5 Key Takeaways

• 1

  Lower maternal vitamin D concentrations may be associated with earlier gestational age at delivery.

• 2

  The study included 15,506 women who delivered at the Medical University of South Carolina from 2016 to 2024.

• 3

  Mean maternal 25(OH)D concentration was 34.8 ng/mL for term deliveries, compared to 31.3 ng/mL for deliveries at 32 to 36 weeks.

• 4

  Overall, 45% of women had at least one 25(OH)D concentration below 30 ng/mL, with significant variation across racial and ethnic groups.

• 5

  The study's retrospective design limits causal inference, and further prospective studies are needed to clarify the findings.