Vitamin D supplements during pregnancy reduced the risk of premature births at an urban medical center by 60 percent, a study reports.
A key implication of the research is that fewer premature births translate into fewer disorders such as cerebral palsy that are associated with preterm deliveries.
Researchers featured the findings in a study in the journal PLOS ONE titled “Maternal 25(OH)D concentrations ≥40 ng/mL associated with 60% lower preterm birth risk among general obstetrical patients at an urban medical center.”
Between 5 and 18 percent of births worldwide are preterm. Children born prematurely are not only more prone to developing neurodevelopmental problems, but also to experience birth complications that can lead to death. Preterm births can increase the risk of a newborn developing cerebral palsy, autism, and other neurological conditions, studies have shown.
Since preterm births are “the leading cause of neonatal [newborns’] death and multiple short- and long-term health problems, it is critical to identify” risk factors during pregnancy that could be modified to reduce premature births, the researchers wrote.
Previous studies have shown that higher levels of vitamin D in the blood of pregnant women — whether from food, supplements, or exposure to sunlight — reduced the risk of a premature birth. Based on these findings, the Medical University of South Carolina in Charleston revised its guidelines for pregnancy follow-up to include vitamin D testing and, where needed, the prescribing of supplements.
To confirm that the supplements can reduce the risk of preterm births, researchers looked at patient records at their facility after the new guidelines went into effect.
The study covered 1,064 women who gave birth there from September 2015 to December 2016. Blood tests to measure vitamin D were performed while the women were pregnant. Free supplements were offered to those whose vitamin D fell below a certain level.
Statistical analysis showed that women with levels higher than the cut-off were at 62 percent less risk of a premature birth than those with lower concentrations.
“We found a clear association” between women’s vitamin D concentration and the risk of premature birth “in the general obstetrical population at an urban medical center treating a large, diverse population of women,” the researchers wrote.
The protective effect also covered women who initially had low levels of vitamin D but who increased their concentrations during pregnancy, compared with those whose concentrations remained at low levels throughout their pregnancy.
The results were consistent across race and ethnic groups, and also applied to women with a previous preterm birth.
“Vitamin D status is a key modifiable maternal risk factor for the prevention of” preterm birth, the researchers wrote. “The findings from this analysis support the previously identified association between higher maternal [vitamin D] concentrations and reduced risk” of premature birth.
The results also confirmed the notion that the benefits of vitamin D described in previous clinical trials can apply to a general obstetrical population, the team added.