Antiretroviral therapy in pregnancy: balancing the risk of preterm delivery with prevention of mother-to-child HIV transmission.

BACKGROUND

Highly active antiretroviral therapy (HAART) for pregnant HIV-positive women reduces the risk of mother-to-child transmission, but is associated with an increased risk of preterm delivery (<37 weeks gestation). We aimed to quantify the incremental risk-benefit ratio for HAART compared with zidovudine monotherapy with respect to these outcomes.

METHODS

Two-stage Monte Carlo simulation methods were used to estimate the risk-benefit ratio for HAART in pregnancy. Estimates of mother-to-child transmission and preterm delivery rates were obtained from UK and Ireland surveillance data collected through the National Study of HIV in Pregnancy and Childhood.

RESULTS

At a population level, HAART was associated with a more than sevenfold reduction in mother-to-child transmission compared with zidovudine monotherapy (adjusted odds ratio [AOR] 0.13, 95% confidence interval [CI] 0.06-0.27), but with a 1.4-fold increased odds of preterm delivery (AOR 1.43, 95% CI 1.10-1.86) and twofold increased odds of severe preterm delivery (<32 weeks; AOR 2.06, 95% CI 1.09-3.88). The incremental risk-benefit ratio for HAART in pregnancy compared with monotherapy was 0.63 (95% simulation interval 0.06-1.96) additional preterm births and 0.23 (95% simulation interval -0.02-0.88) severe preterm births for each infection prevented.

CONCLUSIONS

It is estimated that for every 100 HIV transmissions prevented through the use of HAART (rather than monotherapy), 63 additional preterm deliveries would occur, including 23 at <32 weeks gestation. Interpretation of these ratios is context-dependent and requires additional information about morbidity, mortality and costs associated with the outcomes.