We all know that nature can be cruel at times. Even when something as wonderful as the birth of a new baby is involved, nature — in the form of genetic fate — can dole out unexpected and not always favorable challenges. And now, as technology makes genetic screening of fetuses easier than in the past, the big question more and more parents-to-be will likely be facing is, do you actively want to know beforehand if something may not be quite right with the little one you’re expecting. Here in Japan, some early data on a new prenatal screening procedure has recently been announced, providing us with some sobering food for thought, and we thought we’d share with you a summary of the reports.
When you hear about prenatal tests, amniocentesis may be the one that comes to mind. However, there is now a new kind of screening procedure which can be done more easily, albeit on a more limited basis, for three specific chromosomal disorders in the fetus. It is called non-invasive prenatal (genetic) testing or NIPT for short, and it can be done simply by drawing a blood sample from the mother during early pregnancy, usually at around 10 weeks. The procedure is designed to test for increased risks of Down Syndrome (trisomy 21), trisomy 18 and trisomy 13, all conditions in which there are three copies of the affected chromosome instead of the usual two.
Although NIPT can be a very useful tool, it does not provide a confirmed diagnosis and is not meant to replace established diagnostic tests like amniocentesis or chorionic villus sampling (CVS). Instead, NIPT is meant to serve as a screening process to identify fetuses with an increased chance of carrying the three genetic conditions, after which amniocentesis or CVS can be conducted to confirm the diagnosis. It does, however, have the advantage of being quite accurate, with a 98-99% detection rate for Down Syndrome and a somewhat lower accuracy for the other two disorders, while being non-invasive and posing no risk to the fetus, since it only involves taking some blood from the mother.
In Japan, the test has been available since April of this year on a clinical trial basis at approximately 30 medical institutions approved by the Japanese Association of Medical Sciences and at this time is conducted only in what are considered high-risk cases meeting certain criteria, such as the mother being over 35 years old when giving birth, past history of a child with one of the three genetic disorders or other factors that can increase the chance of the conditions occurring in the fetus, such as abnormal serum and/or ultrasound findings or incidence of chromosomal translocation in either parent.
Although NIPT is an expensive procedure, costing about US$2,000 in Japan, medical groups reported that there were about 3,500 pregnant women who underwent the testing during the first six months it became available in the country. Of these women, 67 tested positive with results indicating a high possibility of the fetus having one of the chromosomal disorders. After further testing, actual chromosomal abnormalities were confirmed in the fetus of 56 of the women.
What did these women decide to do? While two women unfortunately miscarried and one had not been able to make up her mind at the time the information was collected, the remaining 53 women decided to have their pregnancy terminated. We can only imagine how difficult that decision must have been. There was apparently also one woman who after receiving a positive NIPT result, went on to have an abortion without getting the finding confirmed with a more definitive test such as amniocentesis.
While the decision is obviously a highly private matter and completely up to the couple, when asked the reason for terminating the pregnancy, 37% of the women who had an abortion said that it was because the prognosis for the baby’s condition was considered poor. Another 21% of the women said that they didn’t feel confident they would be able to raise the child, while there was also an equal 21% of the women who said the condition made them feel too insecure about the future. Whatever their reasons, we don’t think anyone can criticize the couples for making their decision one way or another.
It should be kept in mind that NIPT is not a perfect test and as already mentioned, should be considered only as a preliminary screening process. In this particular group of women, there were six false positives which turned out to be negative with further testing and also one false negative where a disorder was discovered later. But used in conjunction with other diagnostic tests, it is still a highly effective tool to screen for potential high-risk pregnancies.
That being said and all the technology aside, would you want to know about possible chromosome abnormalities in your unborn child? Once you know, you have to make a decision, and it could be a terribly painful one. Is not knowing better than having to make that kind of decision? Or would you rather know and have a choice? We guess these are questions you simply can’t answer until you’re actually in that situation. Now, while that is something we hope certainly never happens, the report did provide us with a chance to do some serious soul-searching and also be grateful for our blessings in life — and in our opinion, any opportunity to count our blessings is always precious. So thank you, dear reader, for sharing that experience with us!
Source: NHK NEWS WEB (Japanese) and Mount Sinai Hospital website
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