Every day, more than 1,000 babies are born prematurely across North America. But new research suggests that many of those early deliveries could be avoided by boosting pregnant women’s vitamin D levels.

A new study from South Carolina involving more than 1,000 pregnant women found that up to 90 per cent of them had a vitamin D deficiency. The problem was especially pronounced among African-American and Hispanic women, researchers found.

The lower a woman’s blood level of vitamin D was, the higher the risk of delivering a premature baby, the study found.

Researchers then offered free vitamin D supplements to women who had low levels. Women who boosted their vitamin D blood levels to at least 40 nanograms per millilitre had a 62 per cent lower rate of premature delivery, the study found. 

“Those women who were able to raise their vitamin D levels from early pregnancy, when they were deficient…to greater than 40 nanograms per millilitre by later pregnancy, had substantially lower rates of pre-term delivery,” said Dr. Roger Newman, a co-author of the study and the director of Women’s Health Research at the Medical University of South Carolina.

“I think it’s hugely significant,” he told CTV News.

“Vitamin D is inexpensive. Vitamin D is extremely-well tolerated,” he said, adding that in the study, researchers didn’t find “a single complication” related to taking the supplement.

“The potential is huge as a low-cost, safe intervention with the potential to reduce the risk of prematurity and prematurity-related complications,” Dr. Newman said.

Canadian experts say more research needs to be done to confirm the results of the study, but they find it intriguing.

Dr. William D.  Fraser, an obstetrician-gynecologist and clinician-researcher at Universite de Sherbrooke, said vitamin D is found in a variety of foods and easily administered via inexpensive supplements, “so it’s relatively accessible to the population.”

Previous studies have shown that women of colour seem to be particularly vulnerable to low vitamin D levels during pregnancy.

Dr. Fraser said obstetricians don’t routinely check their pregnant patients’ vitamin D levels, but women who are concerned can ask their doctor to have their blood levels tested. Those who are found to have low vitamin D levels can request a supplement prescription.

“(Vitamin D) is beneficial to a woman just for maintaining her own health,” Dr. Fraser said, adding that he hopes more research into vitamin D and pregnancy will be funded in the next few years. 

The Canadian Paediatric Society also updated its guidelines on vitamin D supplementation for mothers and infants earlier this year.

With a report from CTV’s medical affairs specialist Avis Favaro and producer Elizabeth St. Philip