Pregnant women can find out earlier, with more accuracy, their risk of carrying a baby who has Down syndrome, according to results of a national study that included four Utah hospitals. And the test is noninvasive.

LDS Hospital, University Health Care, McKay-Dee Hospital and Utah Valley Regional Medical Center were among 15 centers that participated in the "FASTER" clinical trial, which stood for First And Second Trimester Evaluation of Risk for aneuploidy. Utah women accounted for 12,000 of the study's 38,000 women total.

Results are being published today in the New England Journal of Medicine. The $11 million study is the largest obstetrical-maternal study ever funded by the National Institutes of Health.

Local fetal-medicine experts predict that the new test will eventually become the standard of care and decrease use of amniocentesis testing in mothers 35 and older. Testing the amniotic fluid to look for chromosome abnormalities like Down syndrome carries a one in 250 risk of complication, including miscarriage.

Traditionally, women undergo testing in the second trimester at about week 15-20, using a "triple screen" that looks at three markers in a woman's blood to see if it's likely she's carrying a baby with fetal Down syndrome. The triple screen has a higher false-positive rate than the new test, said Dr. T. Flint Porter, medical director of the maternal-fetal medicine program at LDS Hospital and the principal investigator of the study at both LDS Hospital and University Hospital.

The study compared traditional second-trimester screening for Down syndrome with first-trimester screening and an "integrated" screening that uses both the first- and second-trimester methods to calculate the risk.

They found that the first-trimester screen, which involves an ultrasound of the back of the baby's neck and maternal blood tests 11 to 13 weeks into the pregnancy, improves detection of Down syndrome to more than 90 percent accuracy compared to the roughly 60 percent for second-trimester screening alone. And the number of women who had false positives (amniocentesis is used to confirm a positive finding) dropped from above 5 percent to below 2 percent.

For the vast majority of women, the results with be good news regardless of the test, said Porter. Most women will test negative and it will improve peace of mind.

It was for that peace of mind that Suzanne Attix enrolled in the FASTER study when she was pregnant at age 35. She'd unexpectedly lost a baby she was carrying before that and was nervous. She also didn't want to have amniocentesis because she didn't want to expose the baby she was carrying to any added risk.

She got the peace she craved. The two parts of the integrated test calculated her risk at one in 5,000 and one in 9,000. That was good enough for her, she said, and she opted to forego further testing. Her daughter is now 3 years old and healthy.

"I think this should be available to any women," Attix said. "I think the more choices we have to get information about our unborn children, the better we feel."

Risk for Down syndrome is mostly based on the mother's age at time of pregnancy, said Nancy Rose, director of perinatal genetics for Intermountain Health Care. At age 30, a pregnant woman has a one in 1,000 chance of having a baby with Down syndrome. At age 40, it's one in 100.

Because there is no treatment for Down syndrome. The goal of the screening is to improve parental preparedness, said Dr. Jan Byrne of University Health Care, which includes University Hospital. She said some women with positive findings might choose to end the pregnancy.

The new test is now available at centers that participated in the study and is becoming more readily available elsewhere. Insurance covers the cost. Results of the first-trimester test typically take a week, or the woman can choose to come back again at 15 weeks and have the integrated screening using the other tests as well, the results for both to follow.


E-mail: lois@desnews.com