In a recommendation validated by its college on September 26, the High Authority for Health (HAS) recommends “ proposer » to pregnant women « the search for chromosomal anomalies compatible with an active pregnancy and likely to lead to particularly serious fetal or obstetric consequences » [1]. Currently focused on the search for possible trisomy 21 (T21) of the fetus, NIPT, non-invasive prenatal screening which consists of analyzing free fetal DNA circulating in the mother’s blood (flcDNA), could thus be extended to trisomies 2, 8, 9, 13, 14, 15, 16, 18, and 22, as well as “ non-cryptic segmental anomalies »[2].
Avoid invasive examinations?
This recommendation from the HAS follows the referral to the General Directorate of Health (DGS) (see DPNI: the HAS referred to expand the “identification” of chromosomal anomalies), and is “ in line with the 2017 HAS recommendations ».
Indeed, in 2018, the “ prenatal screening strategy for Down syndrome » evolved by establishing “ the systematic proposal of an examination of free circulating DNA to any pregnant woman whose combined examination of the first trimester shows a risk of Down syndrome »[3]. By using this type of screening targeting Down syndrome, “ a reduction in the identification of chromosomal anomalies other than T21 due to the reduction in the number of karyotypes [4] » could intervene, believes it can justify the HAS.
Real information?
The health authority also recommends that patients be informed by trained prescribers, “ in order to guarantee the quality of the information delivered and the autonomy of women in decision-making, particularly in the context of an increase in the number of anomalies detected “. The objective is to enable “ an informed decision regarding the performance of screening and diagnostic examinations “. It is up to the Biomedicine Agency (ABM) to define “ information methods for pregnant women ».
Will this information go beyond basic considerations of medical examinations? (see Non-invasive prenatal screening: real consent from women?) Will the reliability of these tests and the uncertainties surrounding the clinical outcome of these unborn children be discussed? Will the right not to know be just as respected? In the event of a positive screening, will women inevitably be pushed towards medical termination of pregnancy or will alternatives be offered to them to support their child? (see “Where is my freedom if I am only offered IMG?”)
Experience in screening for Down syndrome can only call for the greatest caution (see Prenatal screening for Down syndrome: Belgium singled out by the UN; Iceland: almost 100% abortions in cases of Down syndrome).
[1] The authority indicates that it has “ taking into account data from the literature on the frequency of chromosomal abnormalities and clinical characteristics, the performance of flcDNA examinations, the state of practice in France and abroad, discussions with the working group and contributions from the parties stakeholders ».
[2] The HAS indicates that the list of conditions for which identification is recommended “ will have to be reviewed based on the data that will be made available on the consequences of the different chromosomal anomalies and on the performance of flcDNA examinations ».
[3] Any pregnant woman whose combined first trimester examination (measurement of nuchal translucency and dosage of serum markers) shows a risk of Down syndrome of between 1/1,000 and 1/51. The HAS also recommends extending the indications for NIPT to patients with “ history of pregnancy with aneuploidy, if one of the parents carries a Robertsonian translocation involving chromosome 13 and in the case of a profile of maternal serum markers from the first trimester suggestive of trisomy 13 or 18 ».
[4] Karyotype, that is to say the analysis of the fetal chromosomes, is the only way to establish a diagnosis of Down syndrome (and not simple screening). However, the examination to carry it out, amniocentesis, is risky, particularly miscarriages, because the membrane surrounding the fetus is perforated.
