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Non-Hispanic black women experience preterm birth twice as much as non-Hispanic white women. Why?


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Courtney Mitchell

Oct. 30, 2017

A researcher at the UNC-Chapel Hill School of Medicine has received nearly $4 million from a division of the National Institutes of Health to address minority health disparities related to preterm birth.

Dr. Tracy Manuck, associate professor of obstetrics and gynecology and maternal-fetal medicine specialist, received $3.8 million over five years from the National Institute of Minority Health Disparities to help determine why non-Hispanic black women are twice as likely as women of other races to have more than one preterm birth.

Preterm birth is categorized as delivery before 37-weeks gestation and is the leading cause of death and permanent disabilities for newborns. According the March of Dimes, the rate of preterm birth among African-American women in 2016 was 13.3 percent, nearly 50 percent higher than the rate of preterm birth among white women (nine percent). Between 30 and 50 percent of women with one preterm birth will have another early delivery in their next pregnancy.

“There is a critical gap in our understanding of what causes spontaneous preterm birth, especially for black women,” said Dr. Manuck, who is also director of the UNC Preterm Birth Clinic. “Our typical methods for preterm birth prevention are less likely to be successful in black women, but we don’t know why.”

Administration of the drug 17-alpha hydroxyprogesterone caproate (17P) is now widely used to prevent recurrent spontaneous preterm birth, but data show it is less effective for black women compared with white women. Dr. Manuck’s current research seeks to identify women who will not respond to 17P.

“Our ultimate goal is to identify which women will have another preterm birth despite our best available treatments,” said Dr. Manuck. “Then, we can work on developing new medications to help that group, at a time early enough in pregnancy to still make a difference in outcomes. These therapies can be targeted specifically to their needs and reduce the risk of recurrent preterm birth.”

Babies born prematurely are at greater risk of death or serious disability. Babies who survive may experience problems breathing or feeding, developmental delays and problems with seeing and/or hearing. Having a premature infant may also strain a family’s financial and emotional well-being.

Manuck and her team will collect blood samples from the women enrolled in the study at three time points during pregnancy. They will also save samples from placentas and infants at delivery in order to uncover patterns and commonalities in genomics of women who experience recurrent preterm birth and those who do not.

“Eventually what we’d like to be able to do is apply these findings to not just women with a prior preterm birth but all pregnant women. If we could predict who is at risk for spontaneous preterm birth and who is not by a simple blood draw, we could target our therapies to those who need them the most. This would make a big difference in lives of moms and babies,” she said.

Beyond genomics, Dr. Manuck’s team will also consider psychological factors such as family history, past experiences of trauma, maternal stress and anxiety, and more, as such factors are now seen as possible determinants for decreased health.

The study is now recruiting at N.C. Women’s Hospital and WakeMed Medical Center. Other members of the investigative team include Dr. Carmen Beamon (WakeMed Medical Center), Dr. Rebecca Fry (UNC Gillings School of Global Public Health Department of Environmental Science and Engineering), and Dr. Yun Li (UNC Gillings School of Global Public Health Departments of Biostatistics and Genetics).

For more information on the Preterm Birth Prevention Clinic at UNC, visit

For more information on this grant, visit