Stillbirth is a tragedy that occurs in one of every 160 births in the United States. Compounding the sadness for many families, the standard medical test used to examine fetal chromosomes often can't pin down what caused their baby to die in utero. In most cases, the cause of the stillbirth is not immediately known. The traditional way to determine what happened is to examine the baby's chromosomes using a technique called karyotyping. This method leaves much to be desired because, in many cases, it fails to provide any result at all. Today, some 25 to 60 percent of stillbirths are still unexplained.
A new test for analyzing the chromosomes of stillborn babies, known as microarray analysis, has now proven 40 percent more effective in pinpointing potential genetic causes of death than the old karyotype testing procedure. Researchers at the University of Texas Medical Branch at Galveston, along with a team of other national leaders in maternal-fetal medicine, have published their findings in the Dec. 6 New England Journal of Medicine.
"Families have a much greater sense of closure if they understand what likely caused their baby to die," said Dr. George Saade, lead investigator of the UTMB arm of the study. "And for doctors to be able to see more genetic information about each stillborn baby can only be a good thing in terms of continuing the fight to reduce stillbirths worldwide."
Stillbirth, as defined separately from miscarriage, is when a baby dies in the womb prior to delivery at or after 20 weeks of gestation.
The study, part of the National Institutes of Health Stillbirth Collaborative Research Network's ongoing program, showed that microarray analysis genetic testing offers families strikingly more information than karyotyping about what potentially caused their baby to die before it was born. UTMB's Saade is the lead investigator for the study at UTMB, and chairman of the genetics committee for the Stillbirth Network.
The researchers compared the results of karyotypes from more than 500 stillbirths to results from microarray analysis, a method that detects small segments of missing parts of chromosomes (deletions) or additional sections of genetic material (duplications) that cannot be seen by karyotyping.
They analyzed samples from all stillbirths in a population-based study in five U.S. areas, covered by 59 hospitals over a period of two and a half years. Shortly after each stillbirth, parents gave research staff permission to collect blood from the umbilical cord and tissue from the fetus and the placenta.