Antiretroviral therapy and premature delivery in diagnosed HIV-infected women in the United Kingdom and Ireland.

Objective: To explore the association between antiretroviral therapy in pregnancy and premature delivery, birthweight, stillbirth and neonatal mortality, in pregnancies in HIV-infected women delivering between 1990 and 2005.

Design: Pregnancies in women with diagnosed HIV infection in the UK and Ireland are notified to the National Study of HIV in Pregnancy and Childhood (NSHPC) through a well-established surveillance scheme.

Results: The prematurity rate (< 37 weeks gestation) was higher in women on highly active antiretroviral therapy (HAART) (14.1%, 476/3384) than in women on mono/dual therapy (10.1%, 107/1061), even after adjusting for ethnicity, maternal age, clinical status and injecting drug use as the source of HIV acquisition [adjusted odds ratio (AOR) = 1.51, 95% confidence interval (CI), 1.19-1.93; P = 0.001]. Delivery at < 35 weeks was even more strongly associated with HAART (AOR = 2.34; 95% CI, 1.64-3.37; P < 0.001). The effect was the same whether or not HAART included a protease inhibitor. In comparison with exposure to mono/dual therapy, exposure to HAART was associated with lower birthweight standardized for gestational age (P < 0.001), and an increased risk of stillbirth (AOR = 2.27; 95% CI, 0.96-5.41; P = 0.063).

Conclusions: These findings, based on comprehensive population surveillance, demonstrate an increased risk of prematurity associated with HAART, and a possible association with other perinatal outcomes, including stillbirth and birthweight. Although the beneficial effects of antiretroviral therapy on mother-to-child transmission are indisputable, monitoring antiretroviral therapy in pregnancy remains a priority.