Oncofertility case report: live birth 10 years after oocyte in vitro maturation and zygote cryopreservation

This study aims to report a case of urgent fertility preservation in an oncological patient with collection of immature oocytes in the absence of ovarian stimulation that, through in vitro maturation (IVM), followed by ICSI and cryopreservation of zygotes resulted, 10 years later, in the live birth of a healthy baby.

In September 2008, our clinic performed IVM in a 32-year-old woman diagnosed with a ductal invasive carcinoma with positive estradiol receptors, negative progesterone receptors and positive human epidermal growth factor receptor 2. The retrieval of immature oocytes was performed in the absence of ovarian stimulation after a simple mastectomy and prior to any chemotherapy treatment. The compact cumulus-oocyte complexes (COCs) collected were placed in Lag medium for 2 h, followed by incubation in IVM medium, supplemented with heat inactivated patient serum, recombinant FSH, and recombinant LH. After 30 h in culture, cumulus cells were removed, the metaphase II oocytes were microinjected, and the zygotes obtained were cryopreserved. In 2017, the zygotes were thawed and cultured until day 3. One embryo was transferred and the other cryopreserved.

Four compact COCs were collected and subjected to IVM. Two oocytes reached metaphase II and were microinjected. Two zygotes were obtained and were cryopreserved at the two pronuclear stage. Approximately 9 years later, the two zygotes were thawed and cultured until day 3. An embryo with 10 cells was transferred and implanted, resulting in the birth of a healthy baby.

In cases where urgency to start adjuvant therapy requires immediate oocyte collection, IVM may be the only option to obtain fully competent mature oocytes allowing for effective preservation of the reproductive potential.