Geographical, secular and ethnic influences in anencephalus.
D000757:Anencephaly / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D002170:Canada; D005006:Ethnicity; D005060:Europe / Q000208:ethnology; D005260:Female; D005843:Geography; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D012111:Residence Characteristics; D012306:Risk