This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This is a prospective study to describe the pharmacokinetic parameters during pregnancy of selected antiretroviral drugs currently used in the clinical care of pregnant HIV infected women and to determine if therapeutic dosing regimes of these antiretroviral drugs produce adequate drug exposure during pregnancy compared to a)historical data from non-pregnant adults;and b) the same women in the study cohorts during the post-partum period. The secondary objectives rare to compare antiretroviral drug concentrations in plasma from cord blood in those in maternal plasma at the time of delivery and to indirctly assess the induction of cytochrome P450 3A4 by determining the ratio in urine of 6B-hydroxycortisol to cortisol.