title: A study of two variables from the birth certificates of twins: mortality and maternal reproductive history.
mesh_terms: D001719:Birth Certificates; D001722:Birth Order; D003644:Death Certificates; D005260:Female; D005313:Fetal Death; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D011336:Probability; D012737:Sex Factors; D014427:Twins