Objective Bacterial vaginosis (BV) is associated with vitamin D deficiency and poor pregnancy outcomes. We studied a nested cohort from a randomized controlled trial to investigate the association between BV and vitamin D concentration in pregnancy. Study Design Subjects with randomly assigned 400 versus 4,400 IU of daily cholecalciferol (vitamin D 3 ) had vaginal swabs collected for Gram staining and Nugent score calculation, as well as plasma 25-hydroxyvitamin D (25(OH)D) measurement at three pregnancy time points. Results Fifty-two (21.2%) of the 245 women included in the analysis were diagnosed with BV at study entry. Women with BV were also more likely to be African American ( p < 0.0001) and have lower 25(OH)D concentrations at 22 to 24 weeks' gestation ( p = 0.03). There were no differences in pregnancy outcomes of interest within this group compared with the remaining study subjects. In mixed regression modeling, while race ( p = 0.001) and age ( p = 0.03) were significant predictors of BV prevalence independently, 25(OH)D concentration ( p = 0.81), gestational age ( p = 0.06), and body mass index ( p = 0.87) were not. Conclusion Neither vitamin D deficiency in early pregnancy nor supplementation decreased BV incidence during pregnancy. Pregnancy outcomes (preterm birth and hypertensive disorders of pregnancy) were similar among women with and without BV.
Keywords: Gram stain; bacterial vaginosis; pregnancy; vitamin D supplementation.