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.