Vitamin D levels in pregnancies and neonatal outcomes

Objective: We aimed to evaluate the differences in obstetrics and neonatal outcomes, such as mode of delivery, gestational diabetes mellitus, preeclampsia, and infant birth weight between pregnancies with normal and insufficient vitamin D levels. Methods: The study was designed as a retrospective study. One hundred and seventy-nine pregnant women who were followed up at our clinic and whose vitamin D levels were evaluated in each trimester were included. All patients were administered 1200 IU/day beginning from the 12 weeks of gestation in accordance with the national guidelines. Vitamin D levels above 20 ng/ml were defined as sufficient, and those below 20 ng/ml were defined as insufficient. Results: The median vitamin D level in the third trimester was significantly higher than that in the first and second trimesters (p<0.001). There was a moderate positive correlation between vitamin D levels in infant cord blood at the time of birth and vitamin D levels in the third trimester (p<0.001, R=0.496). Birth weights of the patients with insufficient vitamin D levels in the first trimester but with sufficient neonatal cord blood levels as a result of treatment were significantly higher compared to those in patients with insufficient cord blood vitamin D levels (3327 g vs. 3133 g, p=0.030). Conclusion: This study observed that neonatal cord blood vitamin D level is a better indicator than antenatal vitamin D levels. Regardless of first-trimester vitamin D levels, infant birth weights were significantly higher in the group with sufficient neonatal cord blood levels.