It Is Worthwhile to Cryopreserve Metaphase I Oocytes for Patients With Oocytes Cryopreservation: A Live Birth Case Report

In controlled ovarian hyperstimulation (COH) cycles, many immature oocytes are retrieved and are typically discarded. Our aim is to demonstrate a case of live birth achieved through in vitro maturation (IVM) after thawing of a metaphase I (MI) oocyte in a patient with elective oocyte cryopreservation. A 36-year-old woman underwent elective oocyte cryopreservation in 2021, retrieving 28 oocytes. In 2023, 12 oocytes were thawed, with only four at metaphase II (MII) oocytes. Rescue IVM was performed on the remaining eight MI oocytes, successfully maturing five to MII. Intracytoplasmic sperm injection (ICSI) resulted in four two pronuclei and two day-five blastocysts, graded 3AA and early blastocyst - both derived from MI oocytes that matured to MII. The 3AA blastocyst was transferred in 2023, leading to the birth of a healthy male infant weighing 3580 g. This case underscores the developmental potential of immature oocytes in patients undergoing elective oocyte cryopreservation and suggests rescue IVM may serve as a valuable strategy to improve reproductive outcomes.