From January 1986 to December 1990 70 HIV-seropositive pregnant women were seen at the Department of Obstetrics and Gynecology, Rome, Italy. All of them delivered in our Hospital Center and their babies were enrolled in pediatric follow-up. Sixty-five patients (93%) were drug-addicted, only 6 of them showing signs of HIV infection (lymphoadenopathy). The authors report the results of a clinical study demonstrating that asymptomatic HIV infection did not affect the regular course of pregnancy. Moreover, they show that there was no progression of disease during pregnancy, vertical transmission was 24%, the infected babies were of low birth weight (2,586 +/- 527 vs. 3,100 +/- 470 g) and the incidence of premature delivery was higher (30 vs. 8%) than in noninfected controls.