Paternal race and bacterial vaginosis during the first trimester of pregnancy.

Objective: The purpose of this study was to determine the joint effects of maternal and paternal race on risk of bacterial vaginosis (BV) during the first trimester.
Study Design: In this cohort of black women and white women with singleton gestation at <13 weeks (n = 325), BV was diagnosed by vaginal pH and Gram stain.
Results: BV was less common among white women than black women. Paternal race modified the effect of maternal race on BV risk. BV risk was 2-fold greater among both white female-black male partners and black female-white male partners. BV risk was also 2-fold greater among black female-black male partners. Black race among both partners confers no additional risk than with 1 black partner.
Conclusion: Paternal black race is an independent risk factor for BV during pregnancy and is as important a risk factor as maternal race. Studies of BV and adverse pregnancy outcomes should consider paternal race.