Prevalence of neural tube defects in northeastern France, 1979-1992 impact of prenatal diagnosis.

The objective of this study was to determine in total prevalence of neural tube defects (NTD) in northeastern France during 1979-1992 inclusive, the impact of prenatal diagnosis on birth prevalence. All births and termination of pregnancy affected by NTD were ascertained from multiple sources thank to our registry of congenital anomalies. In our region maternal serum alpha-fetoprotein screening is not available whereas routine ultrasonographic screening of congenital anomalies is performed in all pregnant women. Total prevalence of NTD during 1979-1992 was 10.94 per 10,000 with no upward or downward trend. The total prevalence of NTD in our region remained stable. However birth prevalence fell significantly. The fall was 100 per cent for anencephaly and 60 and 50 per cent for spina bifida and encephalocele, respectively. This decrease was obtained by routine ultrasonographic examination only and termination of pregnancy. Comparison with similar studies in other countries demonstrated that screening by maternal serum alpha-fetoprotein is needed in our region.