Low rates of mother-to-child transmission of HIV-1 and risk factors for infection in Spain: 2000-2007.

BACKGROUND: The objective of the study was to describe temporal patterns in the management of HIV-1 infected women and their newborns and the changes over time in the mother-to-child transmission (MTCT) rates and risk factors. METHODS: A multicenter prospective observational study was performed in Madrid, Spain, from 2000 to 2007. Cohort period 1 (CP1) included births in 2000-2003 and cohort period 2 (CP2) included births in 2004-2007. RESULTS: Of the 803 HIV-infected women and their infants, 427 were in the CP1 and 376 in CP2. Almost all CP2 women received highly active antiretroviral therapy. More women in CP2 received antiretroviral treatment for ≥16 weeks during pregnancy (72.0% in CP1 vs. 84.8% in CP2; P < 0.001). Overall, no differences in trends in mode of delivery were observed. The proportion of women with vaginal deliveries who had undetectable viral loads increased from 31.1% in CP1 to 42.7% in CP2 (P = 0.02). Thirteen children (1.6%, 95% confidence interval: 0.68-2.55) were HIV-1 infected by MTCT. No changes in the rates of infection were observed over time. All the cases of MTCT occurred when antiretroviral treatment was not given or was given for <16 weeks during pregnancy. CONCLUSIONS: Low MTCT rates were observed over time. Lack of timely provision of antiretroviral drugs was the main limitation to develop all preventive interventions available nowadays. Nonsustained control of viral load could be associated with residual transmission.