Finding the causes of prematurity
About half of premature births result from spontaneous preterm labor, the causes of which are unknown. Family studies suggest that genetic factors may contribute to about 40 percent of preterm births. However, we do not know which genes may be involved. Jeffrey C. Murray, MD, of the University of Iowa, is conducting a genome-wide search for variant genes that may play a role in preterm labor, and for environmental factors that may interact with them to trigger labor. This information could lead to better ways to identify women at high risk of preterm labor and treatments to prevent it.
Infections are among the environmental factors that have long been suspected of contributing to preterm labor. Although no specific bacterium has been linked to preterm labor, studies suggest that the body’s natural immune response to infections may trigger labor. A number of March of Dimes grantees are seeking to improve understanding of a possible pathway from infection to preterm labor. For example, Tippi C. MacKensie, MD, of the University of California at San Francisco, is investigating how specific immune cells in the mother may help trigger labor after an infection. Sudhansu K. Dey, of Cincinnati Children’s Hospital Medical Center, is studying chemicals that regulate inflammation after a uterine infection in order to learn how to control inflammation and prevent preterm labor.
Could the air that pregnant women breathe affect their chances of delivering too soon? Judith T. Zelikoff, PhD, of New York University School of Medicine, is seeking direct cause-and-effect evidence that particulate air pollution at levels found in many U.S. cities increases the risk of premature delivery. This could lead to establishment of guidelines to help protect the health of mothers and babies.
Most common questions
How many babies are born prematurely each year?
In the United States, more than 450,000 babies are born too soon each year. Worldwide, 15 million babies are born prematurely.
What are the consequences of premature birth?
Prematurity is the leading cause of death in the first month of life. Worldwide, more than one million children die each year due to complications of premature birth. Babies who survive an early birth often face the risk of lifetime health challenges, such as intellectual disabilities, cerebral palsy, breathing problems, and vision and hearing loss.
Why is it important for a pregnancy to last at least 39 weeks?
If a pregnancy is healthy, it should go to at least 39 weeks. That’s because babies born at 39 and 40 completed weeks of pregnancy (called full term) have the best chance of a healthy start in life. Even babies born at 37 and 38 weeks (called early term) have a higher risk of newborn complications, like breathing problems. Babies born prematurely (before 37 weeks) have a higher risk of newborn health problems and lasting disabilities.