New test for Down syndrome can give expectant parents peace of mind
Monday, December 04 2006, 12:13 AM EST
Contributed by: Pam Adams
EASING WORRIES
Dena Ratcliff is lying on an examining bed in her obstetrician's office, bulging belly exposed. Her husband, Mike, and her parents, Pat and Nell Kelley, pack into the small room also, for a standing-room-only screening of Ratcliff's latest in-utero "video," better known as a sonogram.
The baby's cerebellum looks normal, sonographer Cindy Bornsheuer assures them as she rubs a camera-like piece of equipment, the transducer, across Dena Ratcliff's stomach.
The transducer transforms the murky outlines of a fetus into grainy black-and-white images on a computer screen.
Through the ever-advancing wonders of sonography, Bornsheuer reassures them the fetal heart rate, spinal fluid production and other vital indicators are progressing normally. She points out the ear and the little hairs growing on the back of the baby's head, she tells them the baby's bladder is full, which indicates the kidneys are working.
If Bornsheuer's tone is meant to reduce an expectant couple's anxiety, it is doubly so for Dena and Mike Ratcliff, who at 37 and 45, respectively, are at higher risk of having a baby with Down syndrome.
DOWN SYNDROME
This is Dena's regular sonogram, but earlier in her pregnancy she underwent ultrasound testing geared specifically to Down syndrome risks.
"There's the boy parts, right between the legs," Bornsheuer mentions.
"Good place for them," Mike Ratcliff deadpans.
Dena Ratcliff's father, in particular, is fascinated by the scenes on the computer screen. He and Mike are already searching for signs of whether the boy will be a right- or left-handed pitcher.
"He looks like a little alien," Pat Kelley jokes
As natural and open as their family moments are, the Ratcliffs purposely avoided certain topics throughout the past six months of Dena's pregnancy, such as:
What would they do if early tests showed the baby was at high risk of Down syndrome? Would they opt for a second round of tests, more accurate, yet invasive and with subsequent risk of miscarriage?
What if they went with the invasive procedure, amniocentesis? What if it showed the baby did have Down syndrome? Then what?
The Ratcliffs didn't have to face the difficult questions because of new, more reliable prenatal screening now available through Methodist Medical Center's Perinatology Group in Peoria, Ill.
The tests access risks for Down syndrome or other chromosomal abnormalities early during a woman's pregnancy, which offers several distinct advantages over traditional procedures, according to Dr. Charles Egley.
Methodist's group is currently the only center in Illinois, outside of Chicago, offering the new technology, called a nuchal translucency scan. The Ratcliffs were the first to undergo the new screening locally.
In the past, prenatal testing for risks of chromosomal abnormalities, including the most common one, Down Syndrome, weren't available until the second trimester of pregnancy. With the new screening, tests can be offered during the first trimester, between 11 and 14 weeks of pregnancy.
Not only does the new screening allow for earlier tests, they are more accurate, Egley says. First trimester screenings, a combination of blood tests and specialized ultrasound scans, are 95 percent accurate, compared to an approximate 75 percent accuracy rate for traditional second-trimester screenings.
Traditional screening methods also had higher false-positive rates, which results in unnecessary amniocentesis procedures.
Egley acknowledges screening for Down syndrome, regardless of the method, produces difficult moral questions.
"Part of this becomes an ethical issue of what do you do with the information," he says. "The only medical reason for offering (screenings) is for a woman to decide whether or not she wants to terminate a pregnancy."
But knowing the risks are low, particularly early during the pregnancy, can relieve months of unnecessary anxiety, as well as the unnecessary amniocentesis, he adds.
About 30 women, from as far away as Champaign-Urbana and LaSalle-Peru, have undergone the screenings since Methodist began offering them months ago. The tests were cleared for clinical use in 2005. Before then, they were primarily available at university hospitals.
Testing combines the results of bloods tests and the specialized ultrasound, or nuchal translucency scan, along with other factors such as the mother's age, to calculate the likelihood of chromosomal abnormalities. Doctors and sonographers must undergo training and reviews to be certified to perform the tests.
Babies with Down syndrome tend to have a translucent area at the base of their necks, hence the name nuchal translucency scan. Researchers are also beginning to look at other indicators, such as measuring the nasal bone of the fetus.
Decisions about screenings or further procedures, such as amniocentesis, are individual and personal for each family, says Meri Tucker, president of the Heart of Illinois Down Syndrome Association Inc.
"There are no right or wrong answers," Egley says.
The Ratcliffs chose to undergo the early screening because of her age and that Dena, who was adopted, had only a cursory background about her birth family's medical history.
They have not thought about what they would have done if the results of her first trimester screening had come back differently.
"That difficult discussion? They took that away from us," Dena says. It's clear she and Mike didn't mind one bit.
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