The usefulness of gestational sac and placental sonographic morphology in differentiating between second-trimester tubal and abdominal pregnancy: case report and a review of literature.

Second-trimester tubal pregnancy is rarely encountered and published cases are limited. There are no established sonographic criteria to differentiate it from abdominal pregnancy; however, differences in their medical management make this distinction important. We report a case of a 14-week 5-day tubal pregnancy that presented near rupture. Sonography demonstrated many overlapping features with abdominal pregnancy. In addition, the extrauterine gestational sac was rounded and well defined and the placenta was crescent-shaped. We propose that these sonographic features represent a second-trimester tubal pregnancy rather than an abdominal pregnancy.