Preconceptional prediction of twin pregnancies.
D000017:ABO Blood-Group System; D000328:Adult; D001723:Birth Rate; D001835:Body Weight; D010064:Embryo Implantation; D005260:Female; D005298:Fertility / Q000187:drug effects; D006801:Humans; D008423:Maternal Age; D008598:Menstruation; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012306:Risk; D013997:Time Factors; D014427:Twins
D000017:ABO Blood-Group System