A heterotopic pregnancy is the simultaneous presence of an intrauterine pregnancy and an ectopic pregnancy, most commonly in a fallopian tube. Once considered extremely rare in natural conception, occurring in approximately 1 in 30,000 pregnancies, it has become more common with the use of assisted reproductive technologies, where the incidence can be as high as 1 in 100. On ultrasound, the intrauterine pregnancy may be clearly visible, but the coexisting ectopic pregnancy can be easily missed if the sonographer does not systematically evaluate the adnexa. This diagnosis is critical because the ectopic pregnancy can rupture and threaten the mother’s life while the intrauterine pregnancy continues.
Sonography Term