In 2006 the Eunice Kennedy Shriver National Institute of Child Health and Human Development established the Stillbirth Collaborative Research Network (SCRN) to tackle the persistent issue of stillbirth in the United States, which occurs in one of every 160 pregnancies, totaling nearly 26,000 per year. The SCRN conducted two population-based studies, one to determine the causes of fetal demise and one to evaluate the associated risk factors that can be identified at the start of a pregnancy.

Between 2006 and 2008, the researchers collected data on stillbirths and live births at delivery from 59 tertiary care and community hospitals in five racially and geographically diverse states.

The cause-of-death study analyzed 512 stillborns (from 500 women). The most clinically useful tests in determining the cause of death were a histologic evaluation of the placenta, a perinatal autopsy, and karyotype (chromosomal) testing; in three-quarters of all cases, a probable or possible cause of death was established, and these tests combined detected the cause of death in 340 cases (66%). The leading causes of stillbirth in the study were obstetric complications (29%), which included conditions such as placental abruption, multiple births, and preterm labor; placental defects (24%), such as uteroplacental insufficiency or vessel disorders; genetic and structural issues of the fetus (14%); infections (13%); umbilical cord defects (10%); blood pressure disorders (9%); and medical issues in the mother (8%).

The cause-of-death study also found that non-Hispanic black women have double the risk of stillbirth that non-Hispanic white women have. The excess rate of stillbirth in non-Hispanic black women was primarily a result of obstetric complications, infections, early gestational age (20 to 24 weeks), and stillbirths occurring during labor.

The SCRN's study of risk factors observable in women at the start of their pregnancies revealed a number of factors associated with stillbirth in the newly pregnant women when their demographic and clinical characteristics were compared with those of controls (women whose babies were not stillborn): a history of stillbirth, black race, previous miscarriage before 20 weeks, obesity or overweight, older age, and nulliparity were all independently associated with a higher risk of stillborn birth. The researchers cautioned, however, that these factors "explained little of the overall burden of stillbirth."-AK

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