title: Letter: Aetiology of anencephaly and spina bifida.
mesh_terms: D000022:Abortion, Spontaneous / Q000150:complications; D000757:Anencephaly / Q000209:etiology*; D001722:Birth Order; D005260:Female; D006801:Humans; D011247:Pregnancy; D016135:Spinal Dysraphism / Q000209:etiology*