Abstract
OBJECTIVE: This study aimed to evaluate the relationship between maternal serum 25-hydroxyvitamin D [25(OH)D] levels and the likelihood of vaginal delivery. MATERIALS AND METHODS: This observational case-control study was conducted with a total of 298 women, comprising a case group of those who were unable to deliver vaginally and underwent emergency cesarean section (n = 49), and a control group of those who delivered vaginally (n = 249). The study data were collected using a questionnaire developed in line with the relevant literature. To explore the effects of independent variables on the dependent variable, both univariate and multivariate logistic regression analyses were performed. RESULTS: According to the findings of our study, higher serum 25(OH)D levels were significantly associated with a reduced risk of cesarean delivery (β = -0.369, p = 0.001). Specifically, each 1 ng/mL increase in serum 25(OH)D levels reduces the risk of cesarean delivery by approximately 30.8% [Exp(β) = 0.692, 95% CI = 0.611-0.783]. On the other hand, a high body mass index (BMI) pre-pregnancy and at the time of delivery, excessive gestational weight gain, and the presence of chronic diseases were associated with a higher risk of cesarean delivery (p < 0.05). In addition, giving birth at a later gestational week was found to be associated with a higher rate of vaginal delivery (p < 0.05). No significant associations were found between the mode of delivery and maternal age, total number of pregnancies, previous vaginal delivery, pre-pregnancy family planning method, neonatal birth weight, the total number of non-stress tests (NSTs) performed during pregnancy, or the number of antenatal physician visits (p > 0.05). CONCLUSION: Higher serum vitamin D levels were associated with an increased likelihood of vaginal delivery. In this context, optimizing vitamin D status through sunlight exposure, nutrition, or supplementation may represent an important step in protecting maternal and neonatal health.