The decidua-chorionic sac: a reliable sonographic indicator of intrauterine pregnancy prior to detection of a fetal pole.
Morphologically, the uterus in early intrauterine pregnancy, unlike ectopic pregnancy, contains both decidua and a chorionic sac. In view of this fact, a prospective study was performed to determine the accuracy of the demonstration of an intrauterine decidua-chorionic sac (DCS) in differentiating early or small intrauterine pregnancies (IUPs) without a demonstrable fetal pole from the intrauterine findings of ectopic pregnancy. The DCS was seen in 78 patients with proven IUPs and was not present in 52 consecutive patients with proven ectopic pregnancy (100 per cent accuracy). The decidua-chorionic sac is defined, and its relationships to the "double sac," double decidual sac, pseudosac, "crescent," pseudogestational sac, and the discriminatory human chorionic gonadotropin zone are discussed.
D002823:Chorion; D003656:Decidua; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000175:diagnosis*; D011446:Prospective Studies; D014463:Ultrasonography