Failed Intrauterine Pregnancy: What Is a Failed Pregnancy, What Is Not?CANAVAN, TIMOTHY P. MD, MScClinical Obstetrics and Gynecology: September 2017 - Volume 60 - Issue 3 - p 562–574 doi: 10.1097/GRF.0000000000000301 Advances in Ultrasound and Obstetrical Imaging Abstract Author InformationAuthors Article MetricsMetrics Pregnancy failure is defined as a lack of sonographic evidence of current or expected viability. Technologic advances in ultrasound imaging continue to redefine diagnostic criteria of pregnancy failure or success. When evaluating a pregnancy, the first step is an assessment of maternal risk factors for failure. Imaging clues such as an empty gestational sac measuring ≥25 mm or an embryo ≥7 mm without cardiac activity are reliable signs of pregnancy failure, whereas embryonic growth <1 mm/d is not. Combinations of sonographic findings can be used for a more accurate prediction of pregnancy success or failure. Division of Ultrasound, Magee Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania The author declares that there is nothing to disclose. Correspondence: Timothy P. Canavan, MD, MSc, Division of Ultrasound, Magee Womens Hospital, University of Pittsburgh, Pittsburgh, PA. E-mail: email@example.com Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.