Background For women with HIV in resource-rich countries antenatal practice has shifted away from use of zidovudine monotherapy towards routine use of highly active antiretroviral therapy (HAART), in order to suppress plasma viraemia and minimise mother-to-child transmission. European and UK studies have consistently demonstrated increased preterm delivery (PTD) rates in women taking HAART but have not investigated the factors leading to PTD.

Methods The authors performed a retrospective review of obstetric and medical data for all HIV positive women delivering at a London teaching hospital between 2002 and 2009 (n=204) in order to identify gestational age at delivery in women taking HAART. Preterm deliveries were classified as (1) prelabour premature rupture of membranes (PPROM), (2) spontaneous labour or (3) medically indicated. Information was obtained from a pre-existing database and maternity notes.

Results 178 of the study cohort were taking HAART, of whom 174 were Black African or Afro-Caribbean. Mean age was 33 years (range 18–45). There was one mother-to-child transmission. Excluding multiple pregnancies (n=2), 31 women (17.4%) delivered <37 weeks, of whom 14 (7.9%) delivered <34 weeks. Only one of those delivering preterm reported illegal drug use. PTD was attributed to PPROM in 12 (38.7%), spontaneous labour in 10 (32.3%) and was medically indicated in 9 (29.0%).There was no significant association between PTD and timing of HAART initiation, or with class of antiretroviral used.

Conclusions The high PTD rate for women taking HAART in this cohort (17.4%) was multi-factorial but most commonly attributed to PPROM. A case-controlled study is warranted.