Combining fertility preservation procedures to spread the eggs across different baskets: a feasibility study

STUDY QUESTION: What is the reproductive potential following combinations of ovarian stimulation, IVM and ovarian tissue cryopreservation (OTC) in female patients seeking fertility preservation (FP)? SUMMARY ANSWER: In selected patients, combining different FP procedures is a feasible approach and reproductive outcomes after FP in patients who return to attempt pregnancy are promising. WHAT IS KNOWN ALREADY: FP is increasingly performed in fertility clinics but an algorithm to select the most suitable FP procedure according to patient characteristics and available timeframe is currently lacking. Vitrification of mature oocytes (OV) and OTC are most commonly performed, although in some clinical scenarios a combination of procedures including IVM, to spread the sources of gametes, may be considered in order to enhance reproductive options for the future. STUDY DESIGN, SIZE, DURATION: Retrospective, observational study in a university-based, tertiary fertility centre involving all female patients who underwent urgent medical FP between January 2012 and December 2018. Descriptive analysis of various FP procedures, either stand-alone or combined, was performed, and reproductive outcomes of patients who attempted pregnancy in the follow-up period were recorded. PARTICIPANTS/MATERIALS, SETTING, METHODS: In total, 207 patients underwent medical FP. Patient-tailored strategies and procedures were selected after multidisciplinary discussion. When deemed feasible, FP procedures were combined to cryopreserve different types of reproductive tissue for future use. The main primary outcome measure was the number of mature oocytes. Live birth rates were evaluated in patients who returned for reproductive treatment. MAIN RESULTS AND THE ROLE OF CHANCE: Among patients seeking FP, 95/207 (46%) had breast cancer, 43/207 (21%) had haematological malignancies and 31/207 (15%) had a gynaecological tumour. Mean +/- SD age was 27.0 +/- 8.3 years. Eighty-five (41.1%) patients underwent controlled ovarian stimulation (COS), resulting in 10.8 +/- 7.1 metaphase II (MII) oocytes for vitrification. Eleven (5.3%) patients had multiple COS cycles. Transvaginal oocyte retrieval for IVM was performed in 17 (8.2%) patients, yielding 9.2 +/- 10.1 MII oocytes. Thirty-four (16.4%) patients underwent OTC combined with IVM of oocytes retrieved from ovarian tissue 'ex vivo' (OTO-IVM), yielding 4.0 +/- 4.3 MII oocytes in addition to ovarian fragments. Seventeen (8.2%) patients had OTC combined with OTO-IVM and transvaginal retrieval of oocytes for IVM from the contralateral ovary, resulting in 13.5 +/- 9.7 MII oocytes. In 13 (6.3%) patients, OTC with OTO-IVM was followed by controlled stimulation of the contralateral ovary, yielding 11.3 +/- 6.6 MII oocytes in total. During the timeframe of the study, 31/207 (15%) patients have returned to the fertility clinic with a desire for pregnancy. Of those, 12 (38.7%) patients had preserved ovarian function and underwent ART treatment with fresh oocytes, resulting in nine (75%) livebirth. The remaining 19 (61.3%) patients requested warming of their cryopreserved material because of ovarian insufficiency. Of those, eight (42.1%) patients had a livebirth, of whom three after OTO-IVM. To date, 5/207 patients (2.4%) achieved an ongoing pregnancy or livebirth after spontaneous conception. LIMITATIONS, REASONS FOR CAUTION: Our FP programme is based on a patient-tailored approach rather than based on an efficiency-driven algorithm. The data presented are descriptive, which precludes firm conclusions. WIDER IMPLICATIONS OF THE FINDINGS: Combining different FP procedures is likely to enhance the reproductive fitness of patients undergoing gonadotoxic treatment but further follow-up studies are needed to confirm this.