Objective:To describe the impact of HIV diagnosis on contraception, incidence of pregnancy and live-births among HIV-infected women in France.Design:Follow-up of women included in a French cohort of HIV-infected adults (SEROCO).Methods:In 17 hospital-based units and one private practitioners’ network in the Paris area and south-east region of France, 412 HIV-infected women (volunteers) were enrolled from 1988 to 1993, shortly after HIV diagnosis (median, 3 months), and followed for a median of 3 years. The main outcome measures were incidence and outcome of pregnancy, proportions of women sexually active and methods of contraception.Results:The incidence of pregnancy decreased significantly from 20.4 per 100 person-years in the year preceding HIV diagnosis to 7.9 per 100 person-years after HIV diagnosis (P < 0.001), whereas the proportion of pregnancies voluntarily interrupted doubled (63 versus 29%). The proportion of women who were sexually inactive increased from 5% before HIV diagnosis to 20% thereafter. During follow-up, 80% of sexually active women were using contraceptive methods.Conclusions:The study supports an association between the discovery of HIV infection and a decrease in the proportion of women who are sexually active, a decrease in the incidence of pregnancy in general and live-births in particular, and an increase in the proportion of pregnancies voluntarily interrupted. Nevertheless, 24% of the women became pregnant and around 20% of sexually active women were not using any contraception. The high rate of voluntary abortion may indicate that many of these pregnancies were unplanned and could have been prevented.