Mistakes in estimation of duration of pregnancy.
D000328:Adult; D002584:Cervix Uteri / Q000033:anatomy & histology; D005314:Embryonic and Fetal Development; D005260:Female; D005333:Fetus / Q000000981:diagnostic imaging; D005865:Gestational Age; D006801:Humans; D008598:Menstruation; D011247:Pregnancy; D011273:Pregnancy, Prolonged; D011859:Radiography