死产的各种成因分析

The Stillbirth Collaborative Research Network (SCRN) has reported that performing a systematic medical evaluation leads to a probable or possible cause of death in the majority of stillbirths. According to a study published in the Dec. 14, 2011 issue of the Journal of the American Medical Association (JAMA), the most common causes of stillbirth differ across racial and ethnic groups, with resulting implications for monitoring and prevention of this devastating pregnancy outcome. The researchers found that the most common causes of stillbirth were obstetric（产科的） conditions, such as cervical（子宫颈的） insufficiency, placental（胎盘的） abruption, or preterm labor, and abnormalities of the placenta. Other common causes included genetic or structural abnormalities of the fetus, umbilical cord（脐带） abnormalities, infection, blood pressure disorders, and other maternal medical conditions. Previous research shows that black women are more than twice as likely to be affected by stillbirth as white women, but the reasons for this disparity are as yet unknown. In this study, the researchers discovered that stillbirths in black women were more likely to occur earlier in the pregnancy or during childbirth and were more likely to be caused by obstetrical complications or infection.

"Stillbirth is more common than people realize, affecting one out of every 160 pregnancies in the United States," says Robert M. Silver, M.D., professor of obstetrics and gynecology, chief of the Division of Maternal-Fetal Medicine at the University of Utah School of Medicine, and senior author on the study. "Our research focuses on determining underlying causes of stillbirth, as well as factors that may contribute to the significant racial disparity in stillbirth rates."

There are approximately 26,000 stillbirths a year in the United States, equivalent to the number of infant deaths that occur each year. Although the stillbirth rate declined steadily from 1990 to 2003, it has remained stagnant（停滞的） since 2003 and is higher than that of many other developed countries. SCRN was created by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) to address this major public health issue. The main objectives of the SCRN include ascertaining the causes and risk factors for stillbirth and finding reasons for racial disparities. For this study, the SCRN recruited a racially and geographically diverse population from 59 hospitals in five states, including Utah. SCRN researchers performed complete postmortem（验尸） examinations on 512 of the 972 stillbirths that occurred in the study areas from March 2006 to September 2008. These postmortem examinations included autopsy, evaluation of the placenta by a perinatal（出生前后的） pathologist, and chromosome testing, in addition to laboratory studies and an interview with the mother. By performing systematic evaluations, the researchers were able to identify a probable or possible cause of death in 390, or 76 percent, of the stillbirths.