• Proportion of women in each treatment group with virologic suppression to less than 400 copies/ml at 34th week of pregnancy (or last viral load prior to delivery, if delivery occurs before 34th week of pregnancy) while continuing on assigned therapy [ Time Frame: at Week 34 of pregnancy ] [ Designated as safety issue: No ]
  

• Primary outcome, evaluating ART naive and ART experienced women [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• HIV-related health status of women at delivery, determined by CD4 counts and plasma HIV-1 viral load in the two treatment groups and in ART naive and ART experienced women [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• study treatment adherence and health status by self report [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• HIV-related health status of women postpartum, determined by CD4 counts and plasma HIV-1 viral load [ Time Frame: at Months 3, 6 and 12 postpartum and prior to ART treatment ] [ Designated as safety issue: Yes ]
  
• development of HIV-1 genotypic resistance among women in each treatment group [ Time Frame: at delivery, Months 3, 6, and 12 postpartum, and in all cases of treatment failure ] [ Designated as safety issue: No ]
  
• incidence of abnormal glucose tolerance, gestational diabetes, and abnormal lactate levels during pregnancy in each treatment group [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• incidence of anemia, hypoglycemia, abnormal liver function studies, prematurity, low birth weight, or perinatal HIV transmission among infants born to women in each treatment group [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• predictive value, sensitivity, and specificity of polymorphisms in HLA-B57, HLA-DR7, and HLA-DQ3 in identifying pregnant women at risk for development of ABC hypersensitivity [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• concentration of T cell receptor rearrangement excision DNA circles [ Time Frame: at study entry, delivery and 6 weeks postpartum ] [ Designated as safety issue: No ]
  

Antiretroviral therapy (ART) in pregnancy has dramatically reduced the rates of perinatal HIV transmission. Many pregnant women infected with HIV may not meet the criteria for treatment as set forth by the Department of Health and Human Services' guidelines and would not be started on therapy if they were not pregnant. Pregnant women are prescribed a variety of treatment regimens; the optimum regimen for pregnant women who plan to discontinue therapy after delivery is unknown. An optimum regimen would account for the need for maximum viral suppression, minimal fetal toxicity, and preservation of future therapeutic options for the mother. This study will compare an all nucleoside reverse transcriptase inhibitor (NRTI) regimen of ABC/3TC/ZDV with a standard protease inhibitor (PI) regimen of LPV/RTV and 3TC/ZDV. This study was initially designed for women who plan to take antiretrovirals only while pregnant and do not meet the criteria for treatment initiation if not pregnant. However, pregnant women who have taken ART for 180 days or less or have taken ZDV monotherapy for a total of 8 weeks or less prior to entering this study are eligible for Version 2.0 of this study.

Women in this study will be randomly assigned to one of two groups. Women in Group A will receive one pill ABC/3TC/ZDV twice a day. Women in Group B will receive one pill 3TC/ZDV and 4 pills LPV/RTV twice a day. Women will take their assigned medications until they go into labor. Once in labor, women will be given zidovudine through intravenous (IV) infusion; they will stop taking oral zidovudine but will continue with their other medications. After delivery, all infants will be given zidovudine for six weeks.

Women will have study visits every 2 weeks for the first 8 weeks of treatment, and then every 4 weeks until Week 28. Depending on where a woman is in her pregnancy when she enrolls in the study, she will also have study visits at Weeks 20, 28, and 34 of her pregnancy. At each visit, women will have a medical interview, a physical exam, and an obstetrical exam; blood and urine collection will occur at these visits. Mothers will undergo a fetal ultrasound at Week 20. Adherence, health status, and behavior assessments will occur at selected visits prior to delivery.

After delivery, women will stop taking the study medications but will continue to have study visits at approximately 6, 12, 24, 36, 48, and 52 weeks after delivery. Medical history and a physical exam will occur at all visits for mothers postpartum. Blood collection will occur at every postpartum visit; urine collection will occur 12, 24, and 48 weeks postpartum; health status and behavior assessments will occur at most visits postpartum. Infants will have study visits at 2, 16, and 24 weeks after birth. A medical history, physical exam, and laboratory tests will be conducted at the infant study visits. Women will also be asked to enroll their infants in PACTG 219C, a long-term study that follows infants who are born to HIV infected mothers.