A blood-based prenatal test to detect chromosomal abnormalities in fetuses has surged in popularity since debuting in April, with most women who test positive opting for abortions, a study presented at a meeting of genetics experts showed Friday.
The study said 53 out of 56 who received confirmation of testing positive for genetic anomalies chose to terminate pregnancy, while a “very small” number of people aborted after preliminarily testing positive before confirmation, raising concern the test may lead to unnecessary terminations.
A total of 3,514 women took the test in the first six months it was available, compared with 1,534 in the first three months, according to the report, drafted by a group of 25 hospitals across Japan that perform the new prenatal test.
The presentation was made at a meeting of the Japan Society of Human Genetics in Sendai.
Among reasons for taking the test, 94.2 percent cited concerns about advanced-age pregnancy, which roughly pertains to expectant mothers 35 or older. Those whose fetuses tested positive for Down syndrome in the blood diagnosis had an average age of 40.1.
Another 2.4 percent cited a history of pregnancy with chromosomal abnormalities for taking the test, while 1.4 percent said they were told they were at high risk for abnormalities after ultrasound diagnosis.
Of the 67 who tested positive, 62 took the amniotic fluid test to get a definitive diagnosis. Down syndrome and two other genetic disorders were detected in the fetuses of 56 people; six were confirmed as free of abnormalities.
Among those who opted for abortion, the biggest reason cited was that the condition of the fetus was “not good” (37 percent), followed by 21 percent who said they had “no confidence about giving birth to and raising children with chromosomal anomalies,” and 21 percent who said they felt “anxiety about planning for their future.”
The others cited fears about “leaving children behind after death and increasing the burden on siblings” (17 percent) or economic concerns (4 percent).
Kunio Tamai, chief director of the Japan Down Syndrome Society, which supports sufferers and their families, said prospective parents should look deeper into what it means to live with a chromosomal abnormality.
“I believe that by learning how children with disabilities are coping in society, people can imagine being parents (of such children) and their sense of anxiety may change,” he said.
He also noted the widespread need for counseling — not just for those intent on taking the test, but for schoolchildren, teachers and society in general as well.
The prenatal blood test was developed in part to avoid the hazards of amneocentesis, a test that can cause miscarriages because it involves withdrawing amniotic fluid from the fetus.
Koji Kugu, a gynecology professor at Toho University, said the blood test raises several issues.
“Since it’s relatively easy on the body, people may take it casually. We need to provide counseling on genetics by fully considering not just those people who will be parents, but also the children being born,” he said.
According to the health ministry, abortions in Japan are being carried out at a pace of around 200,000 per year. Technically by law, requesting an abortion on the grounds of chromosomal abnormality is illegal.
Conventional serum marker and amniotic fluid tests are performed on more than 10,000 women each year. A considerable number of those women are believed to opt for abortions after receiving confirmation of an anomaly.
In the latest study, of the 3,438 who tested negative for chromosomal abnormalities, one was later found to have one, the group said, adding that it is closely studying the false negative.
The group said 168 people decided not to take the test after being counseled on genetic matters.
The guidelines for the prenatal test were stipulated by the Japan Society of Obstetrics and Gynecology before the test initially became available in April at 15 facilities approved by the Japanese Association of Medical Sciences. As of Oct. 15, 31 facilities had been approved to offer the test.