The Endomyometrial Thickness Measurement for Abnormal Implantation Evaluation by Pelvic Sonography

Emergency physicians, obstetrician‐gynecologists, and other medical specialists use pelvic sonography when caring for patients presenting with early pregnancy‐related symptoms. A thin endomyometrial mantle and eccentric placement of a gestational sac should raise the suspicion for an abnormally implanted pregnancy. In such cases, an interstitial ectopic pregnancy or a cornual pregnancy, two clinically distinct entities, must be considered. This article reviews the literature and guidelines on the sonographic measurement of the endomyometrial mantle as a criterion for determining a pregnancy at risk for an abnormal implantation location. We sought to clarify the history and evolution of this measurement to determine what should be considered an abnormal measurement and to understand its diagnostic utility and management implications for the clinician using sonography.