Oocyte in-vitro maturation primed with letrozole-HCG versus FSH-HCG in women with oocyte maturation abnormalities: a retrospective study

RESEARCH QUESTION

Are there differences between in-vitro maturation (IVM) primed with letrozole-human chorionic gonadotrophin (HCG) and IVM primed with FSH-HCG in women with oocyte maturation abnormalities (OMAs), defined as at least two failed IVF cycles where immature oocytes were retrieved?

DESIGN

This retrospective study was conducted at a private fertility clinic from January 2009 to April 2023. The final analysis included 75 women in Group 1 (IVM primed with FSH-HCG) and 52 women in Group 2 (IVM primed with letrozole-HCG).

RESULTS

A significantly higher median number of oocytes was obtained in Group 1 compared with Group 2 {9 [interquartile range (IQR) 1-5] versus 5 (IQR 1-18); P < 0.001}. However, no differences in oocyte maturation stage at collection were found between the groups (P > 0.05). At the end of IVM, Group 1 had 73/666 mature oocytes and Group 2 had 106/322 mature oocytes, and the median metaphase II oocyte rate per patient was higher in Group 2 [33.3% (IQR 66.7-100.0%) versus 0.0% (IQR 0.0-22.2%); P < 0.001]. Moreover, Group 2 demonstrated a higher median fertilization rate [66.7% (IQR 50.0-100.0%) versus 50.0% (IQR 0.0-66.7%); P = 0.027]. Group 2 had a higher proportion of Grade 2 embryos (58.5% versus 6.3%), and Group 1 had a higher proportion of Grade 3 embryos (93.8% vs 24.4%; P < 0.001). Notably, all pregnancies obtained in the study were in Group 2 (5 versus 0; P = 0.042).

CONCLUSIONS

IVM primed with letrozole-HCG in women with prior failed IVF cycles due to OMAs may result in mature oocytes, clinical pregnancies and live births. The effectiveness of letrozole priming for the subtypes of OMAs needs further investigation, with studies including greater numbers of cases.

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&lt;OPU. After menstruation, letrozole 5mg days 3–7; SChCG 250ug when follicles=12 mm 38 hours&lt;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

Can in vitro maturation overcome cycles with repeated oocyte maturation arrest? A classification system for maturation arrest and a cohort study

OBJECTIVE

To investigate the role of gonadotropin-stimulated and human chorionic gonadotropin (hCG) -primed in vitro oocyte maturation (IVM) in cases of repeated in vitro fertilization (IVF) failure due to various forms of oocyte maturation arrest (OMA).

METHODS

Retrospective cohort study.

RESULTS

In all, 63 women with IVF failure due to OMA were evaluated in this study. According to the Hatirnaz & Dahan classification, 11 (17.5%) women were OMA type 1, 22 (34.9%) were OMA type 2, 0 were OMA type 3, 11 (17.5%) were OMA type 4, and 19 women were OMA type 5 (30.1%). Fewer oocytes were retrieved in the IVM than in the IVF cycles. No embryos were produced from oocytes collected in the IVM cycles of women with OMA types 1, 2, and 4. In the OMA type 5 group, 9 (47.4%) day 2 embryos and 6 (31.6%) day 3 embryos were obtained. The difference between the groups was statistically significant (P = 0.001, P = 0.002, respectively). Single day 3 embryo transfer was performed for the six patients with OMA type 5 but no clinical pregnancies occurred.

CONCLUSIONS

Follicle-stimulating hormone-stimulated and hCG-primed IVM does not improve oocyte maturation, developmental potential, or pregnancy rates of women with OMA. Future studies directed to re-establishing normal cytoskeletal architecture and machinery, and resumption of meiosis may be beneficial for obtaining mature oocytes.