Distinguishing between interstitial and angular pregnancies: Is there a role for saline infusion sonohysterography?

Abstract

Objective: Interstitial pregnancy occurs in the intramural segment of the Fallopian tubes, while angular pregnancy is one that is located in one of the lateral angles of the uterine cavity. The differential diagnosis and treatment of these conditions are important. We have used saline infusion sonohysterography (SIS) to help in differential diagnosis. Case report: A 36-year-old female with a case of suspected left interstitial ectopic pregnancy was admitted. Her diagnostic laparoscopy showed no tubal ectopic pregnancy, and D&C demonstrated no villi. She underwent SIS which showed a sac in the interstitial part but close to the tubal ostium. The second case involves a 21-year-old female who was 9-weeks pregnant. Ultrasonography could not differentiate between interstitial and angular pregnancy. SIS clearly demonstrated angular pregnancy with a missed abortion, and therapeutic D&C was done smoothly. Conclusion: From reviewing past literature, SIS does not appear to have any proven adverse effect on the pregnancy although it is not widely accepted. This article highlights the benefits of using SIS to aid in the differential diagnosis between the two conditions, especially in unusual cases like ours. Keywords: Saline infusion sonohysterography, Interstitial pregnancy, Angular pregnancy, Ackerman interstitial line