title: Antiretroviral therapy in pregnancy: balancing the risk of preterm delivery with prevention of mother-to-child HIV transmission.
abstract: 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.
authors: Medical Research Council Centre of Epidemiology for Child Health, UCL Institute of Child Health, University College London, UK. c.townsend@ich.ucl.ac.uk
authors: Claire L
authors: CL
authors: Townsend
authors: Pat A
authors: PA
authors: Tookey
authors: Marie-Louise
authors: ML
authors: Newell
authors: Mario
authors: M
authors: Cortina-Borja
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000635:transmission / Q000821:virology; D015497:HIV-1 / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control* / Q000706:statistics & numerical data; D007494:Ireland / Q000453:epidemiology; D009010:Monte Carlo Method; D011159:Population Surveillance; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology; D047928:Premature Birth / Q000453:epidemiology* / Q000517:prevention & control; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use; D018570:Risk Assessment; D006113:United Kingdom / Q000453:epidemiology; D015215:Zidovudine / Q000627:therapeutic use
chemical_list: D019380:Anti-HIV Agents; D018894:Reverse Transcriptase Inhibitors; D015215:Zidovudine