Since the introduction of non-invasive screening methods, the number of amniocentesis has halved in France. This decrease made it possible to avoid between 187 and 375 miscarriages.
In recent years, screening for Down’s syndrome has changed a lot. Until 2009, invasive and painful fetal samples, such as amniocentesis, were the only screening methods.
But faced with the risks inherent in this practice (miscarriages, infections), the development of alternatives seemed essential. Non-invasive screening, introduced in 2009, relies on ultrasound and biochemical measurements. Made at 1er trimester of pregnancy, these combined tests made it possible to reduce the frequency of invasive samples by half, reveals the weekly epidemiological bulletin (BEH) published this Tuesday.
Non-invasive screening is based on measurement of nuchal translucency (accumulation of fluid in the neck of the fetus) and the use of maternal serum markers for trisomy 21. It is offered to all pregnant women. According to the study carried out by the Biomedicine Agency, this method represented 70% of all tests used.
Decrease in invasive acts
This “evolution was accompanied by a 47% decrease in invasive samples for diagnostic purposes (amniocentesis or chorionic villus biopsy) during the period studied, from 79,107 in 2009 to 41,627 in 2012”, indicate the authors. This decrease in the number of invasive procedures has prevented, on average, more than 200 miscarriages.
However, “despite this significant decrease in the number of invasive samples, the number of prenatal diagnoses of trisomy 21 has increased steadily, from 1918 in 2009 to 1970 in 2012”, indicate the authors.
Blood tests: future revolution
According to these specialists, the implementation of screening combined with 1er trimester was made possible thanks to a massive buy-in from pregnant women and their doctors. “This screening could nevertheless undergo significant changes with the methods of analysis of free fetal DNA in maternal blood”, they explain.
These blood tests have been available in France since 2013 but still remain marginal. Despite their very good results compared to conventional methods, this non-invasive alternative is reserved for women at greatest risk and is not reimbursed by social security. Health authorities are still trying to define their use nationally.
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