Challenges in prenatal screening and diagnosis in the Netherlands
|PhD ceremony:||Ms M. (Merel) Bakker|
|When:||February 06, 2017|
|Supervisor:||prof. dr. C.M. (Katia) Bilardo|
|Co-supervisor:||dr. E. Birnie|
|Where:||Academy building RUG|
|Faculty:||Medical Sciences / UMCG|
The Dutch prenatal screenings program consists of the combined test (CT) and the 20 week anomaly scan. All pregnant women are informed about prenatal screening, but the uptake of the CT is low, especially among younger women. The CT is based on the measurement of the nuchal translucency (NT), maternal age and serum markers and has a detection rate around 90% for a false positive rate of 5% for trisomy 21, 18 and 13. Measurement of the NT is performed by certified sonographers, but still remains difficult to perform. Semi-automated measurement methods were developed to assist measurement, but these do not appear to have much added value for well-trained operators.
Once an increased risk or increased NT is found, women are counselled on the possibility of prenatal diagnostics. When performed by experienced operators the pregnancy losses associated with prenatal diagnostics are lower than previously reported. An increased NT is much more than just a marker for trisomy 21, 18 or 13. It is associated with a long and still growing list of genetic syndromes associated, the most frequently reported being the Noonan syndrome (NS). When specific prenatal ultrasound findings for NS are present, targeted DNA-analysis is indicated.
It may well be that the first trimester assessment will lose its character of primarily screening for chromosomal anomalies and become the first and most important moment of a general risk assessment in pregnancy. This new role of the first trimester assessment could change the model of care importantly.