A study of some maternal factors associated with twinning.
D000328:Adult; D001722:Birth Order; D005260:Female; D005313:Fetal Death / Q000453:epidemiology; D006801:Humans; D007194:India; D007226:Infant Mortality; D007231:Infant, Newborn; D008423:Maternal Age; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014427:Twins