Are HIV‐related factors associated with pre‐term delivery in a UK inner city setting?

Abstract

Purpose: In the UK the accepted standards for the management of HIV-positive pregnant women are the British HIV Association Guidelines [1]. The guidelines were updated in 2012 and make reference to conflicting evidence regarding the risk of premature birth; some studies suggest an increased risk of preterm delivery (PTD) in women treated with protease inhibitors (PIs) but others do not. Several of these studies have been conducted in developing countries and not in a setting analogous to UK healthcare. The aim of this study was to examine data from HIV-positive pregnant women attending a large UK teaching hospital, comparing the rates of PTD in women on PI-based regimes to those on non-PI based regimes. In addition, known and possible confounding risk factors for prematurity were considered. Methods: We analysed retrospective data from the files of HIVpositive women attending a UK maternity center with specialist HIV care between 2003 and 2012. Inclusion criteria were women who delivered live-born infant(s) beyond 24 weeks gestation, and who were taking anti-retroviral treatment at some point during the first 37 weeks of their pregnancy. Preterm delivery was defined as delivery at less than 37 weeks. Multi-variable logistic regression adjusted for repeated measures was used to compare the rates of PTD in women on non-PI-based regimes with those on PI-based regimes; adjusting for possible covariates, including the percentage increase in CD4 count during pregnancy, the timing of HAART initiation, and concurrent genital tract infections. Results: A total of 208 pregnancies in 157 women were included in the study. The overall prematurity rate was 11.1% (PI=11.1%, non- PI=10.8%), of which 5.8% were before 34 weeks. Analysis of the data demonstrated no statistically significant increased risk between PI and non-PI based regimes, which persisted following adjustments for known and possible confounding factors. Conclusions: In this study 11.1% of HIV-positive women experienced PTD; in the general UK population 7.5% of pregnancies end in PTD [2]. The inclusion of a PI in the mother's HIV drug regime was not associated with an increased risk for PTD. An association between PTD and CD4 count increase in pregnancy of borderline significance was noted; p=0.053. This is particularly relevant for women commencing HAART during pregnancy in whom, although over 1.5 times as likely to have PTD as those on treatment at conception, this was not statistically significant.