Clinical experience with single-nucleotide polymorphism-based non-invasive prenatal screening for 22q11.2 deletion syndrome.

OBJECTIVES: To evaluate the performance of a single-nucleotide polymorphism (SNP)-based non-invasive prenatal test (NIPT) for the detection of fetal 22q11.2 deletion syndrome in clinical practice, assess clinical follow-up and review patient choices for women with high-risk results. METHODS: In this study, 21 948 samples were submitted for screening for 22q11.2 deletion syndrome using a SNP-based NIPT and subsequently evaluated. Follow-up was conducted for all cases with a high-risk result. RESULTS: Ninety-five cases were reported as high risk for fetal 22q11.2 deletion. Diagnostic testing results were available for 61 (64.2%) cases, which confirmed 11 (18.0%) true positives and identified 50 (82.0%) false positives, resulting in a positive predictive value (PPV) of 18.0%. Information regarding invasive testing was available for 84 (88.4%) high-risk cases: 57.1% (48/84) had invasive testing and 42.9% (36/84) did not. Ultrasound anomalies were present in 81.8% of true-positive and 18.0% of false-positive cases. Two additional cases were high risk for a maternal 22q11.2 deletion; one was confirmed by diagnostic testing and one had a positive family history. There were three pregnancy terminations related to screening results of 22q11.2 deletion, two of which were confirmed as true positive by invasive testing. CONCLUSIONS: Clinical experience with this SNP-based non-invasive screening test for 22q11.2 deletion syndrome indicates that these deletions have a frequency of approximately 1 in 1000 in the referral population with most identifiable through this test. Use of this screening method requires the availability of counseling and other management resources for high-risk pregnancies.

[To be born without risk: searching for small maternity centres]. / Naitre sans risque: la quête des petites maternités.

In 1992, in the public sector, 18% of child deliveries took place in small maternity centres having less than 15 beds. In 1981, the percentage has fallen to 11%. In the private sector, the two proportions were respectively 30% and 11%. From the demographic point of view, the process of urbanization and the sharp decrease in the overall birth rate explain the trend. From the medical point of view, as the small maternities cannot have sophisticated equipment, the risk to the mother and the child is likely far greater than in maternities in large cities. However, there is no clear-cut empirical evidence. Moreover, the closing down of a maternity centre in a small city means loss of individual jobs, of collective prestige and the start of overall decline. Furthermore, people have a greater felling of safety with a neighboring maternity centre. In France, the subject is extremely controversial. The article shows some directions to cope with the debates.