Clinical analysis of 8 cases of interstitial pregnancy after embryo transfer

This study aimed to improve the diagnosis and treatment of intramural pregnancy (IMP). A retrospective analysis was conducted of 8 cases of IMP admitted between November 2016 and June 2024. Data on patients' clinical characteristics, diagnosis, treatment, and prognosis were systematically reviewed. All 8 patients experienced IMP following embryo transfer due to tubal factor infertility. Among them, 2 had adenomyosis. All patients had a history of pelvic surgery, including 4 with tubal pregnancy surgery and 2 with uterine cavity surgery. A total of 11 embryos were transferred among the 8 patients, with 8 being high-quality embryos. The fertilization methods included in vitro fertilization and intracytoplasmic sperm injection. The onset of symptoms occurred between 23 and 54 days after embryo transfer. Upon admission, none of the 8 patients exhibited obvious abdominal pain. Preoperative diagnosis included 5 cases of tubal pregnancy and 3 cases of IMP. There were no cases of uterine rupture prior to treatment. All cases were confirmed via combined hysteroscopic and laparoscopic exploration. Among the cases, 6 interstitial pregnancy lesions protruded toward the uterine serosa, 1 slightly into the uterine cavity, and 1 showed no protrusion into either the uterine cavity or the serosa. Cases with gestational lesions slightly protruding into the uterine cavity primarily underwent hysteroscopic resection of the gestational lesion, whereas lesions protruding into the uterine serosa were treated with laparoscopic resection. For cases where the lesion neither protruded into the uterine cavity nor into the serosa, ultrasound-guided local methotrexate (MTX) injection was the primary treatment approach. These cases either received or did not receive systemic MTX treatment as adjuvant therapy. After treatment for gestational lesions, no additional surgeries were performed, and serum human chorionic gonadotropin levels returned to normal within 20 to 90 days. IMP is a rare condition associated with a risk of uterine rupture. Clinical presentations are often atypical, and imaging studies are critical for early diagnosis. Treatment approaches are individualized and may involve surgical resection of gestational lesions, ultrasound-guided embryonic reduction, or local/systemic administration of MTX.