The case for prenatal Down Syndrome test

She and her husband already had two young sons. As is customary in Germany for pregnant women over 35, Susanne underwent a first-trimester screening. Her blood was taken, and the baby’s nuchal fold was examined via ultrasound. The tests showed an increased probability that her child could have a chromosomal disorder such as trisomy 21, also known as Down syndrome.

A referral to a human geneticist and further tests followed. Here, the family got confirmation: A significant probability that Susanne would give birth to a child with Down syndrome. At that time, in 2008, the only way to obtain even more certainty was through invasive tests, such as amniocentesis. The procedure provides more information, but also carries a 0.5 percent risk of miscarriage. Susanne and her husband chose not to have the procedure, albeit for another reason.

“You have to think about what you’re going to do with the results beforehand,” Susanne says. “And it was clear to us that we would not terminate the pregnancy because of Down syndrome.” When daughter Luise was born, the delivering doctor, who was not a trisomy expert, wasn’t sure whether the baby had Down syndrome or not. It didn’t matter to Susanne at that moment.

“It’s simply a baby and it’s our baby,” is what she remembers thinking after the delivery. It wasn’t until the next day that the expert who had been called in diagnosed Luise with trisomy 21. Today, the soon-to-be 13-year-old attends a school for children with disabilities, and a severe heart defect that was operated on shortly before her second birthday has healed. Luise leads a “completely normal schoolgirl life,” says her mother. Since 2012, pregnant women in Germany have also had the option of having a possible chromosomal disorder in their baby diagnosed via a non-invasive prenatal test (NIPT). For a NIPT, a blood sample from the pregnant woman is examined.

The detection rate for trisomy 21 is about 99%. The detection rate for trisomy 18 is 98% and close to 100% for trisomy 13 . The latter two are severe chromosomal disorders, some of which cause children to die in the womb or have such severe physical deformities that they would not survive long after birth.

People born with trisomy 21 have three copies of chromosome 21 instead of two. They usually have mild mental disabilities, in a few cases severe, and motor disorders. 40 to 60 percent have a congenital heart defect, and malformations of the gastrointestinal tract are also not uncommon. Many of the physical anomalies are operable, and the life expectancy of people with Down syndrome averages about 60 years.

Since 2019, the NIPT has been paid for by health insurance in Germany in pregnancies with an increased risk, following a doctor’s recommendation. The move, like the initial introduction of the test, was controversial. Critics worry that the NIPT could be used as an easy way to screen out people with disabilities before they are born, like when women abort babies because of a high likelihood of trisomy 21.

In Denmark, a non-invasive test that can determine with near certainty whether a child will have trisomy 13, 18 or 21 has been part of the normal screening package offered to every pregnant woman since 2004. There is no additional cost to the women; almost all opt to have it. Of those who get a Down syndrome diagnosis, more than 95 percent opt for an abortion, reports the US magazine The Atlantic.

That has radical consequences. In 2019, 18 children with Down syndrome were born across Denmark. In the U.S., there are about 6,000 children born with Down syndrome every year. For Germany there is no comparable statistic. Currently, about 50,000 people with Down syndrome are estimated to live in Germany.

This article was provided by Deutsche Welle