International Journal of Gynecology and Obstetrics 82 (2003) 17–23 0020-7292/03/$30.00  2003 International Federation of Gynecology and Obstetrics. Published by Elsevier Science Ireland Ltd. All rights reserved. doi:10.1016/S0020-7292Ž03.00123-1 Article Duration of ruptured membranes and extended labor are risk factors for HIV transmission A. Garcia-Tejedor*, A. Perales, V. Maiques Obstetrics Department, Hospital Materno-Infantil ‘La Fe’, Valencia, Spain Received 23 October 2002; received in revised form 10 February 2003; accepted 17 February 2003 Abstract Objectives: To determine the effects of duration of ruptured membranes (DRM) and duration of labor in HIV transmission. Methods: 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. Results: The cut-off points were estimated at 6 h for DRM and at 5 h for labor duration. A lymphocyte count below 500 cellsy 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). Conclusions: An increased DRM increased perinatal HIV transmission when it was associated with prolonged labor.  2003 International Federation of Gynecology and Obstetrics. Published by Elsevier Science Ireland Ltd. All rights reserved. Keywords: Ruptured membranes; Labor; Uterine contractions; Perinatal HIV transmission 1. Introduction Several studies highlighted that a longer dura- tion of ruptured membranes (DRM) was associated with an increased risk of mother-to-child transmis- sion of human immunodeficiency virus (HIV) w1– 6x. However, although the rupture of amniotic membranes allows fetal contact with maternal blood and potential contamination from vaginal shedding, other studies did not find any association between HIV transmission and DRM w7–11x. *Corresponding author. Tel.: q34-607-204147. E-mail address: ampagt@wanadoo.es (A. Garcia-Tejedor). It is known that uterine contractions increase the volume of materno-fetal blood transfusion w12x. A longer labor could therefore be associated with vertical HIV transmission, but most authors did not find a relationship between them w2,3,7,8,13,14x. The aim of this study was to determine the combined effect of DRM and labor duration on HIV transmission. 2. Patients and methods A retrospective cohort study was conducted at Maternal Hospital ‘La Fe’, Valencia, Spain,