Maternal Vitamin D Levels Tied to Growth in Term Infants

(HealthDay News) – Higher first-trimester maternal 25-hydroxyvitamin D (25[OH]D) levels are significantly linked to markers of growth in term infants, according to a study published in the Jan. 1 issue of the Journal of Clinical Endocrinology & Metabolism.

Alison D. Gernand, PhD, MPH, from the University of Pittsburgh Graduate School of Public Health, and colleagues analyzed measurements of maternal 25(OH)D in 2,146 mothers participating in the Collaborative Perinatal Project, an observational cohort conducted in 12 U.S. medical centers (1959–1965). 25(OH)D measurements were taken at a gestation of ≤26 weeks in women delivering singleton, term, live births.

The researchers found that, after adjustment for confounding variables, compared with mothers with 25(OH)D of <37.5nmol/liter, mothers with 25(OH)D of ≥37.5nmol/liter gave birth to newborns with 46g higher birth weights and 0.13cm larger head circumferences. Birth weight and head circumference increased with 25(OH)D up to 37.5nmol/liter and then plateaued. There was no correlation observed between 25(OH)D and ponderal index, placental weight, or the placental-to-fetal weight ratio. The risk of small-for-gestational-age was significantly reduced (adjusted odds ratio, 0.5) with maternal 25(OH)D of ≥37.5nmol/liter in the first trimester, but no association was seen in the second trimester.

“Our study is an important contribution to the epidemiology evidence that maternal vitamin D status, especially in early pregnancy, may contribute to both pathological and physiological fetal growth, but not placental growth, in term infants,” the authors write.

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