This attempt to ‘map’ the state of prenatal diagnosis in 18 European countries in 2004 has confirmed wide variation in the availability and type of noninvasive screening tests for Down's syndrome, in the number of ultrasound scans offered and in the legal gestational limits regarding TOPFA. This broad view of prenatal diagnosis updates a previous report describing prenatal diagnosis in different countries in Europe between 1993 and 1995.9
In 2004, the majority of countries had moved from solely offering older mothers a diagnostic test to having some form of Down's syndrome screening in place, with over half having an official country-wide policy or recommendation for first- or second-trimester screening. Having a screening policy in place had a measurable impact on prenatal detection rates for Down's syndrome; the registry areas in countries offering primarily first-trimester screening had a significantly higher detection rate than those using a mixed first or second-trimester screening policy; those with some screening but no national screening policy in place were significantly less likely to detect a Down's syndrome case prenatally. However, there are wide variations in detection rates between different countries using similar screening policies. For example, Germany and France have both first and second-trimester screening policies; yet, the prenatal detection rate of Down's syndrome in the German registry area is 63% compared with 90% for France. Some of this difference may be due to a higher proportion of older mothers in the French registry (Paris, 28% of mothers aged ≥35 years) than in the German registry area (Mainz, 22% of mothers aged ≥35 years) in the period 2002–04. In all countries where TOPFA is legal, the majority of cases of Down's syndrome detected prenatally resulted in termination of pregnancy; in most (7/10) registry areas, more than 90% of prenatally diagnosed affected pregnancies resulted in termination.
Most countries had an official, country-wide policy for routine ultrasound anomaly scanning. This study has used the prenatal detection of NTDs as an indicator for assessing the efficacy of ultrasound anomaly scanning because they are relatively common and are associated with a high prenatal detection rate.10
It may, however, be that other anomalies which are more difficult to detect prenatally would serve as better indicators of the widespread use and quality of ultrasound anomaly screening. Those countries that did not have a policy for offering routine scans had a significantly lower prenatal detection rate of NTD. One factor that may be important when termination of pregnancy is being considered is the gestational age at suspicion of fetal anomaly. Of the countries where TOPFA is legal, the country with the lowest termination rate for NTD (29% of prenatally detected cases) was the Netherlands where the median gestation at prenatal diagnosis was 31 weeks compared with 17 weeks for all countries. However, gestation at diagnosis is not the only factor; in the German registry area, 90% of NTDs were prenatally detected at a median gestation of 18 weeks and less than half (44%) of the prenatally detected cases resulted in termination of pregnancy, while in France, England and Wales and Spain, there were high detection rates (94%) and high (92–98%) termination rates.
Discussion of TOPFA and the legal gestation limit for termination causes controversy. The laws regarding TOPFA vary in their gestation limit in the different countries. This study shows that having a legal limit of less than 28 weeks of gestation for TOPFA does not have a major impact on termination rates for Down's syndrome or NTDs. This implies that a well-organised screening system should be able to ensure that most women are given choices before the fetus becomes viable.
A strength of this study is that it provides information on prenatal policies in place in whole countries rather than in centres of excellence and attempts to relate policies or lack of policies to prenatal detection rates. However, there are limitations; first, because data are only provided from areas covered by full EUROCAT registries; for some countries (e.g. Switzerland and Germany), this will only be from a small area, which is not necessarily representative of the whole country. Second, although the year 2004 has been chosen for the existence or not of a country-wide policy, data are from the years 2002–04. For one country (Denmark, where the screening policy was introduced in 2004), this may underestimate the impact of a recently introduced policy.
The existence of a national policy or recommendation for a particular screening test does not necessarily equate with the delivery of the offer of such screening to all women in all areas because of lack of resources, of information provided to women within the time frame for making an informed decision, lack of uptake or late booking.11,12
The uptake and impact of different programmes will depend on social and cultural factors as well as on the availability of different resources and laws regarding TOPFA. The absence of a national screening policy may reflect a considered decision that is itself ‘a policy’.
In this paper, we have concentrated on the two anomalies (Down's syndrome and NTDs) for which screening methods were initially developed. The existence of screening has led to difficult ‘grey areas’ in terms of what types of birth defect can now be prenatally detected and whether termination of pregnancy is an appropriate choice, for example Turner syndrome and facial clefts.13–15
There is some concern about a potentially negative effect of widespread screening on the perceptions about individuals born with birth defects and the services that might be available for their care.13,14
However, prenatal screening has opened up new possibilities to enhance the treatment and survival of liveborn children with birth defects.16,17
The situation regarding screening policies is not a static one. Some countries will have already updated their policies to achieve higher detection and lower false-positive rates. New developments in noninvasive prenatal testing based on fetal DNA in maternal blood are becoming a realistic prospect for the future.18,19
We can expect that prenatal screening policy will continue to be dynamic and that variation between countries in Europe will continue to lead to large but changing differences in prenatal detection and termination rates.