Pregnancy in Women with HIV: Incidence and Outcomes over 19 Years in a Multi-Center Cohort in Spain

The aim of this study was to describe pregnancies among women with HIV (WWH) who became pregnant during follow-up in a Spanish multi-center cohort from 2004 to 2022 and analyze temporal trends. We included 2102 antiretroviral therapy (ART)-naïve WWH aged 18-50 years at enrolment, of which 358 (17.0%) became pregnant over 15,586 women-years of follow-up (509 pregnancies in total). The pregnancy incidence rate was 32.6 per 1000 women-years (95% confidence interval: 29.9, 35.6), which remained stable throughout the study. In 78.8% of the pregnancies, women were on ART at their last menstrual period, increasing from 49.2% in 2004 to 94.8% in 2022. In 43.4% of pregnancies, women received ART regimens not recommended during pregnancy. Treatment changes occurred in 43.1% of pregnancies, mainly in the first trimester (74.6%). Overall, 76.2% of pregnancies resulted in delivery, of which 48.2% were cesarean. Spontaneous and medical abortions occurred in 12.5% and 10.5% of pregnancies, respectively. In 92.0% of deliveries, women had an undetectable viral load (VL) at 36 weeks. The proportion of cesarean births among those with undetectable VL was 45.9%. Eighteen percent of newborns were preterm, and 11.5% had low birth weight. There was one neonatal death and one HIV perinatal transmission. In conclusion, most pregnancies occurred in women on ART with undetectable VLs at delivery. Despite this, there was a high proportion of cesarean births. Many women received ART regimens not recommended during pregnancy, with nearly half changing their treatment at least once.