TY - CHAP M1 - Book, Section TI - TRANSVAGINAL SONOGRAPHY OF ECTOPIC PREGNANCY A1 - Fleischer, Arthur C. A1 - Diamond, Michael P. A1 - Cartwright, Peter S. A1 - New, Melinda A2 - Fleischer, Arthur C. A2 - Toy, Eugene C. A2 - Lee, Wesley A2 - Manning, Frank A. A2 - Romero, Roberto J. Y1 - 2015 N1 - T2 - Sonography in Obstetrics and Gynecology: Principles & Practice, 7e AB - DefinitionsDiscriminatory zone: β-hCG value above which evidence of an intrauterine pregnancy should be seen on transvaginal sonography.Doubling time: Expected time interval when the β-hCG level doubles in a normal early intrauterine pregnancy. The expected normal increase of hCG is greater than or equal to 50% in 48 hours.Pregnancy of "unknown location": pregnancy whose location (intra- or extrauterine) cannot be determined sonographically. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - obgyn.mhmedical.com/content.aspx?aid=1106704245 ER -