Faculty Bibliography

The objective of this review is to provide an update on planned oocyte cryopreservation. This fertility preservation method increases reproductive autonomy by allowing women to postpone childbearing whilst maintaining the option of having a biological child. Oocyte cryopreservation is no longer considered experimental, and its use has increased dramatically in recent years as more women delay childbearing for personal, professional and financial reasons. Despite increased usage, most patients who have undergone oocyte cryopreservation have not yet warmed their oocytes. Most women who cryopreserve oocytes wait years to use them, and many never use them. Studies have demonstrated that oocyte cryopreservation results in live birth rates comparable with IVF treatment using fresh oocytes, and does not pose additional safety risks to offspring. Based on current evidence, cryopreserving ≥20 mature oocytes at <38 years of age provides a 70% chance of one live birth. However, larger studies from a variety of geographic locations and centre types are needed to confirm these findings. Additional research is also needed to determine the recommended age for oocyte cryopreservation, recommended number of oocytes to cryopreserve, return and discard/non-use rates, cost-effectiveness, and how best to distribute accurate and up-to-date information to potential patients.

OBJECTIVE:To review the outcomes of patients who underwent autologous oocyte thaw after planned oocyte cryopreservation. DESIGN/METHODS:Retrospective cohort study. SETTING/METHODS:Large urban university-affiliated fertility center. PATIENT(S)/METHODS:All patients who underwent ≥1 autologous oocyte thaw before December 31, 2020. INTERVENTION(S)/METHODS:None. MAIN OUTCOME MEASURE(S)/METHODS:The primary outcome was the final live birth rate (FLBR) per patient, and only patients who had a live birth (LB) or consumed all remaining inventory (cryopreserved oocytes and resultant euploid/untested/no result embryos) were included. The secondary outcomes were laboratory outcomes and LB rates per transfer. RESULT(S)/RESULTS:A total of 543 patients underwent 800 oocyte cryopreservations, 605 thaws, and 436 transfers. The median age at the first cryopreservation was 38.3 years. The median time between the first cryopreservation and thaw was 4.2 years. The median numbers of oocytes and metaphase II oocytes (M2s) thawed per patient were 14 and 12, respectively. Overall survival of all thawed oocytes was 79%. Of all patients, 61% underwent ≥1 transfer. Among euploid (n = 262) and nonbiopsied (n = 158) transfers, the LB rates per transfer were 55% and 31%, respectively. The FLBR per patient was 39%. Age at cryopreservation and the number of M2s thawed were predictive of LB; the FLBR per patient was >50% for patients aged <38 years at cryopreservation or who thawed ≥20 M2s. A total of 173 patients (32%) have remaining inventory. CONCLUSION(S)/CONCLUSIONS:Autologous oocyte thaw resulted in a 39% FLBR per patient, which is comparable with age-matched in vitro fertilization outcomes. Studies with larger cohorts are necessary.

OBJECTIVE:To determine how often a noneuploid result from a single trophectoderm (TE) biopsy tested with the next-generation sequencing (NGS)-based preimplantation genetic testing for aneuploidy (PGT-A) is concordant with rebiopsies tested with a single-nucleotide polymorphism (SNP) array-based PGT-A platform. DESIGN/METHODS:Blinded prospective cohort study. SETTING/METHODS:University-affiliated fertility center. PATIENT(S)/METHODS:One hundred blastocysts were chosen from donated samples; on TE biopsy with NGS-based PGT-A, 40 had at least one whole chromosome full copy number aneuploidy alone, 20 had a single whole chromosome intermediate copy number ("whole chromosome mosaic"), 20 had a single full segmental aneuploidy (segA), and 20 had a single segmental intermediate copy number ("segmental mosaic"). INTERVENTIONS/METHODS:Four rebiopsies were collected from each embryo: 3 TE biopsies and the remaining embryo. Each rebiopsy was randomized, blinded, and assessed with an SNP array-based PGT-A platform that combines copy number and allele ratio analyses, without mosaicism reporting. MAIN OUTCOME MEASURE(S)/METHODS:Concordance between the NGS result and rebiopsy results and within each embryo's blinded rebiopsy results. RESULT(S)/RESULTS:Next-generation sequencing-diagnosed whole chromosome aneuploidy (WCA) was reconfirmed in 95% (95% confidence interval [CI], 83%-99%) of embryos; 2 embryos with NGS-diagnosed WCA were called euploid on all conclusive rebiopsies. Among embryos with NGS-diagnosed whole chromosome mosaicism, 35% (95% CI, 15%-59%) were called euploid and 15% (95% CI, 3%-38%) were called whole chromosome aneuploid on all conclusive rebiopsies. A total of 30% (95% CI, 12%-54%) of embryos with NGS-diagnosed segA and 65% (95% CI, 41%-85%) of embryos with NGS-diagnosed segmental mosaicism were called euploid on all conclusive rebiopsies. In total, 13% (95% CI, 6%-25%) of embryos with NGS-diagnosed full copy number aneuploidy and 50% (95% CI, 34%-66%) of embryos with NGS-diagnosed mosaicism had uniformly euploid SNP results. Conversely, all embryos with at least one noneuploid SNP result (n = 72) either had SNP-diagnosed aneuploidy on another rebiopsy from the same embryo or NGS-diagnosed aneuploidy/mosaicism involving the same chromosome. CONCLUSION(S)/CONCLUSIONS:Next-generation sequencing-diagnosed WCA is highly concordant with rebiopsies tested with an SNP array-based PGT-A; however, whole chromosome mosaicism, segA, and segmental mosaicism are less concordant, reinforcing that embryos with these results may have reproductive potential and be suitable for transfer.

PURPOSE/OBJECTIVE:To assess the impact of sperm source on cumulative live birth rate (CLBR) after oocyte thaw in autologous oocyte cryopreservation (AOC) patients. METHODS:A retrospective cohort study of autologous oocyte thaw patients at an urban academic fertility center from 2006 to 2021. Patients were stratified by sperm source [partner sperm (PS) vs. donor sperm (DS)]. The primary outcome was CLBR per patient. Secondary outcomes were the oocyte survival rate and usable embryo rate. Statistics included Mann-Whitney U, Kruskal-Wallis, Fisher's exact, chi-square, two-sample t-tests, and multiple logistic regression (p < 0.05). RESULTS:A total of 653 patients were included; 455 (69.7%) used PS and 198 (30.3%) used DS. Time from the first AOC to the first thaw did not differ among DS and PS users (56.8 vs. 54.0 months, p = 0.20). PS users were younger at AOC (37.9 vs. 38.5 years, p < 0.001) and thaw (42.3 vs. 43.1 years, p < 0.001). There were equivalent overall CLBRs (39.9% PS vs. 40.6% DS, p = 0.85) and CLBRs in patients < 35 years at AOC (51.2% PS vs. 100% DS, p = 0.18), 35-37 years at AOC (45.9% PS vs. 60.4% DS, p = 0.10), 38-40 years at AOC (35.4% PS vs. 35.2% DS, p = 0.93), 41-42 years at AOC (28.9% PS vs 14.3% DS, p = 0.21), and > 43 years at AOC (12.5% PS vs 16.7% DS, p = 0.83) among PS and DS users. There were no significant differences in the oocyte survival (79% PS vs 80.5% DS, p = 0.08) or the proportion of patients with usable embryos (27.3% vs 27.8%, p = 0.70) between PS and DS groups. CONCLUSIONS:In AOC patients, CLBR, oocyte survival rate, and usable embryo rate did not differ based on sperm source.

PURPOSE/OBJECTIVE:To examine the effects of age, mature oocyte number, and cycle number on cumulative live birth rates after planned oocyte cryopreservation (OC), with the goal of developing a patient counselling tool. METHODS:We performed a retrospective cohort study of all patients with ≥ 1 autologous oocyte thaw at our university-affiliated fertility center before 12/31/2023. Patients were included if they (1) had a live birth or ongoing pregnancy > 12 weeks from OC, or (2) used all oocytes and euploid/untested embryos from OC. Primary outcome was cumulative live birth / ongoing pregnancy rate (CLBR). RESULTS:527 patients with 1 OC cycle, 149 patients with 2 OC cycles, and 55 patients with ≥ 3 OC cycles were included. Overall CLBR was 43%. CLBR was > 70% among patients who thawed ≥ 20 mature oocytes that were cryopreserved at age < 38 years. Multiple logistic regression showed that age at first OC and total number of mature oocytes thawed independently predicted CLBR, but number of OC cycles did not. CONCLUSION/CONCLUSIONS:Patients must be counselled that younger age at OC and more mature oocytes improve CLBR. However, additional OC cycles do not independently improve CLBR. Our results can help patients decide whether to pursue additional OC cycles to obtain more oocytes.

PURPOSE/OBJECTIVE:Our aim was to evaluate if maternal age at transfer following autologous oocyte cryopreservation is associated with live birth rate (LBR). METHODS:We performed a retrospective cohort study of all patients who thawed autologous oocytes and then underwent a single frozen euploid embryo transfer between 2011 and 2021 at a large urban university-affiliated fertility center. Each oocyte thaw patient was matched 2:1 to in vitro fertilization (IVF) patients who underwent single embryo transfer < 1 year after retrieval. Primary outcome was LBR. Secondary outcomes included implantation rates (IR) and spontaneous abortion rates (SABR). RESULTS:A total of 169 oocyte thaw patients were matched to 338 IVF patients. As expected, oocyte thaw patients were older (median age 42.5 vs. 37.6 years, p < 0.001) and waited longer between retrieval and transfer than in vitro fertilization patients (median time 59 vs. 1 month, p < 0.001). In univariate analysis, implantation and LBR differed among oocyte thaw and IVF patients (p < 0.05), but SABR did not (p = 0.57). Transfer outcomes in oocyte thaw patients did not differ based on transfer age group (IR: p = 0.18; SABR: p = 0.12; LBR: p = 0.24). In a multiple logistic regression model, age at transfer was not predictive of live birth when controlling for age at retrieval, embryo morphology, and day of blastulation. CONCLUSIONS:Maternal age at transfer after oocyte cryopreservation is not predictive of LBR; this suggests that "an aging womb" does not impair LBR after oocyte thaw and empowers patients to return for transfer when ready for childbearing.

PURPOSE/OBJECTIVE:To evaluate live birth rates (LBRs) for in vitro fertilization (IVF) cycles with ≤5 follicles at trigger, with the goal of helping patients with low follicle counts decide whether to proceed to retrieval. METHODS:This is a retrospective cohort study from an urban, university-affiliated fertility center. All IVF cycles that yielded <10 oocytes between 2016 and 2020 were reviewed. Cycles were included if <5 follicles measuring >14 mm were verified on trigger day. The primary outcome was LBR per retrieval after fresh or frozen transfer. Secondary outcomes were number of oocytes, mature oocytes, 2-pronuclear zygotes (2-PNs), blastocysts for transfer/biopsy, and euploid blastocysts (if preimplantation genetic testing for aneuploidy (PGT-A) was used). RESULTS:1502 cycles (900 with PGT-A) from 972 patients were included. Mean number of oocytes, mature oocytes, 2-PNs, blastocysts for transfer/biopsy, and euploid blastocysts differed by follicle number (p < 0.001). Across all age groups, there were differences in LBR associated with follicle number (p < 0.001). However, within age groups, not all results were significant. For example, for patients <35 years, LBR did not differ by follicle number and among patients 35-37 years; LBR with two or three follicles was lower than with five (p < 0.02). LBR for patients 35-40 years was <20% with 1-3 follicles and 25-40% with 4-5 follicles. LBR for patients >41 years was <5% with 1-3 follicles and <15% with 4-5 follicles. CONCLUSION/CONCLUSIONS:As expected, LBR is higher with more follicles. Providing patients with <5 follicles with specific data can help them weigh the emotional, physical, and financial costs of retrieval.

PURPOSE/OBJECTIVE:To evaluate pre-implantation genetic testing for aneuploidy (PGT-A) outcomes in patients without infertility compared to infertile patients. METHODS:We performed a retrospective cohort study of all patients without an infertility diagnosis ("fertile" patients) who utilized PGT-A at a large university-affiliated fertility center between 2016 and 2021. Fertile patients were 1-to-3 matched to infertile controls by age and number of oocytes retrieved. The primary outcome was blastocyst aneuploidy rate. Secondary outcomes included ovarian reserve markers, laboratory outcomes, and other PGT-A outcomes [rates of euploidy, mosaicism, and potentially transferrable (euploid + mosaic) embryos]. RESULTS:283 fertile and 849 infertile patients were included. Median age, anti-Mullerian hormone, and day 2 estradiol levels were equivalent among groups; day 2 follicle-stimulating hormone levels were higher in fertile patients (6.9 vs. 6.5 IU/mL, p < 0.01). The aneuploidy rate was similar among fertile and infertile patients (33.7% vs. 31.8%, p = 0.11); the euploidy rate was higher (50.8% vs. 47.0%, p < 0.01), and the mosaicism rate was lower in fertile patients (13.3% vs. 19.2%, p < 0.01). The rate of transferrable embryos was similar among groups (64.0% vs. 66.3%, p = 0.07), as was the percentage of patients yielding ≥ 1 euploid embryo (90.1% vs. 87.3%, p = 0.25). When controlling for significant covariates, multiple linear regression showed that aneuploidy rate was equivalent in both cohorts. CONCLUSION/CONCLUSIONS:Aneuploidy rate was similar in fertile and infertile patients. Fertile patients had slightly higher euploidy and lower mosaicism than infertile patients. Still, compared to fertile patients, infertile patients had equivalent rates of transferrable embryos and were just as likely to yield ≥ 1 euploid embryo.

Objective: Planned OC is increasing; yet, there is a lack of thaw data to provide an accurate estimate of CLBR.¹ We reviewed our AO thaws to determine CLBR by age and #AOs.
Material(s) and Method(s): We reviewed AO thaws at our academic center from 2004-2021. Inclusion criteria: 1) >=1 live birth (LB)/ongoing pregnancy (OP) >12 weeks, or 2) all AOs + embryos from OC consumed. Exclusion criteria: 1) OC for a medical reason, as research, due to lack of sperm or a natural disaster, combined with embryos or for gestational carrier use, or 2) AOs/embryos from OC transported out before a LB. Primary outcome was CLBR (LB + OP). Patients (pts) were stratified by age and #AOs or metaphase II oocytes (M2s) thawed. If pts had >=1 OC cycle, we calculated a weighted age: [SIGMA (#AOs thawed x age at OC)] / [#AOs thawed]. Statistics included multiple logistic regression (MLR), Fischer's exact test, and chi-squared test (p<0.05 significant).
Result(s): 548 pts (median age at OC 38y, range 28-45y; 151 weighted ages used) underwent 767 OC (location: 90% our center, 9% elsewhere, 2% both; method: 77% vitrification, 4% slow cooling, 19% both), 604 thaw and 465 transfer cycles. 40% (n=218) of pts had >=1 LB/OP, resulting in 221 babies + 30 OPs. See table for CLBRs. In pts of all ages and <38y, CLBR increased as #AO/M2s thawed increased from 0-10 to 11-20 to >20 (p<0.03). In pts 38-39y, CLBR was lower if 0-10 vs. 11-20 or >20 AOs were thawed (p<0.01), but was similar if 11-20 vs. >20 AOs (p=0.34) or M2s (p=0.13) were thawed. In pts >=40y, CLBR did not differ based on #AOs (p=0.81) or M2s thawed (p=0.17). For pts with any # or >20 AO/M2s thawed, CLBR was higher in pts <38y and 38-39y vs. pts >=40y (p<0.04). In a MLR model adjusting for effect of age on #AOs, age and age-independent #AOs were predictive of LB.
Conclusion(s): CLBR increases as more AO/M2s are thawed. OC at <38y has a CLBR of ~50%, a reasonable rate in younger pts at an ideal age for OC. Impact Statement: Pts who freeze >20 AOs at <38y can expect >=70% CLBR based on actual outcomes. This is the largest report to date of AO thaw outcomes from a single U.S. center. [Formula presented] REFERENCES:: 1 Practice Committee of the American Society for Reproductive Medicine. Evidence-based outcomes after oocyte cryopreservation for donor oocyte in vitro fertilization and planned oocyte cryopreservation: a guideline. Fertil Steril. 2021 Jul;116(1):36-47.
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