Longitudinal assessment of bacterial vaginosis prior to and during incident pregnancy: an observational study in Kenyan adolescent girls and young women

Objective To determine bacterial vaginosis (BV) status at multiple time points among adolescent girls and young women (AGYW) and assess the impact of pregnancy on their BV status.Design Longitudinal cohort study.Setting Thika, Kenya.Participants AGYW aged 16–20 years enrolled prior to first sex or reporting only a single lifetime partner.Main outcome measures The primary outcome was relative risk (RR) of BV during pregnancy compared with before pregnancy by analysing longitudinal trends in BV over time. BV risk was estimated using Poisson regression models.Results A total of 121 AGYW became pregnant in the parent cohort and had BV results before, during or after pregnancy. Point prevalence of BV was 11.0% at visits >12 months pre-pregnancy, 13.0% at 3–12 months pre-pregnancy, 22.1% at