The part of the Fallopian tube that is located in the uterine wall and connects the remainder of the tube to the endometrial cavity is called its "interstitial" part, hence the term "interstitial pregnancy"; it has a length of 1–2 cm and a width of 0.7 cm.

[4] Early diagnosis is important and today facilitated by the use of sonography and the quantitative human chorionic gonadotropin (hCG) assay.

[2] Cases that are not diagnosed until surgery show an asymmetrical bulge in the upper corner of the uterus.

[1] Because of the vascularity of the interstitial region particularly during pregnancy, blood loss during surgery may be substantial.

Postoperatively, patients with conservative surgical therapy are at risk for development of a persistent ectopic pregnancy due to the presence of deeply embedded surviving trophoblastic tissue; thus, monitoring of hCG levels is indicated until they become undetectable.

[7] Selective uterine artery embolization has been successfully performed to treat interstitial pregnancies.

[10] With the growing use of assisted reproductive technologies, the incidence of interstitial pregnancy is rising.