title: [20 cases of trisomy 18. Sex-ratio in relation to age of the mother].
authors.forename: B M
authors.initials: BM
authors.lastname: Le Marec
authors.forename: J C
authors.initials: JC
authors.lastname: Lair
authors.forename: J
authors.initials: J
authors.lastname: Kérisit
authors.forename: F
authors.initials: F
authors.lastname: Le Mée
authors.forename: J
authors.initials: J
authors.lastname: Sénécal
mesh_terms: D000015:Abnormalities, Multiple / Q000453:epidemiology / Q000235:genetics*; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D015897:Comorbidity; D019465:Craniofacial Abnormalities / Q000453:epidemiology / Q000235:genetics; D004314:Down Syndrome / Q000453:epidemiology / Q000235:genetics; D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology / Q000235:genetics; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D011247:Pregnancy; D012744:Sex Ratio; D013223:Statistics as Topic; D016019:Survival Analysis; D014314:Trisomy