[Prevalence of neural tube defects in Asturias (Spain): impact of prenatal diagnosis].

OBJECTIVE

To describe the frequency and prevalence trend for neural tube defects (NTD) (anencephaly, spina bifida and encephalocele) in Asturias (Spain), as well as the impact of prenatal diagnosis programs.

METHODS

All cases of NTD in births and induced abortions were studied, using data from the Registry of Congenital Defects of Asturias for 1990-2004. Total and birth prevalence rates were calculated.

RESULTS

The prevalence of NTD for 1990-2004 was 12.2 per 10,000 births (5.9 anencephaly, 5.0 spina bifida and 1.3 encephalocele) and showed a slightly decreasing trend due to a significant decline in spina bifida prevalence. The prevalence of anencephaly and encephalocele remained stable. The percentage of induced abortions after prenatal diagnosis among all NTD was 88% (anencephaly 96.7%, spina bifida 80% and encephalocele 84.6%), leading to a very low birth prevalence (1.4 per 10,000) for the entire period.

CONCLUSIONS

The total prevalence of spina bifida has decreased in the last 15 years in Asturias. Secondary prevention through prenatal diagnosis and interruption of affected pregnancies have resulted in a marked decrease in NTD at birth. The recommendation of periconceptional use of folic acid seems not to have achieved the desired effect.