Genitourinary pathogens and preterm birth

Purpose of review The aim is to describe and quantify the association between genitourinary tract infections and preterm birth. Recent findings Recent studies confirm the importance of identifying and treating both asymptomatic and symptomatic bacteriuria in pregnancy, which is reflected in current antenatal screening guidelines. These guidelines do not recommend routine screening for other asymptomatic lower genital infections (bacterial vaginosis, trichomonas and gonorrhoea) reflecting inconsistent study results, which may reflect differences in study design, size, diagnostics and the timing of screening in pregnancy. Screening for group B Streptococcus (GBS) late in pregnancy is recognized to reduce neonatal disease, but there is a striking lack of robust studies, specifically randomized controlled trials (RCTs), considering the effect of GBS screening earlier in pregnancy on adverse pregnancy outcomes. Summary The potential for screening and treatment of genitourinary tract infections in pregnancy to reduce preterm birth rates has been demonstrated in some RCTs. Current guidelines do not reflect these data because of inconsistencies across the body of evidence. There is a need for robust RCTs to confirm or refute earlier data, to inform the optimal timing for screening in pregnancy and to better quantify the contribution of individual infections to the burden of preterm birth.