Purpose: (1) To determine the prevalence of vitamin D deficiency in pregnant women. (2) To identify any correlations between maternal vitamin D levels and maternal and newborns' glucose and insulin levels.
Methods: This observational cohort study followed 149 healthy pregnant women visiting a hospital in Tehran, Iran in 2014 until the delivery of their term babies. Maternal serum vitamin D levels, and fasting blood glucose and insulin levels in both mothers and newborns were measured at delivery. Mothers' weight before pregnancy and right before delivery and babies' birth weight were measured.
Results: Of sample population, 27% had vitamin D deficiency, while 73% had insufficient vitamin D. No mother had sufficient vitamin D level. Maternal weight right before delivery negatively correlated with maternal serum vitamin D level (p = .04). Vitamin D deficiency is more prevalent in mothers who deliver a male infant (p = .03). Maternal serum vitamin D levels did not correlate with maternal or neonatal serum glucose or insulin levels or newborns' birth weight. Gestational age, maternal weight right before delivery, parity and maternal serum glucose predict infant's birth weight.
Conclusion: Vitamin D deficiency/insufficiency is prevalent among pregnant women. Factors causing this epidemic need investigation. Promoting consumption of vitamin D-fortified foods and supplements among pregnant women is suggested.
Keywords: Pregnancy; serum glucose and insulin; vitamin D deficiency; vitamin D insufficiency; vitamin D supplements.