Interstitial ectopic pregnancy presenting after failed termination of pregnancy

Sonographic diagnosis of an interstitial pregnancy in an asymptomatic patient at 7 weeks' gestation

An interstitial pregnancy is an ectopic pregnancy located within the proximal intramural segment of the Fallopian tube traversing the myometrium. This type of ectopic pregnancy is relatively rare, occurring in approximately 1%-3% of all ectopic pregnancies. Given the myometrial mantle surrounding the gestational sac, which is considerably thicker than in other tubal pregnancies, patients with interstitial pregnancies classically manifest symptoms later in gestation. Thus, there is an increased risk of life-threatening intraperitoneal hemorrhage upon rupture of the myometrium encompassing the pregnancy. We present an unusual case of early sonographic diagnosis of an interstitial pregnancy in an asymptomatic patient at 7 and 3/7 weeks’ gestation, discuss predisposing factors, hallmarks of sonographic diagnosis, and review the literature regarding available clinical management modalities. With the increasing application of point of care ultrasound (POCUS) by emergency room physicians and other providers in outpatient facilities, our case emphasizes both the importance of correct sonographic identification of interstitial pregnancy and the clinical importance of uniform early first-trimester sonography, preferably no later than 7-8 weeks’ gestation.

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.