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What is the early detection of Down’s syndrome?
Le early detection of Down’s syndrome occurs during the first trimester (between the 11th and 13th week of amenorrhea). Carried out in one go, this screening combines three parameters:mother’s age, biochemical marker assays andscan(nuchal translucency of the fetus). Women aged 38 and over no longer have to systematically do a amniocentesis, they can benefit, as a first step, from combined screening of the first trimester. Objective: to limit as much as possible the use of invasive samples, causing 0,1% of miscarriages.
All pregnant women should be informed of the possibility of using combined screening to assess the risk of Down’s syndrome for the unborn child. She is free to refuse or agree to take this test, but in all cases she must expressly give her consent.
>>> To read also: All about amniocentesis
What are the benefits of combined screening for Down’s syndrome?
Of course, early detection of trisomy 21 implies that pregnant women meet their doctor early enough and that he gives them the right information. If so, then the benefits of re-screening are manifold. It allows to know the level of risk early, from the first trimester of pregnancy. This is widely appreciated by future mothers and saves them often unnecessary stress.
This device also limits the use of invasive tests (amniocentesis or trophoblast biopsy) which were systematic in pregnant women over 38 years of age before 2010. It is above all more efficient in terms of sensitivity and makes it possible to reduce the number of ” false positives ».
>>> To read also:Parents of a child with Down’s syndrome, who to contact for follow-up?
Non-invasive prenatal screening, a new test now reimbursed
A new trisomy 21 prenatal screening test has been tested in certain French maternity hospitals. It will now be offered in the care program for pregnant women. This test is the Non-Invasive Prenatal Diagnosis (or DPNI) ou free circulating DNA tests for trisomy 21 in maternal blood. Concretely, it is a molecular biology technique which consists in taking fetal DNA from the mother’s plasma and then sequencing it in order to read its genetic code and therefore identify the markers of Down’s syndrome.
Since May 2017, the High Authority of Health (HAS) recommends offering this test after the screening test precocious first trimester combined, women whose estimated risk level is between 1/1000 and 1/51. It makes it possible to further limit the number of amniocentesis and other invasive samples.
Note that the non-invasive prenatal screening is now 100% covered by Health Insurance, and therefore reimbursed in France since December 27, 2018.