The relationship between maternal vitamin D status during third trimester of pregnancy and maternal and neonatal outcomes: A longitudinal study

Background: Vitamin D deficiency is a common nutritional concern and leads to several problems among some population groups. Objective: The aim of the current study was to evaluate the relationship between maternal vitamin D status and gestational weight gain, maternal biochemical parameters, mode of delivery, and infants’ growth indices at birth. Materials and Methods: A longitudinal study between March and June 2017 was carried on 82 mothers in Ahvaz. Blood samples of each mother were obtained at the mean of the third trimester to assay lipid indices (total cholesterol, triglycerides, lowdensity lipoprotein, and high-density lipoprotein cholesterol), fasting blood sugar, and 25-hydroxy vitamin D. Anthropometric assessment of newborns was recorded from neonatal health card at birth. Results: Mean maternal 25-hydroxy vitamin D level was 22.52 nmol/L; 7.33% of mothers had vitamin D deficiency, 76.6% had vitamin D insufficiency, and 15.9% were normal. The mean neonate birth weight, length, and head circumference of mothers who were on the third tercile of 25-hydroxy vitamin D serum level was significantly higher than those in the first tercile (p < 0.001, p = 0.004 and p < 0.001, respectively). Maternal vitamin D serum level had an adverse relationship with fasting blood sugar. Conclusion: Low levels of serum vitamin D may cause adverse pregnancy outcomes and delivery of infants with insufficient growth at birth.