Association of Bacterial Vaginosis with Vitamin D in Pregnancy: Secondary Analysis from the Kellogg Pregnancy Study.

 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.  Subjects with randomly assigned 400 versus 4,400 IU of daily cholecalciferol (vitamin D ) 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.  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 (  < 0.0001) and have lower 25(OH)D concentrations at 22 to 24 weeks' gestation (  = 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 (  = 0.001) and age (  = 0.03) were significant predictors of BV prevalence independently, 25(OH)D concentration (  = 0.81), gestational age (  = 0.06), and body mass index (  = 0.87) were not.  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.