Uterine Ectopic Pregnancies and Live Births: Systematic Review of the Literature and Concepts Underlying Favorable Outcomes

Background and Objectives: Uterine ectopic pregnancy includes uterine extraendometrial forms such as cervical, intramural, and interstitial pregnancies, whose incidence is increasing with prior uterine surgery and assisted reproduction. Unlike cesarean scar pregnancy, which is known to occasionally progress to term, the potential for these other types to continue beyond the first trimester remains poorly defined. This review evaluates reported cases carried to viability, focusing on maternal and neonatal outcomes and identifying prognostic factors influencing progression. Materials and Methods: This systematic review was conducted in accordance with PRISMA guidelines and registered in PROSPERO (CRD420251070864). Comprehensive searches of PubMed, Scopus, and Web of Science up to June 2025 identified English-language case reports of uterine ectopic pregnancies (cervical, intramural, or interstitial) resulting in live birth. Data on maternal characteristics, clinical presentation, pregnancy course, delivery outcomes, and neonatal parameters were extracted. Study quality was assessed using the Joanna Briggs Institute checklist for case reports. Results: Uterine ectopic pregnancies were frequently misdiagnosed, with definitive diagnosis established only at delivery in 85% of cases. The majority of patients presented with abdominal pain or vaginal bleeding, and maternal morbidity was considerable: two-thirds required hysterectomy, and blood transfusions were often necessary due to severe hemorrhage. Fourteen live births were reported (nine interstitial, four cervical, and one intramural). Neonatal survival was primarily dependent on gestational age at delivery, while successful continuation of pregnancy appeared favored by implantation in more distensible myometrial regions and the presence of residual endometrial tissue. Conclusions: An increased amount of endometrium and greater myometrial distensibility at the implantation site enhance the likelihood of uterine ectopic pregnancies progressing to viability. These factors should guide early diagnosis, patient counseling, and individualized management, considering gestational age, implantation type, and future fertility goals.