Clinical Trials That Have Changed Clinical Practice and Care of Pregnant People With HIV.

Over the last 4 decades, significant advances in the care of HIV during pregnancy have successfully reduced, and nearly eliminated, the risk of perinatal HIV transmission. The baseline risk of transmission without intervention (25% to 30%) is now <1% to 2% in the United States with contemporary antepartum, intrapartum, and postnatal interventions. In this review, we discuss 3 landmark clinical trials that substantially altered obstetric practice for pregnant individuals with HIV and contributed to this extraordinary achievement: 1) the Pediatric AIDS Clinical Trials Group 076 Trial determined that antepartum and intrapartum administration of antiretroviral drug zidovudine to the pregnant individual, and postnatally to the newborn, could reduce the risk of perinatal transmission by approximately two-thirds; 2) the European Mode of Delivery Collaboration Trial demonstrated performance of a prelabor cesarean birth before rupture of membranes among pregnant people with viremia reduced the risk of perinatal transmission compared with vaginal birth; and 3) the International Maternal Pediatric Adolescent AIDS Clinical Trials Network 2010 Trial identified that dolutegravir-containing, compared with efavirenz-containing, antiretroviral regimens during pregnancy achieved a significantly higher rate of viral suppression at delivery with shorter time to viral suppression, with fewer adverse pregnancy outcomes. Collectively, these trials not only advanced obstetric practice but also advanced scientific understanding of the timing, mechanisms, and determinants of perinatal HIV transmission. For each trial, we will describe key aspects of the study protocol and outcomes, insights gleaned about the dynamics of perinatal transmission, how each study changed clinical practice, and relevant updates to current practice since the trial's publication.