Transvaginal sonographic diagnosis of live monochorionic twin ectopic pregnancy

Ectopic pregnancy is a leading cause of pregnancy-related deaths; its incidence has progressively increased in recent years. Spontaneous twin ectopic pregnancy, however, is extremely rare. Among more than 100 reported cases of twin tubal pregnancies, only 5 cases in which fetal cardiac motion has been visualized in both embryos have been reported. We describe an additional case of a live monochorionic twin ectopic pregnancy in a patient with no predisposing factor. With transabdominal sonography, we initially diagnosed a single ectopic pregnancy, visualized as an ill-defined mass in the left adnexa. However, with transvaginal sonography, we determined the left adnexal mass to contain a single monochorionic gestational sac with 2 embryos, each with cardiac motion. These findings were confirmed with color Doppler sonography and at laparotomy. The introduction of high-resolution transvaginal sonography has resulted in the earlier diagnosis of ectopic pregnancy and has contributed to a recent decrease in the maternal mortality and morbidity associated with this condition.