Maternal Vitamin D Status Linked to Preterm Delivery

THURSDAY, Sept. 24, 2026 (HealthDay News) — Women who deliver preterm have lower vitamin D concentrations than women who deliver at term, according to a study recently published online in the Journal of Perinatology.

Anjali G. Borsum, from the University of South Carolina in Charleston, and colleagues investigated the association between women’s vitamin D status (as measured by 25-hydroxyvitamin D concentration [25(OH)D]) and gestational age at delivery. The analysis included data from 15,506 women delivering from January 2016 to March 2024.

The researchers found that women delivering before 37 weeks (1,652 deliveries) had lower 25(OH)D concentrations than those delivering at 37 weeks or later (13,451 deliveries; 31.3 ± 17.8 ng/mL versus 34.8 ± 17.3 ng/mL). Among women delivering before 32 weeks (385 deliveries; 25[OH]D concentrations, 26.2 ± 14.9 ng/mL), this difference was even more pronounced (mean difference versus term babies, –8.56 ng/mL).

“Although these findings do not establish causality, they contribute real-world evidence from a large, diverse U.S. population to a growing literature suggesting that maternal vitamin D status may be relevant to pregnancy outcomes,” the authors write. “Further prospective studies and randomized trials are needed to determine whether optimizing vitamin D status during pregnancy can meaningfully reduce the risk of preterm birth and to identify populations most likely to benefit from targeted interventions.”

Abstract/Full Text