Ectopic pregnancy.

The differential diagnosis in a pregnant patient who presents with pain and bleeding in the first trimester includes normal early pregnancy, spontaneous abortion, molar pregnancy, and ectopic pregnancy. Knowledge of the sonographic appearance of these entities is helpful at arriving at the correct diagnosis. When no intrauterine pregnancy is visualized, careful attention to the adnexa is crucial for finding an extraovarian mass, since the fallopian tube is the most common location for ectopic pregnancy. This review describes and illustrates the sonographic findings of ectopic pregnancy.