Sonographic diagnosis of ectopic pregnancy with endovaginal probes: what really has changed?

To evaluate the impact of endovaginal (EV) sonography in the diagnosis of ectopic pregnancy, a 2 year retrospective study was performed identifying 123 at-risk patients. Of these 123 women, 19 (15.4%) had a surgically proved ectopic pregnancy, only three (15.8%) of which were visualized directly at sonography. A confident diagnosis of an intrauterine pregnancy (IUP) was made at the initial scan in 74%, which contrasts with 58% diagnosed at the first transabdominal (TA) scan in an earlier study from this laboratory, thus confirming an improvement in diagnostic ability with EV transducers. This study has failed to confirm some findings of other workers, particularly that adnexal ring-like structures are visualized frequently in the presence of an ectopic pregnancy. No adnexal rings were observed in our 19 cases. The combination of an adnexal mass and free pelvic fluid was found to correlate best with the presence of an ectopic pregnancy. This study further emphasizes that a significant proportion (26.3%) of ectopic pregnancies have a normal EV sonogram at presentation. The group failing to demonstrate an IUP and showing no evidence of an adnexal mass or pelvic fluid (i.e., a normal pelvic sonogram) carried a 1:3 risk for the presence of an ectopic pregnancy, a result that is very similar to our data published before the introduction of EV technology. We conclude that, although it provides a significant improvement and refinement in the recognition of intrauterine pregnancies, EV scanning does not permit a confident diagnosis of ectopic pregnancy in many cases.