A Case of Pre-Existing Pregnancy During an In-Vitro Fertilization Cycle

Serum progesterone levels performed prior to oocyte pick-up is commonly used to guide embryo transfer in in-vitro fertilization (IVF) cycles, as elevated levels can negatively influence pregnancy outcomes. However, levels associated with normal pregnancies should trigger clinicians to consider alternative causes such as a pre-existing pregnancy. We report a case of a 37-year-old patient who underwent controlled ovarian hyperstimulation in a gonadotrophin-releasing hormone antagonist cycle while having an undetected early pregnancy. No oocytes were retrieved at oocyte retrieval despite adequate follicular responses. Her serum progesterone level on the day of her trigger injection was 57.8 nmol/L. She was found to have a pregnancy of unknown location, detected 3 weeks after her oocyte retrieval and was subsequently treated with systemic methotrexate.