Scripties UMCG - Rijksuniversiteit Groningen
English | Nederlands

De toegevoegde waarde de nekplooi meting in vergelijking met niet invasieve prenatale screening

(2016) Bosschieter, P.F.N.

Background and Objectives The Dutch Ministry of Health, Welfare and Sport is expected to take a decision on short term on the provision of Non-Invasive Prenatal Testing (NIPT) in the 10th week for all pregnancies. Herewith the current combined testing in the first trimester, with the Nuchal Translucency (NT) measurement as part, may completely disappear. However, it is confirmed that the predictive value of increased NT goes further than only diagnosing Trisomy 13, 18 and 21. The aim of this study is to identify on a national level what exactly the added value of NT measurement is, by discovering how many and which abnormalities can be detected by an NT measurement. That way, it can be mapped out which consequences the disappearance of combined testing will have; in other words which abnormalities might be delayed or not at all be diagnosed. Methods From the databases of four academic hospitals 16003 pregnancies were selected, whereby combined testing was performed in the first trimester of the pregnancy during the period 01-01-2010 up to and including 31-12-2015. Pre- and postnatal information, with emphasis on results of karyotyping, advanced ultrasound examination, post-mortem results and consultations by the clinical geneticist, was retrospectively collected and analyzed of all pregnancies with an increased NT (>95th percentile). Results 1390 fetuses (8.7%) had an increased NT; nearly half of them had an abnormality. 535 were diagnosed with Trisomy 13,18 or 21 and thus were potentially detectable by NIPT. 271 had a structural, genetic or rare chromosomal abnormality which was not detectable by NIPT. If NIPT will replace combined testing as screening method in the first trimester of the pregnancy, the consequence will be that the opportunity of early warning and diagnosing will be missed for these abnormalities. Conclusion Ideally both (screening)tests should be used in parallel. That way Trisomy 13, 18 and 21 can be diagnosed with high sensitivity and specificity and invasive procedures are less needed. On the other hand, using the NT measurement, adequate counseling and early diagnosis of severe abnormities can be accomplished, such preventing unpleasant surprises at the 20th week of pregnancy. Also in case of severe anomalies an earlier pregnancy termination is less traumatic for the mother. In addition, the missed cases of mainly Trisomy 13 and 18, where NIPT is less accurate, and where the NT is often thickened, yet can be diagnosed early.

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