The developmental potential of mature oocytes derived from rescue in vitro maturation

Assessing the developmental competence of oocytes matured following rescue in vitro maturation: a systematic review and meta-analysis

PURPOSE

To assess the developmental competence of oocytes matured following rescue in vitro maturation (IVM).

METHODS

PubMed, EmBASE, and SCOPUS were systematically searched for peer-reviewed original papers using relevant keywords and Medical Subject Heading terms. Study quality was assessed using the Newcastle-Ottawa Scale. Odds ratios with a 95% confidence interval were calculated by applying a random effects model. The primary outcomes were fertilization and blastulation rates. Secondary outcomes included abnormal fertilization, cleavage, euploidy, clinical pregnancy, and live-birth rates.

RESULT

Twenty-four studies were included in the meta-analysis. The oocytes matured following rescue IVM showed significantly reduced fertilization, cleavage, blastulation, and clinical pregnancy rates compared to sibling in vivo-matured oocytes. No significant differences were found for the euploidy and live-birth rates in euploid blastocyst transfer. In poor responders, a reduced fertilization rate was observed using in vitro-matured GV but not with in vitro-matured MI. A reduced cleavage rate in MI matured overnight compared to < 6 incubation hours was found.

CONCLUSION

Our results showed compromised developmental competence in oocytes matured following rescue IVM. However, in poor responders, rescue IVM could maximize the efficiency of the treatment. Notably, our data suggests using in vitro MI matured within 6 incubation hours.

CLINICAL TRIAL REGISTRATION NUMBER

CRD42023467232.

First pregnancy and live birth from ex vivo-retrieved metaphase II oocytes from a woman with bilateral ovarian carcinoma: a case report

OBJECTIVE

To report pregnancy and live birth resulting from intracytoplasmic sperm injection of ex vivo-retrieved mature oocytes from a woman with bilateral ovarian carcinoma.

DESIGN

Case report.

SETTING

Fertility clinic.

PATIENT

A 34-year-old nulliparous woman with bilateral ovarian tumor, with a risk of malignancy of 96.1% according to International Ovarian Tumor Analysis Group recommendations for adnexal tumors, who desired fertility preservation before definitive surgical treatment.

INTERVENTION(S)

Cryopreservation of ex vivo-retrieved mature metaphase II oocytes is followed by fertilization with donor sperm and embryo transfer to a gestational carrier.

MAIN OUTCOME MEASURE(S)

Fertility preservation.

RESULTS

After controlled ovarian stimulation, 12 metaphase II oocytes were retrieved from oophorectomized specimens and vitrified. Intracytoplasmic sperm injection with donor sperm was performed in remission, resulting in 9 cleavage-stage embryos, 2 of which were transferred to a gestational carrier, resulting in a normal, healthy singleton pregnancy, and the live birth of a healthy infant.

CONCLUSION(S)

Ex vivo oocyte retrieval after oophorectomy may be a safe alternative to standard oocyte retrieval for fertility preservation in women with ovarian malignancies.

Gonadotropin elevation is ootoxic to ovulatory oocytes and inhibits oocyte maturation, and activin decoy receptor ActRIIB:Fc therapeutically restores maturation

BACKGROUND

Elevated FSH often occurs in women of advanced maternal age (AMA, age ≥ 35) and in infertility patients undergoing controlled ovarian stimulation (COS). There is controversy on whether high endogenous FSH contributes to infertility and whether high exogenous FSH adversely impacts patient pregnancy rates.

METHODS

The senescence-accelerated mouse-prone-8 (SAMP8) model of female reproductive aging was employed to assess the separate impacts of age and high FSH activity on the percentages (%) of viable and mature ovulated oocytes recovered after gonadotropin treatment. Young and midlife mice were treated with the FSH analog equine chorionic gonadotropin (eCG) to model both endogenous FSH elevation and exogenous FSH elevation. Previously we showed the activin inhibitor ActRIIB:Fc increases oocyte quality by preventing chromosome and spindle misalignments. Therefore, ActRIIB:Fc treatment was performed in an effort to increase % oocyte viability and % oocyte maturation.

RESULTS

The high FSH activity of eCG is ootoxic to ovulatory oocytes, with greater decreases in % viable oocytes in midlife than young mice. High FSH activity of eCG potently inhibits oocyte maturation, decreasing the % of mature oocytes to similar degrees in young and midlife mice. ActRIIB:Fc treatment does not prevent eCG ootoxicity, but it restores most oocyte maturation impeded by eCG.

CONCLUSIONS

FSH ootoxicity to ovulatory oocytes and FSH maturation inhibition pose a paradox given the well-known pro-growth and pro-maturation activities of FSH in the earlier stages of oocyte growth. We propose the FOOT Hypothesis ("FSH OoToxicity Hypothesis), that FSH ootoxicity to ovulatory oocytes comprises a new driver of infertility and low pregnancy success rates in DOR women attempting spontaneous pregnancy and in COS/IUI patients, especially AMA women. We speculate that endogenous FSH elevation also contributes to reduced fecundity in these DOR and COS/IUI patients. Restoration of oocyte maturation by ActRIB:Fc suggests that activin suppresses oocyte maturation in vivo. This contrasts with prior studies showing activin A promotes oocyte maturation in vitro. Improved oocyte maturation with agents that decrease endogenous activin activity with high specificity may have therapeutic benefit for COS/IVF patients, COS/IUI patients, and DOR patients attempting spontaneous pregnancies.

Poland Syndrome in a Pregnancy From an Assisted Reproductive Technology (ART) Cycle With In Vitro Maturation (IVM) and Rescue Intracytoplasmic Sperm Injection (ICSI)

Poland syndrome is a congenital anatomical anomaly, characterised by partial or total aplasia of one side of the body causing abnormalities affecting the chest, shoulder, and upper limb. The exact mechanism that leads to this syndrome is unknown, but an abnormality in the vasculature formation or interruption of the blood supply of the subscapular artery and its branches early in development may be the main cause. Depending on the underlying mechanism, the syndrome has several expressions with some hardly being detectable and others not even being compatible with life. Here, we present a case of pregnancy from an assisted reproductive technology (ART) cycle with in vitro maturation (IVM) and rescue intra cytoplasmic sperm injection (ICSI), which resulted in the in-utero death of the foetus. The subsequent necropsy revealed a variation of Poland syndrome.

Clinical outcomes from ART in predicted hyperresponders: in vitro maturation of oocytes versus conventional ovarian stimulation for IVF/ICSI

STUDY QUESTION

Do ongoing pregnancy rates (OPRs) differ in predicted hyperresponders undergoing ART after IVM of oocytes compared with conventional ovarian stimulation (OS) for IVF/ICSI?

SUMMARY ANSWER

One cycle of IVM is non-inferior to one cycle of OS in women with serum anti-Müllerian hormone (AMH) levels ≥10 ng/ml.

WHAT IS KNOWN ALREADY

Women with high antral follicle count and elevated serum AMH levels, indicating an increased functional ovarian reserve, are prone to hyperresponse during ART treatment. To avoid iatrogenic complications of OS, IVM has been proposed as a mild-approach alternative treatment in predicted hyperresponders, including women with polycystic ovary syndrome (PCOS) who are eligible for ART. To date, inferior pregnancy rates from IVM compared to OS have hampered the uptake of IVM by ART clinics. However, it is unclear whether the efficiency gap between IVM and OS may differ depending on the extent of AMH elevation.

STUDY DESIGN, SIZE, DURATION

This study is a retrospective cohort analysis of clinical and laboratory data from the first completed highly purified hMG (HP-hMG) primed, non-hCG-triggered IVM or OS (FSH or HP-hMG stimulation in a GnRH antagonist protocol) cycle with ICSI in predicted hyperresponders ≤36 years of age at a tertiary referral university hospital. A total of 1707 cycles were included between January 2016 and June 2022.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Predicted hyperresponse was defined as a serum AMH level ≥3.25 ng/ml (Elecsys® AMH, Roche Diagnostics). The primary outcome was cumulative ongoing pregnancy rate assessed 10-11 weeks after embryo transfer (ET). The predefined non-inferiority limit was -10.0%. The analysis was adjusted for AMH strata. Time-to-pregnancy, defined as the number of ET cycles until ongoing pregnancy was achieved, was a secondary outcome. Statistical analysis was performed using a multivariable regression model controlling for potential confounders.

MAIN RESULTS AND THE ROLE OF CHANCE

Data from 463 IVM cycles were compared with those from 1244 OS cycles. Women in the IVM group more often had a diagnosis of Rotterdam PCOS (434/463, 93.7%) compared to those undergoing OS (522/1193, 43.8%), were significantly younger (29.5 years versus 30.5 years, P ≤ 0.001), had a higher BMI (25.7 kg/m2 versus 25.1 kg/m2, P ≤ 0.01) and higher AMH (11.6 ng/ml versus 5.3 ng/ml, P ≤ 0.001). Although IVM cycles yielded more cumulus-oocyte complexes (COCs) (24.5 versus 15.0 COC, P ≤ 0.001), both groups had similar numbers of mature oocytes (metaphase II (MII)) (11.9 MII versus 10.6 MII, P = 0.9). In the entire cohort, non-adjusted cumulative OPR from IVM was significantly lower (198/463, 42.8%) compared to OS (794/1244, 63.8%), P ≤ 0.001. When analysing OPR across different serum AMH strata, cumulative OPR in both groups converged with increasing serum AMH, and OPR from IVM was non-inferior compared to OS from serum AMH levels >10 ng/ml onwards (113/221, 51.1% (IVM); 29/48, 60.4% (OS)). The number of ETs needed to reach an ongoing pregnancy was comparable in both the IVM and the OS group (1.6 versus 1.5 ET's, P = 0.44). Multivariable regression analysis adjusting for ART type, age, BMI, oocyte number, and PCOS phenotype showed that the number of COCs was the only parameter associated with OPR in predicted hyperresponders with a serum AMH >10 ng/ml.

LIMITATIONS, REASONS FOR CAUTION

These data should be interpreted with caution as the retrospective nature of the study holds the possibility of unmeasured confounding factors.

WIDER IMPLICATIONS OF THE FINDINGS

Among subfertile women who are eligible for ART, IVM, and OS resulted in comparable reproductive outcomes in a subset of women with a serum AMH ≥10 ng/ml. These findings should be corroborated by a randomised controlled trial (RCT) comparing both treatments in selected patients with elevated AMH.

STUDY FUNDING/COMPETING INTEREST(S)

There was no external funding for this study. P.D. has been consultant to Merck Healthcare KGaA (Darmstadt, Germany) from April 2021 till June 2023 and is a Merck employee (Medical Director, Global Medical Affairs Fertility) with Merck Healthcare KGAaA (Darmstadt, Germany) since July 2023. He declares honoraria for lecturing from Merck KGaA, MSD, Organon, and Ferring. The remaining authors declared no conflict of interest pertaining to this study.

TRIAL REGISTRATION NUMBER

N/A.