The use of prenatal and postnatal vitamin D supplementation in mothers living in Bangladesh did not improve infant growth outcomes by 1 year of age, according to findings published in The New England Journal of Medicine.
“Vitamin D may influence fetal and postnatal growth through effects on calcium absorption, parathyroid hormone expression, phosphate metabolism, growth-plate function and regulation of the insulin-like growth factor axis,” Daniel E. Roth, MD, PhD, assistant professor in the department of pediatrics at the University of Toronto, and colleagues wrote. “Meta-analyses of observational studies and clinical trials have suggested that vitamin D may have a beneficial effect on fetal growth, but most previous trials have had methodologic limitations.”
Roth and colleagues conducted a randomized, double-blind, placebo-controlled trial that included mothers and infants in Bangladesh, a country where about 30% of infants born are small for gestational age, the reported. Furthermore, 36% of children aged younger than 5 years had stunted growth, and vitamin D deficiency among reproductive-aged women is common.
Mothers took weekly prenatal vitamin D supplements from 17 to 24 weeks’ gestation until birth in addition to postpartum vitamin D supplementation. Five cohorts were included, with groups receiving no supplementation (placebo), 4,200 IU of prenatal vitamin D, 16,800 IU of prenatal vitamin D, 28,000 IU of prenatal vitamin D or prenatal supplementation and 28,000 IU for 26 weeks postpartum. The researchers then examined infants’ length-for-age z scores once they reached 1 year of age and compared them with WHO’s child growth standards.
Of the 1,164 infants included in the trial, length-for-age z scores were similar for the placebo group (SD, –0.93 ± 1.05), 4,200 IU prenatal group (SD, –1.11 ± 1.12), 16,800 IU prenatal group (SD, –0.97 ± 0.97), 28,000 IU prenatal group (SD, –1.06 ± 1.07) and the prenatal and postnatal group (SD, –0.94 ± 1.00) when assessed at age 1 year.
Additionally, the researchers did not observe significant differences between the groups regarding the frequency of adverse events; however, women who received 28,000 IU of vitamin D had a higher rate of possible hypercalciuria.
“There were no apparent benefits of improved vitamin D status in the latter half of pregnancy on pregnancy, birth or infant outcomes, even without adjustment for multiplicity of testing for numerous secondary efficacy outcomes,” Roth and colleagues wrote. “Consistent with the findings of a recent meta-analysis, we did not find a reduction in the incidence of preterm births. The occurrence of four cases of rickets in the placebo group and the prenatal 4,200 group raised the possibility that doses of 16,800 IU per week or higher prenatally may prevent the development of early rickets, but there were too few cases to assess this question.” – by Katherine Bortz
Disclosures: The authors report no relevant financial disclosures.