We report a clinical analysis of 327 cases of Spina Bifida and 102 cases of Anencephaly in Brittany. Maternal age, parity, birth weight are not different from random population. Male rate is 0.40 for Anencephaly and 0.50 for Spina Bifida. The study of pregnancies shows an increased frequency of hydramnios during anencephaly pregnancies (0.34) and high rate of abnormalities during the pregnancy of Spina Bifida (0.34) or Anencephaly (0.86). Four mothers of Spina Bifida were taking valproic acid. Thirty children (0.07) had other malformations.