The objective of this Ph.D thesis is to describe the care received by HIV-infected pregnant women in France in the era of multitherapy, to assess how actual practices differ from recommendations, to identify factors related to non optimal care for prevention of mother-to child HIV transmission (PMTCT) and to improve recommendations for some minority situations that have not been well evaluated.Work for this thesis was done using data from the French perinatal cohort ANRS-EPF, the only national multicenter cohort and one of the largest, having included 17 491 mother-child couples since 1986.Currently, almost all women are treated with multitherapy (96.5% in 2009) and the transmission rate is below 1% (0.6%; 95%CI: 0.2-1.4). Non optimal care for PMTCT (late HIV diagnosis, lack or late initiation of antiretroviral treatment during pregnancy, intrapartum and postnatal prophylaxis, virological failure at delivery, vaginal delivery despite uncontrolled viral load, maternal breastfeeding) has become increasingly rare in France (between 0.2% and 5.5% in 2009). The cesarean section rate is however clearly higher than in the general population, most notably due to a higher rate of elective cesarean section among women with a controlled viral load, which does not comply with the recommendations. And yet elective cesarean section performed on women with a controlled viral load does not result in a lower transmission rate.Migration from a sub-Saharan African country is associated with a later HIV diagnosis during pregnancy, but access to PMTCT and adherence seem similar once HIV infection is diagnosed. Failure for a mother to disclose her HIV status to the child’s father, which occurs more frequently with African women, is associated with less optimal PMTCT strategies but without any increase in MTCT rate.We have also evaluated the recommendations for some minority situations. For HIV-2infected women (2% of EPF cohort), who had a spontaneously lower MTC rate, our results contribute to justifying a less intensive PMTCT than for HIV-1 infected women. For women needing an amniocentesis, which, before the multitherapy era, was associated with an increased transmission rate, our results suggest that the transmission risk is no longer greater for women being treated by multitherapy.Our findings are encouraging as they demonstrate the effectiveness of a health care system which promoting free universal access to HIV care has succeeded in reaching out the most under privileged populations, thereby making it easier for them to receive optimal care although they remain at risk for non optimal PMTCT practices.