JAMA articles begin to explain mysteries of stillbirth

UT Medicine San Antonio obstetrician among leaders of the Stillbirth Collaborative Research Network

SAN ANTONIO (Dec. 15, 2011) — Two articles in the latest issue of the Journal of the American Medical Association (JAMA) shed light on stillbirth, which remains poorly understood despite being among the most common adverse outcomes of pregnancy. A UT Medicine San Antonio obstetrician played a key role in the research.

As the San Antonio site director for the Stillbirth Collaborative Research Network, Donald J. Dudley, M.D., led recruitment at 11 local hospitals of women who had experienced 176 stillbirths. Additionally, hundreds of San Antonio women who delivered healthy babies enrolled in the study as control subjects.

San Antonio provided more study participants than any of the other four sites, which included Brown University in Providence, R.I.; Emory University in Atlanta; University of Utah in Salt Lake City; and The University of Texas Medical Branch in Galveston.

“This is the biggest, most diverse study on stillbirths ever done in the United States, and San Antonio was part of it,” said Dr. Dudley, who sees patients through UT Medicine San Antonio, the clinical practice of the School of Medicine at The University of Texas Health Science Center at San Antonio, where he is professor and vice chair for research in the Department of Obstetrics and Gynecology.

Deborah L. Conway, M.D., associate professor of obstetrics and gynecology, and Josefine Heim-Hall, M.D., clinical professor of pathology, also played significant roles.

Stillbirth is defined as fetal death at 20 weeks’ gestation or later. There are roughly 26,000 stillbirths per year in the United States, affecting one in 160 pregnancies. Since 2003, the U.S. stillbirth rate has held at 6.2 stillbirths per 1,000 births, higher than in many developed countries.

The Eunice Kennedy Shriver National Institute of Child Health and Human Development funded the Stillbirth Collaborative Research Network after determining in 2001 that insufficient data existed to understand and address the causes of stillbirth. Study participants were recruited between March 2006 and September 2008, and the Dec. 14 JAMA publications contain the initial results.

Nationwide, 663 women with stillbirth enrolled in the study. Of those, 500 consented to full autopsies of 512 stillborn infants. A probable or possible cause was pinpointed in 76 percent of those stillbirths.

Previously, it was known that significant racial and ethnic disparities exist in stillbirths. Of every 1,000 births, there are 11.13 stillbirths among non-Hispanic black women and 5.44 stillbirths among Hispanics, compared with 4.79 among non-Hispanic white women. Although the reasons behind those disparities remain mysterious, one of the JAMA articles describes the differences in greater detail.

The study found that non-Hispanic black women experience a higher proportion of stillbirths due to infection and obstetric complications, which can range from placental abruption, complications of multiple gestation, cervical insufficiency and preterm labor or premature rupture of membranes. For black women, stillbirths often occur “intrapartum,” or during labor, and at less than 24 weeks’ gestation.

Meanwhile, Hispanic and non-Hispanic white women experience a higher proportion of stillbirth due to cord abnormalities compared with other women.

The study also examined known risk factors for stillbirth, particularly focusing on those that would have been apparent at the start of pregnancy.

The analysis confirmed a number of factors associated with stillbirth: non-Hispanic black race/ethnicity; diabetes; age of 40 or older; AB blood type; history of drug use with addiction; cigarette smoking in the three months prior to pregnancy; being overweight or obese; and not living with a partner. But the researchers found that, apart from previous stillbirth or pregnancy loss, risk factors known at the beginning of pregnancy have little predictive value.

Dr. Dudley said researchers will continue to analyze the data they have, which in turn will help them to design new studies on stillbirth: “We’ve barely scratched the surface.”

UT Medicine San Antonio is the clinical practice of the School of Medicine at The University of Texas Health Science Center San Antonio. With more than 700 doctors – all faculty from the School of Medicine – UT Medicine is the largest medical practice in Central and South Texas, with expertise in more than 60 different branches of medicine. Primary care doctors and specialists see patients in private practice at UT Medicine’s clinical home, the Medical Arts & Research Center (MARC), located in the South Texas Medical Center at 8300 Floyd Curl Drive, San Antonio 78229. Most major health plans are accepted, and there are clinics and physicians at several local and regional hospitals, including CHRISTUS Santa Rosa, University Hospital and Baptist Medical Center. Call (210) 450-9000 to schedule an appointment, or visit the Web site at www.UTMedicine.org for a complete listing of clinics and phone numbers.

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