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Do vitamin D levels in mothers have an effect on their child’s bone health?

March 21, 2013

According to a new study from the UK there is no evidence that women’s blood vitamin D concentrations during pregnancy are associated with the offspring’s total body or spinal bone mineral concentrations. However, experts recommend vitamin D supplementation during pregnancy to support both maternal and fetal bone health.

The observational study measured 25-hydroxyvitamin D blood levels of 3960 pregnant women in all tri-mesters (1). At an average age of nine years and 11 months, their children’s bone mineral content (BMC) was assessed by dual-energy X-ray absorptiometry. The study results showed no significant association between the mothers’ vitamin D levels and their children’s BMC. The vitamin D levels of the women were on average lowest during their first trimester, and then increased as the pregnancy progressed; as expected, levels were higher when measured during summer months and lower when measured during winter months. Although non-white mothers and those who smoked during pregnancy tended to have lower vitamin D levels overall, this appeared to have no effect on their children’s bone health.

The researchers commented that health guidelines may be overstating the importance of vitamin D supplementation in pregnancy, saying there is no strong evidence that pregnant women should receive vitamin D supplementation to prevent low BMC in their offspring. However, there could be other possible beneficial effects of vitamin D in pregnant women, they said.

Previous studies on maternal vitamin D status and offspring’s bone health have produced inconsistent results. Experts recommend routine vitamin D supplementataion for pregnant women who are at increased risk of deficiency. Currently, the American College of Obstetrics and Gynecology and the Institute of Medicine recommend 600 IU of daily vitamin D supplementation during pregnancy to support maternal and fetal bone metabolism (2). Vitamin D supplementation has been suggested to prevent pre-eclampsia, gestational diabetes, impaired glucose tolerance, gestational hypertension and even death among mothers, and preterm birth, infection or death of newborns.

References

  1. Lawlor D. A. et al. Association of maternal vitamin D status during pregnancy with bone-mineral content in offspring: a prospective cohort study. The Lancet. Published online March 2013.
  2. American College of Obstetrics and Gynecology. Vitamin D - Screening and Supplementation During Pregnancy. Committee Opinion. No. 495; July 2011.