Abstract:The toxic potential of nevirapine in pregnant women with CD4 count over 250 cells mmand the unsatisfactory efficacy of nelfinavir in patients with baseline Viral Load (VL) over 100,000 copies mL −1 has prompted the use of Lopinavir/ritonavir (LPV/r) in selected situations. This study aims to assess safety of LPV/r in pregnancy. Medical records from pregnant women receiving LPV/r were retrospectively reviewed. Charts corresponding to twin pregnancy, hypertension and having a lack of data supporting a reliable estimate of Gestational Age (GA) at delivery were excluded. Low Birth Weight (LBW) was defined as less than 2500 g. Pre-Term Delivery (PD), defined as GA at delivery less than 259 days, was estimated using date of Last Menstruation Period (LMP) and obstetrical ultrasound. A total of 64 women were analyzed. LPV/r was used in 46.9% due to virologic failure with other Protease Inhibitors (PIs). LPV/r was used for a mean of 108.8 days. Baseline median CD4+ cell count and HIV-1 RNA were 287 mm −3 and 31,100 copies mL, respectively and 345 mmand less than 400 copies mL −1 at delivery. HIV-1 was not transmitted to any newborn. LBW was observed in 13 (20.3%) and PD in 16 (25%) newborns. Time on LPV/r during pregnancy, maternal age, baseline CD4+ cell count and HIV-1 RNA, GA at initiation of LPV/r, reason for prescribing LPV/r and type of delivery were not associated with PD. Frequencies of LBW and PD were, respectively, 20.3 and 25%. Neither the magnitude nor the timing in pregnancy of LPV/r use was associated with PD.