['To determine the effects of duration of ruptured membranes (DRM) and duration of labor in HIV transmission.', 'A retrospective cohort study of 366 HIV-infected pregnant women and their infants analyzed the effects of these two variables; the cut-off point for transmission increase was estimated using a ROC curve. A multivariate analysis was performed with the most important risk factors according to the literature: maternal age, lymphocyte count, use of invasive procedures during gestation, antiretroviral treatment during pregnancy and labor, mode of delivery, newborn weight, DRM, labor duration, and the interaction of these last two factors.', 'The cut-off points were estimated at 6 h for DRM and at 5 h for labor duration. A lymphocyte count below 500 cells/ml, use of invasive procedures, use of antiretroviral treatment during pregnancy and interaction between DRM, and labor duration remained significant in perinatal HIV transmission (P<0.05).'] Are duration of ruptured membranes and extended labor risk factors for HIV transmission?