TY - CHAP M1 - Book, Section TI - Transvaginal Sonography of Ectopic Pregnancy A1 - Fleischer, Arthur C. A1 - Desai, Aditi A. A1 - New, Melinda A1 - Kanter, Jessica A1 - Diamond, Michael P. A2 - Fleischer, Arthur C. A2 - Abramowicz, Jacques S. A2 - Gonçalves, Luis F. A2 - Manning, Frank A. A2 - Monteagudo, Ana A2 - Timor, Ilan E. A2 - Toy, Eugene C. Y1 - 2017 N1 - T2 - Fleischer's Sonography in Obstetrics and Gynecology: Textbook and Teaching Cases, 8e AB - Key TermsEctopic pregnancy: a gestational sac located outside of the uterine lumen. The most common location is within the ampullary segment of the fallopian tube (tubal); other locations include: interstitial, cornual, cervical, within a C-section scar (“scar ectopic”), intra-abdominal, or intraovarian.Pregnancy of “unknown location”: pregnancy whose location (intra- or extrauterine) cannot be determined sonographically. Short interval (3-5 day) follow-up sonography is highly recommended.Concept of “discriminatory zone”: β-hCG value above which evidence of an early intrauterine pregnancy should always or reliably be seen on transvaginal sonography. This concept, previously thought to be of major diagnostic value, has now been shown to be of limited value.Doubling time: expected time interval when the β-hCG level doubles in a normal early intrauterine pregnancy. Typically, the expected normal increase of hCG is greater than or equal to 50% in 48 hours. It should be noted, however, that there is a fairly large range of normal, physiologic values. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/12/11 UR - obgyn.mhmedical.com/content.aspx?aid=1151031096 ER -