Pregnant women with low levels of vitamin D are more likely to give birth prematurely, according to a new study. Premature birth can lead to lifelong health problems for the early arrival, according to the March of Dimes, including issues in the lungs, brain, eyes, ears and digestive and immune systems.
Researchers from the University of Pittsburgh analyzed data for 2100 women who gave birth on time and more than 1100 who delivered prematurely. They found a strong association between vitamin D levels and preterm birth. The study was published in Obstetrics & Gynecology.
Women with the lowest levels of vitamin D were about 1.5 times as likely to deliver early compared to those with the highest levels, the investigators found. That finding held true even after the researchers accounted for other factors linked to preterm birth, such as obesity, and smoking, according to a release about the research from the National Institutes of Health. The U.S. Centers for Disease Control and prevention provided funding for the research.
"Mothers who were deficient in vitamin D in early parts of pregnancy were more likely to deliver early, preterm, than women who did not have vitamin D deficiency," said study leader Lisa Bodnar, associate professor of epidemiology and obstetrics and gynecology at the University of Pittsburgh, in the release.
Pregnant women should get 600 international units (IUs) of vitamin D daily according to the Institute of Medicine's Food and Nutrition Board.
Previous studies on vitamin D levels and their effects on early delivery have been mixed, according to Bodnar. "One or two large studies showed vitamin D deficiency increased the risk," she said. However, smaller studies found no link.
How does D help the baby wait until its due date? Bodnar believes the vitamin may help reduce bacterial infection in the placenta, which can trigger an early delivery.
Adequate vitamin D during pregnancy may help babies in other ways as well. Research published last year suggests children are likely to have stronger muscles if their mothers had a higher level of vitamin D in their body during pregnancy.