Vaginal washing behaviour and fecundability among Kenyan women in a prospective preconception cohort

Intravaginal washing, practised by a significant proportion of women globally, is associated with acquisition of human immunodeficiency virus (HIV), sexually transmitted infections and bacterial vaginosis (BV). A single prior study among women in the United States found that vaginal washing was associated with lower fecundability.

To examine the association between vaginal washing and fecundability among Kenyan women.

HIV-negative Kenyan women who were trying to conceive and reported no history of infertility care-seeking were followed prospectively for incident pregnancy for up to six months. At monthly visits, participants reported the first day of last menstrual period, sexual behaviour, vaginal washing behaviour, underwent pregnancy testing and provided vaginal swabs for detection of BV by Gram stain (Nugent score ≥7). Discrete time proportional probability models were used to estimate fecundability ratio (FR) and 95% confidence interval (CI) comparing menstrual cycles when women reported vaginal washing to menstrual cycles when no vaginal washing was reported.

Four hundred and fifty-eight women contributed 1,376 menstrual cycles and 255 pregnancies. At enrolment, a third (35.2%, 161 of 458) of participants reported vaginal washing with the majority using water only (73.9%, 119 of 161). After adjustment for age, frequency of unprotected intercourse and study site, vaginal washing in the prior four weeks was associated with a 29% lower fecundability (adjusted FR [aFR] 0.71, 95% CI 0.53, 0.94), which did not change after further adjustment for BV at the visit prior to each pregnancy test (aFR 0.71, 95% CI 0.54, 0.95).

Periconceptual vaginal washing may reduce fecundability. Potential mechanisms include vaginal washing-associated changes in the vaginal microbiota, inflammation, disruption of cervical mucus and effects on sperm function. Vaginal washing has no known health benefits, and cessation may improve women's likelihood of conceiving.