Impact of the screening programmes

It is evident that the introduction of universal screening programmes increases the detection rate but whether this improves neonatal morbidity and mortality is controversial and depends on the abnor­malities found, the diagnostic expertise, and the availability of ter­mination of pregnancy in the population.

The two important questions to be answered when introducing ultrasound as a screening tool are the effectiveness of ultrasound in detecting the pathologies and the implications of this on the peri­natal outcome. A study published in 2005 reported on the detection rates for the specific anomalies. An overall detection rate of about 60% was reported.

Another recent study from the EUROCAT (34) database assessed prenatal screening policies and the impact on detection rates and termination of pregnancy. It looked at neural tube defects as an in­dicator of assessing the efficacy of ultrasound anomaly screening in an attempt to map the current state of prenatal screening in Europe. The study concluded that in countries with an established national screening programme for prenatal diagnosis of neural tube defects, 91% of all abnormalities were detected prenatally at a median ges­tation of 17 weeks and resulted in 84% of all affected pregnancies undergoing termination. Countries that did not have a national screening programme for fetal anomalies but did perform routine