P–709 Dual stimulation in-vitro-maturation (Duostim IVM) for overcoming oocyte maturation arrest, resulting in embryo transfer and livebirth

Study question

Does luteal phase followed by follicular phase letrozole priming and dual oocyte retrieval for in-vitro maturation (IVM) overcome oocyte maturation arrest (OMA)?

Summary answer

Oocyte maturation, fertilization,embryo cryopreservation and livebirth can be achieved with letrozole priming IVM in rare cases of OMA.

What is known already

OMA is an intractable problem resulting in only immature oocytes being collected and to date no succesful treatment exists. Attempts to mature oocytes collected in stimulated IVF cycles with OMA have so far failed. Cases with OMA can be due to intrinsic oocyte defects, intrafollicular factors or resistance to stimulation.

Study design, size, duration

Six women with OMA in ≥ 2 prior stimulated IVF cycles were treated between March 2019 and December 2020.

Participants/materials, setting, methods

Participants had total of 18 (range 2 - 6) prior IVF cycles yielding only 166 immature oocytes. Letrozole 5mg was given days 15–18 of ovulatory cycle; SC decapeptyl 0.1mg trigger given at follicles 12 mm, 38 hours<OPU. After menstruation, letrozole 5mg days 3–7; SChCG 250ug when follicles=12 mm 38 hours<OPU. After in-vitro-maturation oocytes reaching MII were fertilized. Embryos from luteal collection were frozen and fresh embryo transfer was attempted after follicular phase collection.

Main results and the role of chance

Six women underwent DuoStim IVM, median (quartiles) 3.5 (0 - 9) GV and 0.5 (0 - 2) MI oocytes were collected from luteal phase OC and 0 (0 - 0) GV and 2(0 – 4.5) MI oocytes were collected from follicular phase OC. They had a total of 166 immature oocytes collected in prior IVF cycles. There were no MII oocytes at the time of collection in any cycles.0 (0 – 3.5) oocytes matured from luteal phase OC and 1 (0 – 4) from follicular phase OC. 0 (0 – 1.5) embryos were available from luteal phase and 0 (0 - 2) from follicular phase OC.Two subjects (29 and 33 years old) underwent fresh DET and the 29 year old with 2 previous failed IVF cycles achieved a livebirth (50% per ET and 16.7% per started cycle). None of the women who did not have an embryo for fresh transfer from the follicular phase collection had an embryo from the luteal phase collection. The same 29 year old has 2 luteal phase and 2 more follicular phase embryos vitrified.

Limitations, reasons for caution

OMA is a rare condition with a variety of etiologies. Different etiologies can require different managements.

Wider implications of the findings: It may be possible to overcome OMA with letrozole IVM in rare cases. This case is the first recorded live birth. The value of dual stimulation overcoming OMA remains uncertain.

Trial registration number

This study is approved by the local ethical commitee of Medicana Samsun International Hospital by a Grant number of 02/05.02.2020: registration is not required due to retrospective status