Limited data suggest that HIV-infected pregnant women develop postpartum viral rebound. However, viral load changes in the postpartum period have not been adequately characterized. Changes in adherence to antiretroviral therapy, pregnancy-related changes in pharmacokinetics of antiretroviral medications, and decline in immune competence are mechanisms by which postpartum viral load rebound may occur. This study is designed to characterize the incidence and magnitude of postpartum viral rebound during the initial 24 weeks postpartum and to explore the mechanisms and consequences of viral rebound.

Eligible patients are evaluated at gestational weeks 34 and 36, at delivery, and at regular visits for 96 weeks postpartum. Most evaluations include a medical history, physical exam, laboratory tests, and adherence and quality-of-life questionnaires. Viral load and CD4/CD8 cell counts are measured frequently. Patients are expected to receive at least 8 weeks of stable HAART before delivery, and to continue HAART throughout the remainder of the study. The choice of HAART is left to the primary provider. No antiretroviral drugs are provided by this study.

Patients participating in the A5153s substudy receive either NFV or LPV/r as part of their HAART. Pharmacokinetic blood sampling takes place at 36 weeks gestation, 6 weeks postpartum, and 24 weeks postpartum. Patients record the administration times and doses of their NFV or LPV/r for 48 hours prior to each substudy visit, and hold their regularly scheduled doses of antiretroviral medications on substudy days. Patients arrive at the clinic fasting (no food or drink for the previous 8 hours) and are given a standardized breakfast prior to supervised administration of their NFV or LPV/r dose. An intravenous catheter is placed in an arm vein for blood collection at pre-dose and 1, 2, 4, and 6 hours post-dose.