Prenatal screening and diagnosis for Down syndrome in the Northern Netherlands :developments and trends for the period 1981-2013

Baardman, R. (Rosalie) (2016) Prenatal screening and diagnosis for Down syndrome in the Northern Netherlands :developments and trends for the period 1981-2013. thesis, Medicine.

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Abstract

Introduction – During the study period, two major changes occurred that influenced the number of pregnancies diagnosed with Down syndrome in the Netherlands. First was the considerable increase in maternal age, which is a well-known risk factor for the development of Down syndrome. Second was the increase in possibilities of prenatal screening and (invasive) prenatal diagnosis for Down syndrome. When prenatal screening indicates an increased risk for a pregnancy complicated with Down syndrome, a pregnant woman is eligible for prenatal diagnosis. There are two forms of prenatal diagnosis to determine if a pregnancy is complicated with Down syndrome: amniocentesis since 1974 and chorionic villus sampling since 1984. In the early years of the study period, the major indication for prenatal diagnosis was a maternal age of 36 years or older. Since 1991 the triple test is available; a prenatal screening test of maternal serum to indicate the risk of a pregnant woman for a pregnancy with Down syndrome. Since 2007 a national prenatal screening program is implemented in the Netherlands, in which the combined test and a structural anomaly scan are offered to all pregnant women. From April 2014 a trial study is conducted in the Netherlands, with the offer of a non-invasive prenatal screening test to pregnant women with an increased risk for Down syndrome. The non-invasive prenatal test shows good results and has caused great expectations for the future of prenatal screening and –diagnosis for Down syndrome. Purpose - This study gives an overview of the developments and trends of prenatal screening and diagnosis for Down syndrome in the Northern Netherlands during the period 1981-2013, based on the EUROCAT-NNL database. Methods – The study included all cases with an ICD-code of 758.0 or Q90.0 for Down syndrome with a date of delivery or termination of the pregnancy between January 1st 1981 and December 31 2013. The cases should be registered at EUROCAT-NNL before September 14th 2015 for the inclusion in this study. Trends were analysed for prevalence rates, maternal age, prenatal screening and –diagnosis and pregnancy outcome. Results – In the period 1981-2013, 876 cases with Down syndrome were registered at EUROCAT-NNL, resulting in a total birth prevalence of 16,0 per 10.000 births. The total birth prevalence of Down syndrome increased and the live birth prevalence slightly decreased during the study period. In our study population, median maternal age increased from 30,0 in 1981 to 35,0 in 2013 and the proportion of births to mothers ≥ 35 years of age has risen from 25,0% to 52,6% during the study period. The proportion of pregnancies in which Down syndrome was prenatally detected and diagnosed, increased. The proportion of pregnancies resulting in termination also increased. Conclusion – The increase in the total birth prevalence may be attributed to the increase

Item Type:	Thesis (Thesis)
Supervisor name:	Supervisors: and Walle, mw dr. H.E.K. de and Bakker, mw dr. M.K. and Department: Genetics
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:39
Last Modified:	25 Jun 2020 10:39
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/55

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