Sonographic detection of interstitial pregnancy.

Interstitial pregnancy is a rare form of ectopic pregnancy that carries a higher morbidity and mortality than other tubal pregnancies. The sonographic findings in 11 cases of proven interstitial pregnancy were reviewed and compared with 12 cases published thus far. An ectopic pregnancy was diagnosed in all cases, and an interstitial location was suspected in five cases preoperatively. An eccentrically located gestational sac surrounded by an asymmetric myometrial mantle and a separate empty uterine cavity with endometrial echoes were the most common findings in our cases. When an interstitial pregnancy is suspected by sonography, confirmation by laparoscopy is recommended.