New Screening Test Proves Earlier, More Accurate Predictor for Down Syndrome
Columbia-Led Study of More Than 38,000 Women Enables Faster, First Trimester Prenatal Testing for Leading Cause of Mental Retardation and Birth Defects
Nov 9, 2005
A new study from Columbia University Medical Center researchers at NewYork-Presbyterian Hospital/Columbia of more than 38,000 pregnant women at 15 U.S. centers demonstrates the high accuracy of non-invasive screening for Down syndrome (also known as trisomy 21) in the first trimester of pregnancy, at 11 weeks. The findings are a significant advantage over the current standard screening, a blood test performed in the second trimester of pregnancy.
"These results will undoubtedly change national practice all pregnant women should have the option of early screening for Down syndrome in their first trimester," said Mary E. D'Alton, M.D., principal investigator of the study. She is Chair of the Department of Obstetrics and Gynecology at Columbia University College of Physicians and Surgeons, and Chief of Obstetrics and Gynecology at NewYork-Presbyterian Hospital/Columbia. "Down syndrome screenings based on either maternal age alone, or an ultrasound or sonogram alone, are no longer justified protocols."
Published this week in the New England Journal of Medicine (Nov. 10, 2005 issue), the study is known as the FASTER trial (First and Second Trimester Evaluation of Risk). It was funded by a $13 million grant from the National Institutes of Health and the National Institute of Child Health and Human Development one of the largest ever grants for an obstetrical study.
The new screening approach uses a blood test that analyzes the level of a protein and hormone in the mother's blood, combined with an ultrasound or sonogram picture of the thickness of skin on the back of the baby's neck (known as the nuchal translucency or NT). Results are available within five days, often before starting the second trimester of pregnancy. This combination approach determines the odds that the baby might have Down syndrome, allowing pregnant women the option of prenatal diagnosis for Down syndrome and other chromosomal abnormalities within the first trimester or pregnancy. The researchers found higher detection 87 percent in the first trimester compared to the best second trimester screening method 81 percent detection. Results with this new combination screening approach in the first trimester are a significant advantage over the current standard screening test.
First-trimester screening was performed on 38,167 patients; 117 were found to have a fetus with Down syndrome. If a positive result is found via screening, the woman is given the option to have the finding confirmed with a diagnostic exam: chorionic villus sampling (CVS) or amniocentesis. Both tests carry risks of complication leading to miscarriage.
Down syndrome is one of the leading causes of mental retardation and birth defects, found in one in 660 pregnancies. Persons with this condition have distinct physical features and commonly have certain birth defects and medical problems. Any woman can have a baby with Down syndrome, regardless of her age, race, health, economic status or family history. For this reason, most pregnant women undergo testing to determine their potential to have a baby with this syndrome.
Dr. D'Alton and the research team believe that the new screening method should only be administered by qualified, trained physicians. Dr. D'Alton and other experts working with the Society of Maternal Fetal Medicine have recently formed the Maternal Fetal Medicine Foundation to facilitate physician training and quality review for the screening. So far 1,600 physicians and sonographers nationwide have undergone training, and more are scheduled. Information about the training and quality review program can be found at http://www.MFMF.org.
Women seeking this early screening should seek healthcare professionals with appropriate ultrasound training and who participate in ongoing quality monitoring programs. Programs should provide sufficient information and resources for counseling regarding the different screening options and limitations of these tests. Additionally, the services should provide access to an appropriate diagnostic test when the screening test is positive.
"This study was a wonderfully collaborative effort between researchers, including four leading Obstetrics and Gynecology centers in New York City. This incredible achievement would not have been possible without the hard work of the 15 centers that comprised the FASTER Research Consortium and the 38,167 women who participated in this clinical trial," said Dr. D'Alton.
Columbia University Medical Center provides international leadership in pre-clinical and clinical research, in medical and health sciences education, and in patient care. The medical center trains future leaders in health care and includes the dedicated work of many physicians, scientists, nurses, dentists, and public health professionals at the College of Physicians & Surgeons, the School of Dental & Oral Surgery, the School of Nursing, the Mailman School of Public Health, the biomedical departments of the Graduate School of Arts and Sciences, and allied research centers and institutions. Columbia University Medical Center researchers are leading the discovery of novel therapies and advances to address a wide range of health conditions.
New York-Presbyterian Hospital is the largest not-for-profit, non-sectarian hospital in the country. It provides state-of-the art inpatient, ambulatory and preventive care in all areas of medicine at five major centers: New York-Presbyterian hospital/Columbia University Medical Center, New York-Presbyterian Hospital/Weill Cornell Medical Center, Morgan Stanley Children's Hospital of New York-Presbyterian, the Allen Pavilion, and the Westchester Division. It consistently ranks as one of the top hospitals in the country in U.S.News & World Report's guide to "America's Best Hospitals." The New York-Presbyterian Healthcare System an affiliation of acute-care and community hospitals, long-term care facilities, ambulatory sites, and specialty institutes serves one in four patients in the New York metropolitan area.