Vitamin D during pregnancy shows no benefit for infant growth

Vitamin D deficiency and impaired linear growth of children – a condition called stunting – are both problems of grave magnitude in Bangladesh. One in three children is stunted in Bangladesh while 40 percent of the population suffers from deficiency of vitamin D, which is also believed to cause stunting.

Pregnant women should be advised that sunlight is the most important source of vitamin D: WHO. Photo: GMB Akash / icddr,b

This led to a large trial of vitamin D supplementation during pregnancy and lactation to see if there is an impact on child linear growth.

The results of the trial, published recently in the prestigious journal New England Journal of Medicine show that supplementing pregnant and lactating women with vitamin D does not improve child growth.

The World Health Organization (WHO) currently does not recommend Vitamin D supplementation for pregnant women for child growth outcome. Mothers who are already deficient, however, can take supplimentary vitamin D as prescribed by a medical practioner.

The trial on over 1300 pregnant women was done in Dhaka by investigators from icddr,b and Hospital for Sick Children, Toronto, in collaboration with the Maternal and Child Health Training Institute of the Government of Bangladesh, with support from the Bill and Melinda Gates Foundation, USA.

The five-year long trial administered vitamin D in mid-pregnancy in three doses of 28,000 international units, 16,800 IU and 4,200 IU per week for 26 weeks along with 500 mg of calcium, 66 mg of iron and 350 mcg of folic acid every day. Another group of women was not given vitamin D during the same period.

“When children were examined at age 1 year, no difference in their length for age was observed regardless of maternal intake of vitamin D, which suggests that supplementation with vitamin D during pregnancy has no impact on child growth,” observes Mr Abdullah Al Mahmud, senior author of the article and project coordinator with icddr,b.

All groups had similar rates of hospitalisation and infant death, and there were no cases of adverse consequences from maternal and/or infant hypercalcemia (excess calcium in blood).

“The results of the study further highlight the multifactorial nature of childhood stunting, the exact causes and remedy of which are still elusive”, says Dr Tahmeed Ahmed, senior director of nutrition and clinical services division and senior scientist as well as a co-author of the article.

He also adds that there is a plethora of ongoing research at icddr,b on the causes and solutions for impaired growth of children as well as deficiency of vitamin D.