Significance of isolated yolk sac visualised by ultrasonography.
D000030:Abortion, Missed / Q000175:diagnosis; D004622:Embryo, Mammalian / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D011247:Pregnancy; D014463:Ultrasonography; D015017:Yolk Sac / Q000033:anatomy & histology*