Using DNA samples from thousands of women who had delivered preterm babies, scientists led by a March of Dimes researcher have discovered six gene regions that could be crucial to preventing early births, the leading cause of death among babies in the United States.
The findings help answer the challenging question of what causes preterm births and could change the way pregnant women are treated in the doctor’s office.
“It’s probably one of the most exciting discoveries that we’ve had at the March of Dimes as we work to find some causes of preterm births,” said Stacey Stewart, March of Dimes president. “This … is breaking new ground. Up until now we’ve been really unclear about the causes of preterm births.”
The findings are the first to help specifically determine which genetic factors are linked to preterm births, said Dr. Louis Muglia, who coordinated the study.
“We have the first common variants in the mother’s genome that predict the length of gestation and the risk for preterm births,” said Muglia, principal investigator of the March of Dimes Prematurity Research Center — Ohio Collaborative. “And they identify new pathways that can be used for prediction and prevention that we really wouldn’t have thought about before.”
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The study was published online Wednesday by the New England Journal of Medicine.
Researchers first analyzed saliva from nearly 44,000 European women, then confirmed their findings with a study of about 8,600 mothers and 4,100 infants from Nordic birth studies.
Because of some of the genes involved, the research already suggests that the dietary mineral selenium may play a role in pregnancy length, as may the lining of a woman’s uterus. If supported by further research, those findings could lead to new ways of preventing preterm births, said Muglia, who co-directs the Perinatal Institute at the Cincinnati Children’s Hospital Medical Center.
Babies born before 37 weeks of pregnancy are considered preterm and face risk of death and complications that can lead to lifelong conditions. The March of Dimes’ goal is to reduce the U.S. preterm birthrate to 5.5 percent by 2030. It currently is at 9.8 percent.
Ohio, with a rate of 10.3 percent, is above the national rate, as is Franklin County, at 10.4 percent.
When born too soon, infants might die or be permanently impacted with lung, brain, vision or hearing problems that affect a family emotionally and financially, Stewart said.
The study is an exciting one because it provides a prediction tool for spontaneous preterm deliveries, which comprise about 70 percent of all early births, said Lisa Christian, associate professor of psychiatry and behavioral health and who is part of the Institute for Behavioral Medicine Research at Ohio State University’s Wexner Medical Center.
A next step would be to see how the genetic information interacts with environmental circumstances, such as psychological stress levels, sleep patterns, nutrition or smoking behaviors, said Christian, who was not involved in the study. She also would like to see the study replicated in African-American women.
The main limitation, she noted, is that the women involved are only of European descent, which researchers acknowledged. They also acknowledged that self-reporting by some of the women could have affected results.
The study was funded by the March of Dimes, the National Institutes of Health, the Research Council of Norway, the Swedish Research Council and the Bill & Melinda Gates Foundation.
Muglia said the findings are just “the tip of the iceberg” and likely will lead to further genomic findings and other research. Already, he said, the study has initiated a series of large-scale investigations into the use of selenium in pregnant women.
The research is, by far, the most exciting and important thing that he’s been a part of in his career, Muglia said. Finding ways to prevent preterm labor, he added, would impact millions of children around the world.
“Preterm birth is the single-biggest problem in maternal and child health,” he said. “It’s absolutely essential that we make progress.”