Objective: We attempted to determine whether the risk of mother-to-child transmission of human immunodeficiency virus type 1 is related to events in pregnancy, labor, and delivery.
Study design: In a prospective multicenter cohort study of human immunodeficiency virus type 1-infected mothers and their children, we studied pregnancy histories, labor (including gestational age, induction, membrane rupture, length of labor, intrapartum procedures, bleeding, infection, antiseptic technique, and antiretroviral therapy), and conditions of delivery.
Results: Among 1632 singleton infants, 310 were confirmed infected with human immunodeficiency virus type 1 at age 18 months (19.0% +/- 1.9%). Procedures (in particular, amniocentesis and amnioscopy) and sexually transmitted diseases during pregnancy, preterm delivery, premature membrane rupture, hemorrhage in labor, and bloody amniotic fluid were associated with increased transmission. Transmission was not related to mode of delivery or to the conditions of labor and delivery.
Conclusions: Transmission was not decreased after emergency or elective cesarean section. Most risk factors either were rare or appeared poorly amenable to obstetric management, with the exception of invasive procedures, which should be avoided.