What Difference Does Vitamin D Make?

Vitamin D levels during pregnancy appear not to affect child bone density

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Women might think that not having enough of certain vitamins during pregnancy can hurt their developing child. That may be true sometimes, but not always.

A recent study found that deficient or insufficient levels of vitamin D in pregnant women has no apparent effect on their children's bones later.

Among a large group of women, the children's bone scans showed no major differences regardless of whether the moms had high or low levels of vitamin D during pregnancy.

However, vitamin D deficiencies that might make a difference in other areas of a child's health were not investigated in this study.

"Take prenatal vitamins while pregnant."

The study, led by Debbie A. Lawlor, of the MRC Centre for Causal Analyses in Translational Epidemiology at the University of Bristol in the United Kingdom, aimed to understand whether a pregnant woman's vitamin D intake affected the bone health of her baby.

The researchers studied 3,960 women and their children. The mothers had their vitamin D blood concentrations measured while they were pregnant.

Women who had at least 50 nmol per liter were considered to have a sufficient amount of vitamin D in their bodies.

Insufficient vitamin D levels were defined as those between 27.5 nmol/L and 49.9 nmol/L. Deficient vitamin D levels were anything less than 27.5 nmol/L.

Then, when the children were 9 or 10 years old, they underwent a test called "dual-energy x-ray absorptiometry," or DXA. This test measures bone mineral density.

The researchers then compared the bone densities of the children to their mother's vitamin D levels during all three trimesters of pregnancy.

Overall, the majority of the women, 77 percent, had sufficient vitamin D levels. Only 6 percent had deficient levels, and 28 percent had insufficient levels.

However, the researchers found that the bone mineral densities of the children whose mothers had insufficient or deficient vitamin D levels did not appear affected by those low levels.

No differences were noted between the children of women with low vitamin D levels and the children of mothers with sufficient vitamin D levels.

The researchers also did not find any differences in the scans of the children during each trimester of the women, regardless of the women's vitamin D levels during pregnancy.

Therefore the researchers concluded that no association appears to exist between pregnant women's vitamin D levels and the bone mineral density of their children in late childhood.

The study was published March 19 in The Lancet. The research was funded by the UK Medical Research Council, the Wellcome Trust and the University of Bristol. The authors declared no conflicts of interest.

Reviewed by: 
Review Date: 
March 19, 2013
Last Updated:
March 21, 2013