Urgent fertility preservation following second trimester termination in a patient with pregnancy-associated colorectal cancer: a case report and literature review.

We report a case of fertility preservation using random-start controlled ovarian stimulation and embryo cryopreservation in a patient with a recent second trimester termination. A 32-year-old patient at 17 weeks of gestation was diagnosed with advanced colorectal cancer after presenting with hematochezia and acute blood loss anemia. To initiate urgent chemotherapy, the patient underwent an elective termination at 18-week gestation. Random-start controlled ovarian stimulation (COS) was initiated seven days later using a gonadotropin-releasing hormone antagonist protocol. Despite a β-human chorionic gonadotropin level of 52.4 mIU/mL, ovarian stimulation was started. Nineteen oocytes were retrieved after 10 days of ovarian stimulation, of which 15 were mature. Eleven mature oocytes fertilized successfully using intracytoplasmic sperm injection. All 11 embryos developed into the blastocyst stage and underwent biopsy for preimplantation genetic testing for aneuploidy screening. Five blastocysts were found to be euploid. The patient subsequently initiated chemotherapy seven days after her oocyte retrieval. This case highlights the feasibility of random-start COS and embryo cryopreservation for fertility preservation immediately after a second trimester termination in a patient with newly diagnosed colorectal cancer.