Low Vitamin D is Associated With Infections and Proinflammatory Cytokines During Pregnancy

Vitamin D is known to regulate innate and adaptive immune processes at the cellular level, but the role of vitamin D status on associated inflammatory processes across pregnancy is unclear. Our primary objective was to evaluate the relationships between serum biomarkers of inflammation (interleukin [IL]-6, IL-10, tumor necrosis factor [TNF]-α), acute-phase proteins (C-reactive protein and hepcidin) and vitamin D status, 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)₂D), measured across pregnancy and in the neonate at birth. A second objective was to identify associations between vitamin D status and clinically diagnosed infections. In this study, 158 racially and ethnically diverse pregnant adolescents were recruited from the Rochester Adolescent Maternity Program (RAMP) in Rochester, NY. Serum 1,25(OH)₂D was significantly lower in adolescents and neonates with IL-6 concentrations above the 75th percentile at delivery ( P = .04) and at birth ( P = .004), respectively. After adjusting for other potential covariates of inflammation, maternal serum 1,25(OH)₂D was significantly positively associated with TNF-α during pregnancy ( P = .02), but at delivery 1,25(OH)₂D and TNF-α were inversely associated with one another ( P = .02). Teens with 25(OH)D concentrations <30 ng/mL were more likely to test positive for candida ( P = .002) and bacterial vaginosis ( P = .02) during pregnancy. African Americans exhibited significantly lower TNF-α concentrations at both mid-gestation ( P = .009) and delivery ( P = .001) compared to the Caucasian adolescents. These results suggest that lower maternal vitamin D status may increase risk of infection across gestation.