Third-Trimester Maternal and Neonatal Cord Blood Vitamin D3 Levels in Urban South India: An Observational Cross-Sectional Study.

INTRODUCTION: Vitamin D plays a crucial role in bone health, immune function, and metabolic regulation. Despite ample sunlight, vitamin D deficiency (VDD) remains prevalent in India, particularly among pregnant women and neonates. This study investigates the correlation between maternal serum and neonatal cord blood vitamin D3 levels during the third trimester and at birth, assessing how maternal vitamin D status influences neonatal outcomes. OBJECTIVE: This research aims to study the correlation between maternal serum vitamin D3 levels in the third trimester and neonatal cord blood vitamin D3 levels. METHODS: This observational cross-sectional study was conducted at a tertiary care center from August 2022 to February 2024. The study included 58 pregnant women aged 18-45 and their neonates. Maternal serum samples were collected during the third trimester, and cord blood samples were obtained at delivery. Data were analyzed using Statistical Package for the Social Sciences (SPSS) 23.0 (IBM Corp., Armonk, NY), with categorical variables expressed as frequencies/percentages and numerical data as mean ± standard deviation (SD). Pearson's correlation assessed the maternal-neonatal vitamin D3 relationship. RESULTS: A strong positive correlation was found between maternal and neonatal vitamin D3 levels (Pearson's coefficient: 0.74; p < 0.001; 95% confidence interval {CI}: 0.62-0.83). Among neonates born to vitamin D-deficient mothers, 55.6% were also deficient. No significant associations were observed between maternal vitamin D3 levels and demographic factors (age, religion, education, and socioeconomic status {SES}; p > 0.05) or neonatal outcomes (birth weight, length, and head circumference). Limitations include an exclusive focus on urban residents and potential recall bias in self-reported supplementation data. CONCLUSION: Maternal vitamin D levels strongly correlate with neonatal levels, emphasizing the need for routine prenatal screening and targeted supplementation to address deficiencies and improve maternal and neonatal health outcomes.