Longitudinal Maternal Vitamin D Status during Pregnancy Is Associated with Neonatal Anthropometric Measures

Abstract

Findings on maternal 25-hydroxyvitamin D (25[OH]D) and neonatal anthropometry are inconsistent, and may at least be partly due to variations in gestational week (GW) of 25(OH)D measurement and the lack of longitudinal 25(OH)D measurements across gestation. The aim of the current study was to examine the associations of longitudinal measures of maternal 25(OH)D and neonatal anthropometry at birth. This study included 321 mother–offspring pairs enrolled in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies–Singletons. This study was a prospective cohort design without supplementation and without data on dietary supplementation. Nevertheless, measurement of plasma 25(OH)D reflects vitamin D from different sources, including supplementation. Maternal concentrations of total 25(OH)D were measured at 10–14, 15–26, 23–31, and 33–39 GW and categorized as <50 nmol/L, 50–75 nmol/L, and >75 nmol/L. Generalized linear models were used to examine associations of 25(OH)D at each time-point with neonate birthweight z-score, length, and sum of skinfolds at birth. At 10–14 GW, 16.8% and 49.2% of women had 25(OH)D <50 nmol/L and between 50–75 nmol/L, respectively. The association of maternal 25(OH)D with neonatal anthropometry differed by GW and women’s prepregnancy BMI (normal (<25.0 kg/m2), overweight/obese (25.0–44.9 kg/m2)). All analyses were stratified by prepregnancy BMI status. Among women with an overweight/obese BMI, 25(OH)D <50 nmol/L at 10–14 GW was associated with lower birthweight z-score (0.56; 95% CI: −0.99, −0.13) and length (−1.56 cm; 95% CI: −3.07, −0.06), and at 23–31 GW was associated with shorter length (−2.77 cm; 95% CI: −13.38, −4.98) and lower sum of skinfolds (−9.18 mm; 95% CI: −13.38, −4.98). Among women with a normal BMI, 25(OH)D <50 nmol/L at 10–14 GW was associated with lower sum of skinfolds (−2.64 mm; 95% CI: −5.03, −0.24), at 23–31 GW was associated with larger birthweight z-scores (0.64; 95% CI: 0.03, 1.25), and at 33-39 GW with both higher birthweight z-score (1.22; 95% CI: 0.71, 1.73) and longer length (1.94 cm; 95% CI: 0.37, 3.52). Maternal 25(OH)D status during pregnancy was associated with neonatal anthropometric measures, and the associations were specific to GW of 25(OH)D measurement and prepregnancy BMI.

Relationships between Total, Free and Bioavailable Vitamin D and Vitamin D Binding Protein in Early Pregnancy with Neonatal Outcomes: A Retrospective Cohort Study

“…We identified a novel relationship between birthweight and the biologically functional vitamin D component, free 25(OH)D. We also report a positive association between total 25(OH)D and birthweight, which is consistent with some studies showing that vitamin D deficiency in early pregnancy was associated with decreased birthweight [ 35 , 36 , 37 , 38 ], although others report no relationship [ 39 , 40 , 41 ]. Similarly, some clinical trials have shown improvements in birthweight and growth indices in women receiving vitamin D supplementation [ 42 , 43 ], while others have not [ 44 , 45 ].…”

“…Through the VDR, free 25(OH)D may directly regulate trophoblast differentiation and human chorionic gonadotrophin (hCG) production as well as stimulating the secretion of other hormones including estradiol, progesterone and placental lactogen. These hormones support uteroplacental blood flow and placental neovascularization, thereby facilitating fetal growth [ 38 ]. Vitamin D also influences the production and secretion of insulin, which is a growth-promoting hormone during fetal life, with direct and indirect effects on adipogenesis and stimulation of insulin-like growth factors and their binding proteins, respectively [ 48 , 49 , 50 ].…”

Early Pregnancy Vitamin D Binding Protein Is Independently Associated with the Development of Gestational Diabetes: A Retrospective Cohort Study

“…Nevertheless, the length of gestation was significantly associated with total 25(OH)D as well as with free and bioavailable 25(OH)D, although the latter were attenuated after accounting for ethnicity in the multivariable models. The positive association between the length of gestation and total 25(OH)D has been reported previously [58][59][60][61], indicating that higher levels of total 25(OH)D may indeed be related to delivery at a later gestation. However, the relationships between free and bioavailable 25(OH)D with length of gestation await further study.…”

Importance of vitamin D supplementation in pregnancy-review

“…Vitamin D has effect on type II pneumocytes and surfactant production also which has an impact on lung growth and development. 42,43…”