Seasons Play A Role in Premature Birth Risk

New research indicates that babies conceived during the summer months are less likely to be born early than those conceived in other seasons, thus reducing the risk of birth complications or conditions such as cerebral palsy .

According to the study, released by researchers at the University of Pittsburgh, women who get pregnant in spring have a 25 percent increased risk of giving birth prematurely than women who conceive during the summer.

“It's very interesting,” said Dr. Marilee Allen, pediatrics professor at Johns Hopkins University School of Medicine. “I think the next step is to really look at the specific things that may be seasonal in exposure—is it related to infections, is it related to allergies, is it related to sunlight?”

Risks Linked to Early Births

A birth is considered premature if the baby is born before 37 weeks of pregnancy. According to the Centers for Disease Control and Prevention, premature births are the leading cause of infant mortality in the nation—accounting for one-third of newborn deaths every year.

Furthermore, studies have shown that babies born too early have an increased risk of developing neurological conditions such as cerebral palsy, autism, or other birth defects.

The health of the mother during pregnancy is particularly important for the proper development of the fetus and placenta, according to Dr. Hyagriv Simhan, co-author of the study and assistant professor of obstetrics, gynecology, and reproductive sciences at Pitt's School of Medicine. When woman are exposed to allergens and viruses in the first days and weeks after conception, it could produce a cellular affect that sets them up for an early birth, he added.

Why Summer?

So why is a summer conception less risky than other seasons? Experts believe that women are more prone to being physically active during the summer, eat healthier foods, and are exposed to more sunlight, which is important in vitamin D production. All these factors could lead to a healthier pregnancy and a lowered risk of premature birth, said Lisa Bodnar, co-author of the study and assistant professor of epidemiology at Pitt's Graduate School of Public Health.

“There's an awful lot that we don't understand about the causes and consequences of prematurity,” said Dr. Michael Gravett, vice chairman of the Department of Obstetrics and Gynecology at the University of Washington School of Medicine. “I'm hoping that this sort of thing that points out the importance of prematurity and seasonality helps doctors rethink how we deliver prenatal care to those at highest risk.”