Successful pregnancy and term delivery after treatment of unicornuate uterus with non-communicating rudimentary horn pregnancy with local methotrexate injection followed by laparoscopic resection: a case report and literature review

BACKGROUND: Pregnancy in a rudimentary horn is an extremely rare type of ectopic pregnancy. A rudimentary uterine horn pregnancy is associated with a risk of spontaneous rupture and bleeding during surgery due to the increased uterine blood flow. Recent advances in imaging modalities have enabled laparoscopic surgery to be performed in cases without rupture in the early stages of pregnancy. However, there are few reports of successful pregnancies and deliveries after treatment of rudimentary horn pregnancies. We report the successful management of a case of non-communicating rudimentary horn pregnancy by local injection of methotrexate followed by complete laparoscopic excision along with a review of the literature. CASE PRESENTATION: The patient was a 29-year-old Japanese woman, gravida 2, nullipara. She was diagnosed with a left unicornuate uterus with a right non-communicating rudimentary horn on hysterosalpingography and magnetic resonance imaging. A gestational sac with a heartbeat was observed in the right rudimentary uterine horn at 6 weeks of gestation. A diagnosis of ectopic pregnancy in a non-communicating rudimentary horn was made. Color Doppler detected multiple blood flow signals around the gestational sac, which were clearly increased compared to the left unicornuate uterus. Her serum human chorionic gonadotropin level was 104,619 mIU/ml. A 100 mg methotrexate injection into the gestational sac was administered, and laparoscopic surgery was performed on day 48 after the methotrexate treatment. The right rudimentary horn and fallopian tube were successfully excised with minimal bleeding. A spontaneous normal pregnancy was established 6 months after the surgery. The pregnancy was uneventful, and a baby girl was born by elective cesarean section at 38w0d. CONCLUSION: Combined local methotrexate injection and laparoscopic surgery are safe treatment options for patients with a unicornuate uterus with a non-communicating rudimentary horn pregnancy.