Interstitial pregnancy is an unusual and potentially life-threatening form of ectopic pregnancy, accounting for approximately 1-6% of all ectopic pregnancies, with a maternal mortality rate of 2-2.5%. Implantation happens in the proximal portion of the fallopian tube as it passes through the myometrium. The resolution of interstitial pregnancy after medical treatment should be assessed by a decline in serum β-hCG, which occurs in about 85-90% of cases. Nonetheless, its effectiveness and consequences have been presented through case reports and case series. However, few cases of interstitial pregnancies treated totally medically with the use of methotrexate and mifepristone have been presented in the literature. Complications of this medical treatments have also never been reviewed before. In the present manuscript, we present a case of interstitial pregnancy treated with methotrexate and mifepristone. The patient after treatment developed a uterine arteriovenous malformation, treated with uterine artery embolization. Furthermore, we performed a systematic review of the literature using Scopus, PubMed and Google Scholar. A total of 186 papers were found, and 7 papers which included 10 cases were assessed for eligibility. The systemic medical treatment with the use of methotrexate and mifepristone was effective in 7 of the 10 cases. Two cases of hemoperitoneum following combined methotrexate and mifepristone treatment were reported. The applicability of this medical conservative treatment should be tailored to the patient, taking into account their obstetric history, gestational age at diagnosis and desire for future pregnancies. Complete resolution after this treatment was achieved in most of the cases reported without major complications. The appearance of uterine arteriovenous malformation can be managed conservatively, and we propose uterine artery embolization as an effective treatment of this rare complication.
Keywords: complications; ectopic pregnancy; interstitial pregnancy; medical treatment; methotrexate; mifepristone.