Using oral clindamycin to treat women with asymptomatic bacterial vaginosis during their second trimester (between 12 and 22 weeks estimated gestational age) reduces the number of premature births and late miscarriages. The study did not demonstrate a difference in the number of neonatal intensive care unit admissions, mean birth weight, or gestational age. This is the first study demonstrating benefits in treating asymptomatic bacterial vaginosis early in pregnancy. It still needs to be determined, in larger trials, whether generalized screening and treatment for asymptomatic bacterial vaginosis in the early second trimester is beneficial and cost-effective.