Associations of free, bioavailable and total 25-hydroxyvitamin D with neonatal birth anthropometry and calcium homoeostasis in mother-child pairs in a sunny Mediterranean region

Sufficient vitamin D status is crucial for successful pregnancy and fetal development. The assessment of 25-hydroxyvitamin D (25(OH)D) concentrations is commonly used to evaluate vitamin D status. Our objective was to examine the interrelated biodynamics of maternal and neonatal total, free and bioavailable 25(OH)D in maternal-neonatal dyads at birth and their associations with homeostasis and neonatal birth anthropometry. We analysed a cohort of seventy full-term mother-child pairs. We found positive associations between all neonatal measures of vitamin D status. Maternal forms exhibited a similar pattern of association, except for the bioavailable maternal form. In multivariate analysis, both total and free maternal 25(OH)D concentrations were correlated with all neonatal forms (neonatal total 25(OH)D: 1 center dot 29 (95 % CI, 1 center dot 12, 1 center dot 46) for maternal total 25(OH)D, 10 center dot 89 (8 center dot 16, 13 center dot 63) for maternal free 25(OH)D), (neonatal free 25(OH)D: 0 center dot 15 for maternal total 25(OH)D, 1 center dot 28 (95 % CI, 0 center dot 89, 1 center dot 68) for maternal free 25(OH)D) and (0 center dot 13 (95 % CI, 0 center dot 10, 0 center dot 16), 1 center dot 06 (95 % CI, 0 center dot 68, 1 center dot 43) for maternal free 25(OH)D), respectively, with the exclusion of the bioavailable maternal form. We observed no significant interactions within or between groups regarding maternal and neonatal vitamin D parameters and maternal calcium and parathyroid hormone concentrations, and neonatal birth anthropometry. Our study indicates that bioavailable maternal and neonatal 25(OH)D have no significant effects on vitamin D equilibrium, Ca homeostasis and neonatal anthropometry at birth. However, we observed an interaction between maternal and neonatal total and free 25(OH)D concentrations at the maternal-neonatal interface, with no associations observed with other calciotropic or anthropometric outcomes.

Automated summary

Sufficient vitamin D status is crucial for successful pregnancy and fetal development. This study found positive associations between maternal and neonatal vitamin D status, with the exception of bioavailable maternal form. There were no significant interactions between maternal and neonatal vitamin D parameters and other calciotropic or anthropometric outcomes.