women