BACKGROUND: Mitochondrial toxicity was described in infants exposed to long-term antiretroviral regimens containing nucleoside analogues for the prevention of mother-to-child transmission of HIV. We measured the serum lactate levels in children born to HIV-1 infected African women receiving short-term antiretroviral prevention of mother-to-child transmission of HIV regimens. METHODS: A prospective study was conducted in women-child pairs from the third trimester of pregnancy to 3 months of life. The exposed group was formed by children exposed in utero to nucleoside analog antiretroviral regimens, zidovudine or zidovudine + lamivudine from 32 to 36 weeks of amenorrhea until delivery. All of these women received nevirapine single dose at the beginning of labor. The children received zidovudine during the first 7 days of life and a nevirapine single dose at day 3. The control group was formed by infants born to HIV-1-infected women who had received nevirapine single dose only and who were not exposed to nucleoside analog antiretroviral regimens. Serum lactate levels were measured at 4, 6, and 12 weeks of life by Cobas Integra 400. RESULTS: A total of 836 blood samples from 338 infants was collected (262 exposed and 76 controls). Median lactacidemia was 1.8 mmol/L (interquartile range: 1.2-2.7 mmol/L). Overall serum lactate levels > or = 2.5 mmol/L, defining hyperlactatemia, were observed in 39 of the 292 infants who had > or = 2 serum lactate measurements. The 3-month period prevalence of hyperlactatemia did not differ between the exposed group and the control group. All of the serum lactate levels returned to normal values in all of the subsequent samples. No case of symptomatic hyperlactatemia was detected during the study period. CONCLUSIONS: Increased lactate levels were identified equally in infants whose mother received short-term nucleoside analogs or nevirapine single dose for prevention of mother-to-child transmission of HIV. Although not rare, hyperlactatemia was not related to short-term exposure to nucleoside analog antiretroviral regimens.