Experts Say Recommendations Are Result of Improvements in Low-risk Tests
SAN DIEGO, CA, JULY 13, 2007 — For almost four decades, prenatal screening for Down syndrome (DS) has been an important component in the care of pregnant women. And for the past 20 years, these screening efforts have focused on biochemical markers in maternal serum, most notably the second-trimester “triple screen,” which has been the standard of care in prenatal chromosomal screening for over a decade.
But earlier this year, the American College of Obstetricians and Gynecologists (ACOG) revised its screening guidelines to now recommend offering fetal chromosomal screening to all pregnant women, regardless of age, because of improvements in low-risk, non-invasive tests.
“Amniocentesis is still the gold standard for diagnosis of fetal chromosome abnormalities,” explained Jacob Canick, PhD, from Women and Infant’s Hospital in Providence, RI, “but it’s an invasive procedure that carries a far greater degree of risk for the pregnancy than a non-invasive screening test.”
The ACOG guidelines note that improvements in prenatal screening tests for Down syndrome have led to higher detection rates and fewer false-positive results, which in turn have led to an increase in the number of women being screened. But not only have the test gotten better, researchers have developed new screening methods that allow for earlier testing so that patients have more time to make very personal decisions concerning their pregnancies.
Currently, the most popular Down syndrome screening option is the second trimester serum quad screen—consisting of alpha-fetoprotein, unconjugated estriol, inhibin A, and human chorionic gonadotropin. But ongoing research has shown clinical utility in a first trimester ultrasound and biochemical testing, as well as integrated screening that incorporates tests in both the first and second trimesters.
“The new ACOG guidelines are a big departure from earlier recommendations,” noted Canick. “They say that all pregnant women are candidates for screening, regardless of maternal age,” he added. “In addition, they suggest that first-trimester screening and integrated screening have a place in prenatal care, and they recommend serum-based screening when first-trimester ultrasound is not available. These approaches could be a breakthrough in the performance of prenatal screening for Down syndrome. We have an opportunity to spare almost all pregnant women the risk of amniocentesis, yet attain detection levels approaching 90%.”
Dr. Canick and colleagues will be discussing these issues in a full-day session on Sunday, July 15, during AACC’s Annual Meeting at the San Diego Convention Center (Room 9), and on Monday, July 16, at a symposium titled “Emerging Assays for Health Management and Optimization Before, During, and After Pregnancy (Room 6F). The meeting attracts 20,000 physicians, scientists and other professionals interested in laboratory science and medicine. More than 200 educational sessions will present the latest information on a wide range of topics in science and medicine. For more information on AACC, visit www.aacc.org.
Interviews with Dr. Canick may be arranged by contacting Brian Ruberry at (619) 525-6227.