Ectopic pregnancy sonography

Ectopic pregnancy sonography

The ultrasound exam should be performed both transabdominal and transvaginally. The transabdominal component provides a wider overview of the abdomen, whereas a transvaginal scan is important for diagnostic sensitivity.

Positive sonographic findings include:

• uterus

  • an empty uterine cavity or no evidence of an intrauterine pregnancy

    • an exception to this is a rare heterotopic pregnancy

  • pseudogestational sac or decidual cyst: may be seen in 10-20% of ectopic pregnancies

    • evidence suggests that one should not initiate treatment for ectopic pregnancy in a haemodynamically stable woman on the basis of a single hCG value 11

  • decidual cast

  • thick echogenic endometrium

• tube and ovary

  • simple adnexal cyst: 10% chance of an ectopic

  • complex extra-adnexal cyst/mass: 95% chance of a tubal ectopic (if no intrauterine pregnancy)

    • an intra-adnexal cyst/mass is more likely to be a corpus luteum

  • solid hyperechoic mass is possible but non-specific

  • tubal ring sign

    • 95% chance of a tubal ectopic if seen

    • described in 49% of ectopics and in 68% of unruptured ectopics

  • ring of fire sign: can be seen on color Doppler in a tubal ectopic, but can also be seen in a corpus luteum

  • an absence of color Doppler flow does not exclude an ectopic

  • live extrauterine pregnancy (i.e. extra-uterine fetal cardiac activity): 100% specific, but only seen in a minority of cases