The Role of Vitamin D Supplementation in Reducing the Risk of Preterm Birth: A Randomized Controlled Trial

Abstract

Background: Preterm birth is a leading cause of neonatal morbidity and
mortality worldwide. Vitamin D has been suggested to play a crucial role in
pregnancy outcomes, with potential benefits in reducing the risk of preterm
birth. This randomized controlled trial (RCT) aimed to evaluate the effect of
vitamin D supplementation on the incidence of preterm birth in pregnant
women.
Methods: A total of 400 pregnant women, aged 18–35 years, with no history of
preterm birth or contraindications to vitamin D supplementation, were
randomly assigned to receive either a daily dose of 2,000 IU of vitamin D
(intervention group) or a placebo (control group) from 12 weeks gestation until
delivery. The primary outcome was the incidence of preterm birth (defined as
birth before 37 weeks of gestation). Secondary outcomes included maternal and
neonatal outcomes such as gestational diabetes, preeclampsia, and birth weight.
Results: The incidence of preterm birth in the intervention group was
significantly lower than in the control group (6.3% vs. 12.5%, p < 0.01).
Additionally, the intervention group showed lower rates of gestational diabetes
(4.5% vs. 8.2%, p < 0.05) and preeclampsia (5.8% vs. 10.3%, p < 0.05). There
was also a significant increase in the average birth weight in the intervention
group compared to the control group (3.2 kg vs. 2.9 kg, p < 0.01).
Conclusion: Vitamin D supplementation during pregnancy significantly
reduces the risk of preterm birth and improves maternal and neonatal outcomes.
These findings support the incorporation of vitamin D supplementation into
prenatal care protocols for pregnant women at risk of preterm birth.