Vitamin D to combat preterm birth

Infections involving the uterus and placenta are a leading cause of preterm birth, especially the earliest ones that pose the biggest risk to the baby. Because most pregnant women will experience no symptoms until they go into early labor, the infections are difficult to diagnose and treat. Martin Hewison, PhD, a March of Dimes Prematurity Research Initiative grantee at the University of California in Los Angeles, is investigating whether vitamin D can stimulate the immune system to fight off infections and help prevent preterm birth.

“Preterm birth is a particular problem for African-American mothers. Compared to caucasian mothers, they are almost twice as likely to deliver early,” says Dr. Hewison. African-American women also are more likely to have low levels of vitamin D in their blood, at least in part because people with darker skin filter more sunlight, which is required for the conversation of the inactive provitamin to the active form of the vitamin. Adding vitamin D to the diets of African-American moms-to-be may be beneficial. Because vitamin D is toxic in excessive doses, this should be done cautiously.

“Our preliminary data suggest that vitamin D fulfills a unique function in pregnancy by both enhancing bacterial killing and suppressing associated inflammation,” says Dr. Hewison. Uterine inflammation, which often results from infection, appears to play an important role in triggering preterm labor. If the results of his study are confirmed, his ultimate goal is to develop cheap and effective vitamin D supplementation regimens that could help prevent infection-related preterm deliveries in African-American moms-to-be and other pregnant women.

Most common questions

Is premature birth a serious health problem?

Yes. Premature babies are at increased risk of newborn health complications, including breathing and intestinal problems and bleeding in the brain. They also are at increased risk of death and lasting disabilities, including intellectual disabilities, behavioral problems, cerebral palsy and vision and hearing loss.

What is late-preterm birth?

Late-preterm birth refers to babies born between 34 and 36 weeks of pregnancy. More than 70 percent of premature babies are born at this time. While these babies are usually healthier than babies born earlier, they are 3 times more likely to die in the first year of life than full-term infants. They also are at increased risk of newborn health problems, including breathing and feeding problems. Some late-preterm births result from early induction of labor or cesarean delivery due to pregnancy complications. However, in some cases, early delivery may occur without good medical justification. Unless there are medical problems, women should wait until at least 39 weeks to schedule an induced labor or c-section to prevent possible prematurity-related problems in their babies.

Which women are at greatest risk for premature birth?

Three groups of women are at greatest risk. These include women who have had a previous premature birth, women who are pregnant with twins or more, and women with certain abnormalities of the uterus and cervix. Treatment during pregnancy with the hormone progesterone can help reduce the risk of another premature birth in some women who have had a previous premature birth. These women should discuss with their health care provider whether this treatment is right for them.

©2013 March of Dimes Foundation. The March of Dimes is a non-profit organization recognized as tax-exempt under Internal Revenue Code section 501(c)(3).