Ovarian tissue cryopreservation: Low usage rates and high live-birth rate after transplantation

Cryopreservation of ovarian cortex as fertility preservation in transgender men: A case report and literature review

Transgender people have been experiencing significant advancements in their social visibility, although they continue to face frequent discrimination and exclusion. Among the issues encompassing transgender individuals' health care, the right to reproductive and sexual health have gained traction in the study landscape, necessitating an exploration of fertility preservation options for these patients. This report sheds light on the process of cryopreserving gametes and ovarian tissue after total hysterectomy with bilateral salpingo-oophorectomy for gender reassignment in a transgender man in hormonal masculinization. The procedure resulted in the cryopreservation of three immature oocytes and ovarian tissue fragments. The objective of this study is to contribute to the promotion of knowledge and the sharing of experiences, aiming to gradually enhance the attention on reproductive health among transgender individuals.

Ovarian tissue cryopreservation for fertility preservation: a two-decade single-center experience with 451 children and adolescents

BACKGROUND

Ovarian tissue cryopreservation (OTC) is the only fertility preservation option for premenarcheal girls before gonadotoxic treatment, but is still considered to be experimental in pediatric patients. This study investigated storage behaviors across different age groups to refine counseling approaches for pediatric patients.

METHODS

This retrospective study analyzed data from children (0-14 years), adolescents (15-19 years), and adults (≥ 20 years) who underwent OTC between 2000-2021 at the University Hospital Bonn's cryobank. Comparison to adults (age ≥ 20 years) was conducted.

RESULTS

Of 2,475 patients, 6% were children and 12% adolescents. Sarcoma was most common in children, lymphoma in adolescents. Adults had longer active storage than children (5.5 vs. 4.7 years, p = 0.011), but for active storage ≥ 10 years, children and adolescents stored longer than adults (13.1 and 12.6 vs. 11.8 years, p ≤ 0.01). The proportion of adolescents increased, while that of children decreased in long-term storage. Median ovarian cortex surface before cryopreservation was 3.5 cm2 in children and 4.5 cm2 in adolescents. Leukemia and sarcoma had the highest mortality rates in children (25% and 13.5%). Overall, pregnancy and birth rates following ovarian tissue transplantation (OTT) were 34.5% and 24.1%, respectively. Among adolescents, pregnancy rates were 33.3% after OTT and 27.3% without OTT, while all children without OTT achieved pregnancy (100%).

CONCLUSIONS

Children and adolescents represent a small subset of OTC patients, with indications linked to common pediatric malignancies. For active storage ≥ 10 years, they store longer than adults, likely due to delayed reproduction or awaiting in vitro growth / in vitro maturation in hematological cases. Overall, adults store longer, but adolescent storage has risen over time possibly due to higher child mortality and previously limited OTC use in younger patients. Mean ovarian cortex surface data may guide pediatric tissue harvest recommendations, with unilateral oophorectomy advised. Fertility preservation counseling and cost coverage should be standard for pediatric patients undergoing gonadotoxic treatment. A tailored approach to OTC indications is essential, especially in high-mortality cancers like leukemia or sarcoma. Favorable pregnancy rates observed, even without OTT, suggest possible OTC overutilization, highlighting the need for individualized strategies and careful clinical decision-making to balance risks and preserve reproductive potential.

Single-cell analysis comparing early-stage oocytes from fresh and slow-frozen/thawed human ovarian cortex reveals minimal impact of cryopreservation on the oocyte transcriptome

STUDY QUESTION

Does the slow-freezing and thawing process have a negative impact on the transcriptome of oocytes isolated from early-stage human follicles compared to fresh controls?

SUMMARY ANSWER

The transcriptional profiles of fresh and frozen/thawed oocytes did not cluster separately, indicating undetectable differences between the two groups when compared to within-donor heterogeneity.

WHAT IS KNOWN ALREADY

Previous studies using histological analysis of follicle morphology, density, and stage distribution in slow-frozen/thawed human ovarian cortex compared to fresh controls showed no differences between the two groups. Clinical cases reported in the past 10 years have demonstrated that transplanted slow-frozen/thawed and fresh ovarian cortex restored normal serum FSH levels and regular menstrual cycles by 5 months. However, the slow-frozen and thawed tissue resulted in lower rates of pregnancies and live births, albeit not statistically significant.

STUDY DESIGN, SIZE, DURATION

We utilized single-cell RNA-sequencing (scRNAseq) of 144 human oocytes isolated from cadaver ovaries obtained from three donors.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human ovarian cortex from three healthy premenopausal donors 16, 18, and 27 years old was cut into squares measuring 10 × 10 × 1 mm3 and either slow-frozen and thawed or processed fresh. First, using a novel method for isolating live oocytes from primordial and primary follicles, the ovarian cortex squares were fragmented with a McIlwain tissue chopper and enzymatically digested. Next, oocytes were mechanically denuded under a dissection microscope and placed individually into wells containing lysis buffer for scRNAseq. Lysed single oocytes were subjected to library prep using the seqWell PlexWell rapid single-cell RNA protocol. Pooled libraries were subjected to 150-bp paired-end sequencing on the NovaSeq6000 Illumina platform. In total, we sequenced 144 oocytes-24 oocytes isolated fresh and 24 oocytes isolated after slow-freezing and thawing from each of the three donors. Additionally, we performed histological analysis of fresh and frozen/thawed ovarian cortex tissue from all three donors using hematoxylin and eosin staining and analyzed morphology, follicle density, and follicle stage distribution differences between fresh and cryopreserved ovarian cortex.

MAIN RESULTS AND THE ROLE OF CHANCE

The histological analysis revealed no differences in follicle stage distribution or follicle morphology between conditions, with the percentage of normal follicles in fresh and frozen/thawed tissue, respectively, as 86.7% and 91.0% for Donor 1, 91.7% and 92.5% for Donor 2, and 96.1% and 91.1% for Donor 3. The follicle density per mm3 in fresh and frozen/thawed tissue, respectively, was 279.4 and 235.8 for Donor 1, 662.2 and 553.5 for Donor 2, and 55.8 and 71.4 for Donor 3. The difference in follicle density was not statistically significant between fresh and frozen/thawed conditions for Donors 2 and 3, and significant (P = 0.017) for Donor 1. The stromal cell densities in fresh and frozen/thawed tissue, respectively, were 0.014 in both conditions for Donor 1, 0.014 and 0.016 for Donor 2, and 0.013 and 0.014 for Donor 3. There was no statistically significant difference in stromal cell density between conditions in Donor 1 and Donor 3, though it was statistically significant (P ≤ 0.001) for Donor 2. The transcriptional profiles of fresh and frozen/thawed oocytes did not cluster separately, suggesting insignificant differences between the two groups. However, at the group mean level, there was a small shift between the fresh and frozen/thawed oocytes and the shifts were parallel across the three donors. In this comparison, fresh oocytes were enriched for gene ontology terms related to chromosome segregation and mitosis, whereas frozen/thawed oocytes were enriched for terms related to wound response, cAMP signaling, and extracellular matrix organization.

LARGE SCALE DATA

Datasets available on Zenodo.org. DOI: https://zenodo.org/records/13224872.

LIMITATIONS, REASONS FOR CAUTION

In this study, we only sequenced the oocytes isolated from early-stage follicles due to technical challenges collecting and sequencing the somatic cells surrounding the oocytes. Investigating the transcriptomic changes after freezing and thawing in the somatic cells would need to be studied in the future. Additionally, we built RNAseq libraries immediately after thawing focusing on the immediate changes. Investigation of the effects that manifest at later timepoints, either in culture or upon implantation in an animal model, may reveal additional effects of the freeze/thaw process on the transcriptome.

WIDER IMPLICATIONS OF THE FINDINGS

The only clinically approved method of fertility preservation for prepubertal cancer patients and adult patients who cannot delay cancer treatment is ovarian tissue cryopreservation. Investigation of cryopreservation-induced changes in follicles at all stages is critical to further our understanding of the safety and efficacy of using these tissues for fertility preservation in the clinic. Our study is the first to analyze transcriptomic changes between individual fresh and slow-frozen/thawed human oocytes collected from early-stage follicles. To accomplish this, we developed a novel method for dissociating both fresh and frozen/thawed human ovarian cortex to obtain live denuded oocytes from early-stage follicles. Our findings provide insights into the use of cryopreserved tissue and follicles for fertility preservation efforts.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by National Institutes of Health (NIH) R01HD099402, Career Training in Reproductive Biology (CTRB) Training Grant National Institutes of Health (NIH) T32 to Jordan Machlin, National Institutes of Health (NIH) F31-HD106626 and National Institutes of Health (NIH) T31H-D079342 to Andrea Jones, National Institutes of Health (NIH) T32-GM70449 to D. Ford Hannum, and The Chan Zuckerberg Initiative Grant CZF2019-002428. We have no conflicts of interest to declare.

Longitudinal reproductive healthcare pathways of transmasculine people

BACKGROUND

It is recommended that transgender and gender diverse people receive fertility counselling before the start of gender affirming treatment. During this consultation their reproductive wishes and options for fertility preservation are explored. Transmasculine people have various options to fulfil their reproductive wishes also during gender-affirming treatment. Our aim is to study reproductive wishes and fertility preservation outcome in transmasculine people over time.

METHODS

Transmasculine individuals at the Centre of Expertise on Gender Dysphoria (CEGD) in Amsterdam were included in a prospective follow-up cohort study for gynaecological care and received follow-up questionnaires after 6, 12 and 24 months after fertility counselling regarding their reproductive wishes and fertility preservation. Reproductive outcomes were collected from the patient's medical files.

RESULTS

In total, 317 had a fertility consultation at the CEGD, of whom 10% underwent oocyte cryopreservation, 4% cortex preservation, 1% carried a pregnancy, and 12% underwent an ovariectomy. The most common reproductive choices are opting to preserve their internal organs and no fertility preservation wish. During a 2-year follow-up period, reproductive wishes changed in 20% of the participants. This was not related to age, testosterone use or prior puberty suppression. However, there was a trend suggesting that younger age and prior puberty suppression were related to changes in reproductive wishes.

CONCLUSION

This study showed reproductive wishes of transmasculine individuals over time. Further research is necessary to follow the reproductive outcomes of oocyte cryopreservation, cortex preservation and pregnancy. As well as, factors that influence their future pathway to parenthood.

Ex vivo removal of pro-fibrotic collagen and rescue of metabolic function in human ovarian fibrosis

Tissue fibrosis, with the excessive accumulation of extracellular matrix, leads to organ dysfunction. The ovary shows signs of fibrosis from an early age, creating a permissive environment for ovarian cancer. A robust culture-platform to study human ovarian fibrosis would enable screens for antifibrotic drugs to prevent or even reverse this process. Based on previous results showing that androgen therapy can induce ovarian fibrosis, we characterized the fibrotic state of ovaries from transmasculine donors of reproductive age. Anti-inflammatory and antioxidant drugs, such as Pirfenidone, Metformin, and Mitoquinone, could reduce and revert the excess collagen content of the ovarian cortical tissue during culture. We demonstrated that Metformin exerts an antioxidant role and prevents a glycolytic metabolic shift in non-immune ovarian stromal cells in the human ovary, while promoting early folliculogenesis during culture. These results may contribute to develop strategies to manage pro-tumorigenic fibrotic ovarian stroma in advanced age and metabolic disorders.

Local delivery of platelet-derived factors mitigates ischemia and preserves ovarian function through angiogenic modulation: A personalized regenerative strategy for fertility preservation

As the most prominent and ideal modality in female fertility preservation, ovarian tissue cryopreservation, and transplantation often confront the challenge of ischemic damage and follicular loss from avascular transplantation. To surmount this impediment, we engineered a novel platelet-derived factors-encapsulated fibrin hydrogel (PFH), a paradigmatic biomaterial. PFH encapsulates autologous platelet-derived factors, utilizing the physiological blood coagulation cascade for precise local delivery of bioactive molecules. In our study, PFH markedly bolstered the success of avascular ovarian tissue transplantation. Notably, the quantity and quality of follicles were preserved with improved neovascularization, accompanied by decreased DNA damage, increased ovulation, and superior embryonic development rates under a Low-concentration Platelet-rich plasma-derived factors encapsulated fibrin hydrogel (L-PFH) regimen. At a stabilized point of tissue engraftment, gene expression analysis mirrored normal ovarian tissue profiles, underscoring the effectiveness of L-PFH in mitigating the initial ischemic insult. This autologous blood-derived biomaterial, inspired by nature, capitalizes on the blood coagulation cascade, and combines biodegradability, biocompatibility, safety, and cost-effectiveness. The adjustable properties of this biomaterial, even in injectable form, extend its potential applications into the broader realm of personalized regenerative medicine. PFH emerges as a promising strategy to counter ischemic damage in tissue transplantation, signifying a broader therapeutic prospect. (197 words).

Perinatal outcomes of pregnancies following autologous cryopreserved ovarian tissue transplantation: a systematic review with pooled analysis

OBJECTIVE

This study aimed to synthesize the existing evidence on perinatal outcomes after autologous cryopreserved ovarian tissue transplantation, concurrently identifying key factors influencing these outcomes.

DATA SOURCES

A comprehensive search was performed on MEDLINE, Embase, and Cochrane Library databases to identify relevant studies on the effect of autologous cryopreserved ovarian tissue transplantation on perinatal outcomes from inception to October 22, 2023. Where there was missing information, the authors were contacted for updated data.

STUDY ELIGIBILITY CRITERIA

Observational studies, such as cohort studies, case series, and case reports that reported a live birth after autologous cryopreserved ovarian tissue transplantation, were considered eligible. Studies lacking data on women's demographic characteristics, autologous cryopreserved ovarian tissue transplantation procedure details, or perinatal outcomes were excluded. In addition, cases involving fresh or nonautologous transplantations and those addressing primary ovarian insufficiency were excluded.

METHODS

Two reviewers (M.E. and E.U.) independently performed the study selection, data extraction, and risk of bias assessment, and the results were then reviewed together. The PRISMA guidelines were followed, and the protocol was registered on PROSPERO (CRD42023469296).

RESULTS

This review included 58 studies composed of 122 women with 162 deliveries (154 singletons and 8 twins) after autologous cryopreserved ovarian tissue transplantation, resulting in 170 newborns. Of note, 83.6% of the women had a malignant disease. Moreover, most of these women (51.0%) were exposed to some form of chemotherapy before ovarian tissue cryopreservation. Of the 162 childbirths, 108 (66.7%) were conceived naturally, and 54 (33.3%) were conceived through assisted reproductive techniques. The birthweight of 88.5% of newborns was appropriate for gestational age, whereas 8.3% and 3.1% were small for gestational age and large for gestational age, respectively. The preterm birth rate was 9.4%, with the remaining being term deliveries. Hypertensive disorders of pregnancy were noted in 18.9% of women, including pregnancy-induced hypertension in 7.6%, preeclampsia in 9.4%, and hemolysis, elevated liver enzymes, and low platelet count in 1.9%. The incidences of gestational diabetes mellitus and preterm premature rupture of membranes were 3.8% for each condition. Neonatal anomalies were reported in 3 transplant recipients with 4 newborns: arthrogryposis, congenital cataract, and diaphragmatic hernia in a twin. Finally, among the recipients' characteristics, not receiving chemotherapy before ovarian tissue cryopreservation (odds ratio, 0.23; 95% confidence interval, 0.07-0.72; P=.012) and natural conception (odds ratio, 0.29; 95% confidence interval, 0.09-0.92; P=.035) were associated with a lower perinatal complication rate.

CONCLUSION

On the basis of low certainty evidence from observational studies, perinatal complication rates did not increase after autologous cryopreserved ovarian tissue transplantation compared with the general pregnant population, except for preeclampsia. This could be due to chemotherapy exposure, underlying medical conditions, and the common use of assisted reproductive techniques. Further larger studies are needed to explore the causes of increased preeclampsia incidence in autologous cryopreserved ovarian tissue transplantation pregnancies.

Novel Advances in Cell-Free Therapy for Premature Ovarian Failure (POF): A Comprehensive Review

Premature ovarian failure (POF), is a condition characterized by the early decline of ovulation function. POF is a complex disorder that can be caused by various factors, and the idiopathic form represents a significant proportion of POF patients. Hormone replacement therapy (HRT) is currently considered the first-line treatment for POF. This review aims to provide a comprehensive overview of recent advancements in platelet-rich plasma (PRP), in vitro activation (IVA), stem cell therapy, exosome therapy, microRNAs, and mitochondrial targeting therapies as a promising cell-free therapeutic approach in reproductive medicine. PLT-Exos, a new generation of cells, has been used to treat POF for more than a decade and has been shown to attenuate oocyte morphology and promote the differentiation of theca cells through the upregulation of PI3K/Akt and Bcl2, as well as the downregulation of the Smad and Bax signaling pathways. This review summarizes the current state of the art in the field of PLT-Exos and discusses the advantages and limitations of their potential clinical applications.

Assessing Attitudes and Understanding After Ovarian Tissue Cryopreservation: A Follow-Up Telephone Interview Survey

Purpose: Assessing patient and guardian experiences regarding their history of ovarian tissue cryopreservation (OTC) years after initial procedure. Methods: Cross-sectional follow-up telephone survey. A questionnaire developed by The Pediatric Initiative Network of the Oncofertility Consortium, modified to assess intent and attitudes regarding OTC, tissue access knowledge, financial burden of tissue storage, and intent to use tissue, was utilized. Interviews were conducted for those who underwent OTC at a metropolitan children's hospital between 2013 and 2022. Results: Of 60 eligible patients, 39 interviews were completed. Contacted patients were 3-28 years old, with minors accompanied by guardians. Average age at OTC was 8.5 years old, and 5.1% (2/39) were deceased at the time of contact. All interviewees underwent OTC for fertility preservation before gonadotoxic treatment. Seventy percent of patients (7/10) and 48.1% (13/27) of guardians stated they would use frozen tissue for pregnancy, with 50% (5/10) of patients and 59.3% (16/27) of guardians not understanding tissue access. Regret occurred in 10% (1/10) of patients and 3.4% (1/29) of guardians. It was associated with 10.8% (4/37) of tissue discard due to failed storage payments. Financial concerns occurred in 29.7% (11/37) of interviewees. Overall, 92.3% (36/39) would recommend OTC, and 94.9% (37/39) would repeat their choice to undergo OTC. Conclusion: Follow-up after OTC is essential to patient understanding of tissue status, access, and payments. Most do not regret OTC, except in cases of financial burden leading to tissue discard. Follow-up should be sequentially scheduled and include counseling on financial assistance programs.

Fertility preservation in women with endometriosis: Oocyte cryopreservation and other techniques

In recent years, advancements in cryopreservation techniques for oocytes, embryos, and ovarian tissue have enabled offering fertility preservation (FP) options to women with endometriosis. It is recommended to always conduct specialized counselling on FP, especially before considering surgical interventions for endometriosis. The decision regarding the methods of FP, the timing, and to which women affected by endometriosis these techniques should be offered are still subjects of discussion. However, several studies suggest that it can be proposed before surgical interventions for endometriosis, particularly if the patient is undergoing mono or bilateral endometrioma surgery. The most recommended technique is ovarian stimulation, followed by oocyte cryopreservation. Nevertheless, the literature contains various studies describing FP through embryo cryopreservation or the retrieval and cryopreservation of ovarian tissue.

Ovarian tissue transplantation: 10 years of experience at the Bologna University

Objective

The efficiency of ovarian tissue transplantation (OTT) was established in terms of ovarian function recovery (95% of cases), number of live births (over 200 worldwide to date) and induction of puberty. Unfortunately, the lack of international registries and the fact that many centers have not yet reported their outcomes, lead to poor knowledge of the exact fertility data. The aim of the study is to describe our experience with OTT to restore ovarian function and fertility.

Methods

This study was designed as a single-center, observational, retrospective, cohort study that includes women who underwent OTT between December 2012 and June 2023 at our center. After approval by the oncologist/hematologist, a small fragment of ovarian tissue was thawed and analyzed to detect the presence of micrometastases before OTT. Thawed ovarian tissue was grafted laparoscopically at multiple sites, including the remaining ovary and pelvic side wall (orthotopic transplantation) and/or abdominal wall (heterotopic transplantation). After OTT, ovarian function was monitored by hormonal assay, ultrasound and color Doppler at approximately 4-week intervals.

Results

Between December 2012 and June 2023, 30 women performed OTT. Prior to OTT, immunohistochemical and molecular analyses revealed no micrometastases in all thawed ovarian tissue samples. In our series of 30 women, 20 of women were on premature ovarian insufficiency (POI), and the remaining ten cases still had oligomenorrhea and difficulty getting pregnant. Among the women with POI before OTT and at least 6 months follow-up, recovery of endocrine function was observed in all but one woman who underwent orthotopic transplantation (13 of 14 cases), in one out of two women who underwent both orthotopic and heterotopic transplantation (1 of 2 cases) and in all women who underwent heterotopic transplantation (4 of 4 cases). Women who underwent OTT to enhance fertility had no alterations in menstrual cycle and hormonal levels. In total, ten pregnancies were obtained in 25 women, resulting in four live births, two ongoing pregnancies and four spontaneous abortions.

Conclusion

Our data can help patients and physicians in their discussions and decisions about the need and possibilities of preserving fertility.

Reconstruction of ovarian follicular-like structure by recellularization of a cell-free human ovarian scaffold with mouse fetal ovarian cells

The present study assessed the supportive roles of the decellularized human ovarian tissue in homing of mouse fetal ovarian cells into the scaffold as well as the formation of the follicular-like structure. The human ovarian cortical tissues were decellularized by three freeze-thaw cycles and then, treated with Triton X-100 for 15 h and 0.5% sodium dodecyl sulfate for 72 h. After isolation and preparation of mouse fetal ovarian cells (19 dpc) they were seeded into the decellularized scaffolds and cultured for 7 days, then using a light microscope, laser confocal scanning microscope, and scanning electron microscope these scaffolds were studied. Analysis of gene expression related to oocyte and follicular cells such as Ddx4, Nobox, Gdf9, and Connexin37 was assessed by real-time RT-PCR and the DDX4 and GDF9 proteins were detected by immunohistochemistry. The result showed that the human ovarian tissue was decellularized properly and the tissue elements and integrity were well preserved. After 7 days of in vitro culture, the fetal ovarian cells attached and penetrated into different sites and depths of the scaffold. The formed organoid within the scaffold showed large round, small polyhedral, and elongated spindle cells similar to the follicle structure. The molecular analysis and immunohistochemistry were confirmed an increase in the expression of genes and proteins related to oocyte and follicular cells in these reconstructed structures. In conclusion, the recellularization of human ovarian scaffolds by mouse fetal ovarian cells could support the follicular-like structure formation and it provides an in vitro model for follicle reconstitution and offers an alternative approach for clinical usage.

Successful pregnancy rates amongst patients undergoing ovarian tissue cryopreservation for non-malignant indications: A systematic review and meta-analysis

BACKGROUND

Ovarian tissue cryopreservation (OTC) is a fertility preservation method that has been clinically applied for almost 30 years. Studies specifically evaluating patients presenting with non-malignant indications for OTC and their subsequent pregnancy rates are limited.

OBJECTIVE

To summarise the evidence on the rates of successful pregnancy amongst women who have undergone OTC for non-malignant indications.

METHODS

A systematic review with meta-analysis (PROSPERO registration CRD42022307925) was conducted to investigate the pregnancy outcomes of patients who have undergone ovarian tissue cryopreservation for non-malignant indications. Articles published in EMBASE and Ovid MEDLINE before October 2022 were screened for inclusion based on the following criteria: original human studies pertaining to OTC with a defined non-malignant cohort and pregnancy outcomes. The successful pregnancy rates were pooled with a random-effects model of double-arcsine transformed proportions. Sensitivity analysis involved pooling the results of studies with a low risk of bias after being assessed with NIH tools.

RESULTS

The database search retrieved 3,225 results, of which 16 were included in the meta-analysis. The pooled successful pregnancy rate was 23.52 % (16 studies, 95 % CI 6.48 to 44.79 %). When subgroup analysis of study types was performed, the successful pregnancy rate was higher amongst case series (47.02 %, 9 studies, 95 % CI 6.98 to 89.00 %) than cohort studies (14.64 %, 7 studies, 95 % CI 3.59 to 29.78 %). Sensitivity analysis limited to studies at low risk of bias revealed a similar pooled successful pregnancy rate of 23.35 % (12 studies, 95 % CI 2.50 to 51.96 %).

CONCLUSIONS

Approximately one quarter of women who underwent OTC for non-malignant indications had a successful pregnancy. These findings are clinically important for fertility preservation counselling by providing greater evidence for more informed care.

Assessing the impact of transplant site on ovarian tissue transplantation: a single-arm meta-analysis

BACKGROUND

Survival rates of young women undergoing cancer treatment have substantially improved, with a focus on post-treatment quality of life. Ovarian tissue transplantation (OTT) is a viable option to preserve fertility; however, there is no consensus on the optimal transplantation site. Most studies on OTT are nonrandomized controlled trials with limited sample sizes and uncontrolled statistical analyses, leaving the question of which transplant site yields the highest chance of achieving a live birth unanswered.

OBJECTIVE

This meta-analysis aimed to assess the effect of different ovarian transplant sites on postoperative reproductive outcomes.

METHODS

We adhered to the PRISMA Reporting Items for Systematic Reviews and Meta-Analyses recommendations. Systematic searches were conducted in PubMed, Embase, Web of Science, and the Cochrane Library from inception to September 17, 2023. The inclusion criteria were as follows: (1) women who underwent OTT with a desire for future childbirth, and (2) reports of specific transplant sites and corresponding pregnancy outcomes. The exclusion criteria included the inability to isolate or extract relevant outcome data, case reports, non-original or duplicate data, and articles not written in English.

RESULTS

Twelve studies (201 women) were included in the meta-analysis of cumulative live birth rates (CLBR) after OTT. The CLBR, which encompasses both spontaneous pregnancies and those achieved through assisted reproductive technology (ART) following OTT to the ovarian site, was 21% (95% CI: 6-40, I2: 52.81%, random effect). For transplantation to the pelvic site, the live birth rate was 30% (95% CI: 20-40, I2: 0.00%, fixed effect). Combining transplantation to both the pelvic and ovarian sites resulted in a live birth rate of 23% (95% CI: 11-36, I2: 0.00%, fixed effect). Notably, heterotopic OTT yielded a live birth rate of 3% (95% CI: 0-17, I2: 0.00%, fixed effect).

CONCLUSION

Pregnancy outcomes were not significantly different after orthotopic ovarian transplantation, and pregnancy and live birth rates after orthotopic OTT were significantly higher than those after ectopic transplantation.

REGISTRATION NUMBER

INPLASY202390008.

Effects of different subcutaneous sites on heterotopic autotransplantation of canine ovarian tissue

Ovarian tissue transplantation makes it possible to restore fertility; however, the success of this technique depends on the transplant region used. Therefore, this study aimed to evaluate the effect of two subcutaneous regions on canine ovarian transplantation, pinna (Pi) and neck (Ne), for 7 and 15 days. Ovaries collected by ovariosalpingohysterectomy were fragmented using a punch device. Fresh fragments were fixed, and the others were immediately grafted onto the animal itself in the Pi and Ne regions for 7 and 15 days. Recovered fragments were evaluated for histology (morphology, development and stromal density), picrosirius (collagen fibers), and immunohistochemistry (fibrosis and cell proliferation). The results showed that follicular normality rates were lower in Pi-7 (78%) vs. control (90%) and Pi-15 (86%), similar in Ne-7 (92%) and superior in Ne-15 (97%) compared to the control, with the effect of the region Ne (94%) superior (P < 0.05) to Pi (82%). Stromal density reduced in both regions vs. control but was similar within 15 days. Fragments from both regions showed higher fibronectin labeling and deposition of type I and lower type III collagen fibers (P < 0.05) vs. control. Proliferation rates in Ne-7 were higher (P < 0.05) than in control, and Pi-15 was higher (P < 0.05) than Ne-15. In conclusion, the pinna may be a region with greater potential than the neck after a 15-day autotransplantation of canine ovarian tissue.

Leuprolide Protects Ovarian Reserve in Adolescents Undergoing Gonadotoxic Therapy

Purpose: Treatment sequelae compromising reproductive health are highly prevalent in childhood cancer survivors, and a main determinant of health and quality of life. Follicular reserve determines ovarian function life span; thus, its preservation is important in the care of female survivors. Anti-Müllerian hormone (AMH) is a biomarker to measure functional ovarian reserve. We aimed to evaluate the effect of leuprolide during gonadotoxic therapy on pubertal females' post-treatment functional ovarian reserve using AMH levels. Methods: We conducted a single-center retrospective study including all pubertal females who had undergone gonadotoxic treatments between January 2010 and April 2020, and had an AMH level after completion of therapy. We used multivariable linear regressions to compare AMH-level beta coefficients in patients stratified by gonadotoxic risk, adjusting for leuprolide use. Results: Fifty-two females meeting study eligibility were included, of which 35 received leuprolide. The use of leuprolide was associated with higher post-treatment AMH levels in the lower gonadotoxic risk group (beta 2.74, 95% CI 0.97-4.51; p = 0.004). This association was lost in the higher gonadotoxic risk groups. Conclusions: Leuprolide may have a protective effect on the functional ovarian reserve. However, this is limited by increasing treatment gonadotoxicity. Larger, prospective studies are needed to elucidate the potential benefits of gonadotropin-releasing hormone agonist on preservation of ovarian reserve among children receiving gonadotoxic therapies, as cancer survivors.

Optimizing the Ovarian Tissue Cryopreservation in the 'Oncofertility' Institutional Program at an Italian National Cancer Institute

BACKGROUND

The majority of female cancer patients undergoing anticancer treatments are at risk of experiencing 'cancer treatment-related infertility', which can result in permanent damage to their reproductive prospects. Among the fertility preservation methods, ovarian tissue cryopreservation (OTC) has emerged as an alternative for these patients. The Cancer Institute of Bari initiated a research program to assess the feasibility of OTC. This study compares the viability of ovarian cortical fragments cryopreserved using slow freezing (SF) and ultra-rapid freezing (URF) methods.

METHODS

Ovarian cortex biopsies were obtained from 11 fertile women enrolled in our oncofertility service between June 2022 and January 2023. After tissue collection, a histological assessment was performed before cryopreservation. OTC was carried out using both SF and URF methods. Six months later, thawed samples were evaluated for follicle counts and histological integrity.

RESULTS

No statistically significant difference was observed in the proportion of intact follicles (means of 31.5% and 73.0% in the SF and URF groups, respectively; p = 0.064). However, there was a significant difference in the number of follicles between the SF group (n = 149) and the URF group (n = 37) (p = 0.046).

CONCLUSIONS

We assessed the viability of ovarian cortex after freezing and thawing, focusing on the structural integrity of follicles. Our findings suggest that there are no significant differences between the SF and URF methods.

A 16-year bicentric retrospective analysis of ovarian tissue cryopreservation in pediatric units: indications, results, and outcome

Background

Cancer treatments of the last decades improve the survival rate of children and adolescents. However, chemo- and radiotherapy result in gonadal damage, leading to acute ovarian failure and sterility. The preservation of fertility is now an integral part of care of children requiring gonadotoxic treatments. Ovarian tissue cryopreservation (OTC) is an effective fertility preservation option that allows long-term storage of primordial follicles, subsequent transplantation, and restoration of endocrine function and fertility. The efficacy of this technique is well-demonstrated in adults but the data are scarce for pediatric patients. Currently, OTC represents the only possibility of preserving the potential fertility in prepubertal girls.

Procedure

This is a retrospective study of OTC practice of two French centers from January 2004 to May 2020. A total of 72 patients from pediatric units underwent cryopreservation of ovarian tissue before gonadotoxic therapy for malignant or non-malignant diseases. The ovarian cortex was cut into fragments and the number of follicles per square millimeter was evaluated histologically. The long-term follow-up includes survival rate and hormonal and fertility status.

Results

The mean age of patients at OTC was 9.3 years [0.2-17] and 29.2% were postpubertal; 51 had malignant diseases and 21 had non-malignant diseases. The most frequent diagnoses included acute leukemia, hemoglobinopathies, and neuroblastoma. Indication for OTC was stem cell transplantation for 81.9% (n = 59) of the patients. A third of each ovary was collected for 62.5% (n = 45) of the patients, a whole ovary for 33.3% (n = 24) of the patients, and a third of one ovary for 4.2% (n = 3) of the patients. An average of 17 fragments [5-35] per patient was cryoconserved. A correlation was found between the age of the patients and the number of fragments (p < 0.001). More fragments were obtained from partial bilateral harvesting than from whole ovary harvesting (p < 0.05). Histological analysis of ovarian tissue showed a median of 6.0 primordial follicles/mm2 [0.0-106.5] and no malignant cells were identified. A negative correlation was found between age and follicular density (p < 0.001). Median post-harvest follow-up was 92 months [1-188]. A total of 15 girls had died, 11 were still under treatment for their pathology, and 46 were in complete remission. Of all patients, 29 (40.2%) were subjected to a hormonal status evaluation and 26 were diagnosed with premature ovarian insufficiency (POI) (p < 0.001). One patient had undergone thawed ovarian tissue transplantation.

Conclusion

OTC should be proposed to all girls with high risk of developing POI following gonadotoxic therapies in order to give them the possibility of fertility and endocrine restoration.

Perfusion and Ultrasonication Produce a Decellularized Porcine Whole-Ovary Scaffold with a Preserved Microarchitecture

The application of decellularized scaffolds for artificial tissue reconstruction has been an approach with great therapeutic potential in regenerative medicine. Recently, biomimetic ovarian tissue reconstruction was proposed to reestablish ovarian endocrine functions. Despite many decellularization methods proposed, there is no established protocol for whole ovaries by detergent perfusion that is able to preserve tissue macro and microstructure with higher efficiency. This generated biomaterial may have the potential to be applied for other purposes beyond reproduction and be translated to other areas in the tissue engineering field. Therefore, this study aimed to establish and standardize a protocol for porcine ovaries' decellularization based on detergent perfusion and ultrasonication to obtain functional whole-ovary scaffolds. For that, porcine ovaries (n = 5) were perfused with detergents (0.5% SDS and 1% Triton X-100) and submitted to an ultrasonication bath to produce acellular scaffolds. The decellularization efficiency was evaluated by DAPI staining and total genomic DNA quantification. ECM morphological evaluation was performed by histological, immunohistochemistry, and ultrastructural analyses. ECM physico-chemical composition was evaluated using FTIR and Raman spectroscopy. A cytocompatibility and cell adhesion assay using murine fibroblasts was performed. Results showed that the proposed method was able to remove cellular components efficiently. There was no significant ECM component loss in relation to native tissue, and the scaffolds were cytocompatible and allowed cell attachment. In conclusion, the proposed decellularization protocol produced whole-ovaries scaffolds with preserved ECM composition and great potential for application in tissue engineering.

Fertility preservation, its effectiveness and its impact on disease status in pre-menopausal women with breast cancer: A systematic review and meta-analysis

INTRODUCTION

Preservation of reproductive function is a key concern for many premenopausal women with breast cancer, given the known gonadotoxic effects of treatments. The present systematic review aimed to investigate the effectiveness and safety of fertility preservation strategies in pre-menopausal women with breast cancer.

METHODS

Primary research assessing fertility preservation strategies of any type was identified. Markers of preservation of fertility including return of menstrual function, clinical pregnancy rates and live birth rates were selected as main outcome measures. An additional analysis of safety data was also performed.

RESULTS

Fertility preservation interventions were overall associated with higher fertility outcomes: with a pooled odds ratio 4.14 (95% CI 3.59-4.77) for any kind of fertility preservation intervention. This was seen both for return of menstruation and for clinical pregnancy rate, but not for live birth rates. Fertility preservation was associated with a reduced rate of disease recurrence (OR 0.63 (95% CI 0.49-0.81)), while there was no significant difference in disease free survival (OR 0.88 (95% CI 0.74-1.05)) or in overall survival (OR 0.9 (95% CI 0.74-1.10)) between the fertility preservation group and those who had not undergone fertility preservation.

CONCLUSION

Fertility preservation is both effective in preserving reproductive function, and safe with regard to disease recurrence, disease free survival and overall survival in premenopausal women with breast cancer.

Current Trends on Bioengineering Approaches for Ovarian Microenvironment Reconstruction

Ovarian tissue has a unique microarchitecture and a complex cellular and molecular dynamics that are essential for follicular survival and development. Due to this great complexity, several factors may lead to ovarian insufficiency, and therefore to systemic metabolic disorders and female infertility. Techniques currently used in the reproductive clinic such as oocyte cryopreservation or even ovarian tissue transplant, although effective, have several limitations, which impair their wide application. In this scenario, mimetic ovarian tissue reconstruction comes as an innovative alternative to develop new methodologies for germ cells preservation and ovarian functions restoration. The ovarian extracellular matrix (ECM) is crucial for oocyte viability maintenance, once it acts actively in folliculogenesis. One of the key components of ovarian bioengineering is biomaterials application that mimics ECM and provides conditions for cell anchorage, proliferation, and differentiation. Therefore, this review aims at describing ovarian tissue engineering approaches and listing the main limitations of current methods for preservation and reestablishment of ovarian fertility. In addition, we describe the main elements that structure this study field, highlighting the main advances and the challenges to overcome to develop innovative methodologies to be applied in reproductive medicine. Impact Statement This review presents the main advances in the application of tissue bioengineering in the ovarian tissue reconstruction to develop innovative solutions for ovarian fertility reestablishment.

The effect of platelet lysate on mouse ovarian structure, function and epigenetic modifications after autotransplantation

RESEARCH QUESTION

What are the effects of platelet lysate on structure, function and epigenetic modifications of heterotopically transplanted mouse ovarian tissues?

DESIGN

Mice were divided into three groups (n = 17 per group): control (mice with no ovariectomy, grafting or treatment), autograft and autograft plus platelet lysate (3 ml/kg at the graft sites). Inflammatory markers, serum malondialdehyde (MDA) concentration and total antioxidant capacity were assessed on day 7 after transplantation. Twenty-eight days after transplantation, stereological and hormonal analyses were conducted. Chromatin immunoprecipitation and quantitative real-time polymerase chain reaction were also used to quantify the epigenetic modifications of maturation genes, parallel to their expression.

RESULTS

The total volume of the ovary, cortex and medulla, and the number of different types of follicles, the concentration of interleukin (IL)-10, progesterone and oestradiol and total antioxidant capacity significantly decreased in the autograft group compared with the control group (P < 0.001); these parameters significantly increased in the autograft plus platelet lysate group compared with the autograft group (P < 0.001). The concentrations of tumour necrosis factor alpha, IL-6 and MDA increased significantly in the autograft group compared with the control group (P < 0.001); in the autograft plus platelet lysate group, these parameters significantly decreased compared with the autograft group (P < 0.001). In the autograft plus platelet lysate group, the expression levels of Gdf-9 (P < 0.0021), Igf-1 (P < 0.0048) and Igf-2 (P < 0.0063) genes also increased along with a lower incorporation of MeCP2 in the promoter regions (P < 0.001) compared with the autograft group.

CONCLUSIONS

Platelet lysate can contribute to follicular survival by improving folliculogenesis and increasing the expression of oocyte maturation genes.

The effect of high-throughput vitrification of human ovarian cortex tissue on follicular viability: a promising alternative to conventional slow freezing?

BACKGROUND

The standard procedure most frequently used for ovarian tissue cryopreservation (OTC) is slow freezing, while vitrification has been proposed as promising alternative and has built an impressive catalog of success in fertility laboratories regarding cryopreservation of oocytes and embryos.

METHODS

We developed and evaluated a high-throughput protocol for vitrification of human ovarian tissue suitable for clinical processing. Follicular viability was assessed via calcein staining prior and after cryopreservation analyzing ovarian tissue of a cohort of 30 patients.

RESULTS

We found no significant differences regarding follicular viability between slow frozen and vitrified cortex tissue samples 24 h after thawing and rapid warming. Follicular viability of thawed and rapid warmed samples was not significantly different in comparison to fresh samples, indicating high proportions of follicular survival rates with both methods.

CONCLUSIONS

High-throughput vitrification is a promising option in a clinical setting. More research is required to determine the status of other tissue-specific quality indicators potentially influencing on autotransplantation.

Ovarian tissue cryopreservation and transplantation: 20 years experience in Bologna University

Objective

To report the 20-year experience in ovarian tissue cryopreservation (OTC) and ovarian tissue transplantation (OTT) of the Bologna clinical center (Bologna, Italy).

Design

Retrospective cohort study.

Patients

1026 pediatrics and women aged between 2 and 38 years who underwent OTC and OTT between January 2002 to January 2022.

Results

Of the 1026 patients, 238 (22.8%) were pediatrics (≤ 17 years, Group 1) and 788 (77.2%) were adult women (range 18-38 years, Group 2). In Group 1, 184 (77.3%) patients had malignant diseases and 54 (22.7%) had non-malignant diseases. In Group 2, 746 (94.7%) patients had malignant diseases and 42 (5.3%) had non-malignant diseases. No real complications were observed during surgery. In all the samples analyzed most of the follicles were in the resting stage, while only a few follicles were growing. In both fresh and thawed samples, follicular density was higher in Group 1 than in Group 2 (p < 0.01). Regardless of age, good preservation of follicles and stroma was observed in fresh and thawed ovarian tissue by histological and immunohistochemical analyses (estrogen and progesterone receptors; Ki67 and Bcl2 markers; TUNEL). To date, out of 1026 total women, 812 (79.1%) had their tissue stored. Sixty-eight (6.6%) patients died from their primary disease. Twenty-four (2.3%) women performed 33 OTTs between December 2011 and January 2022. Restoration of menstruation was observed in 15 out of 17 menopausal women. Six pregnancies were achieved, two hesitated in abortion and four in the birth of healthy babies.

Conclusion

OTC is the only fertility preservation technique applicable in pre-pubertal/pediatrics and in adult patients when stimulation for oocytes/embryos cryopreservation is not possible. The reported data can help future patients and physicians in their discussions and decisions about the need and possibilities of preserving ovarian function.

The effect of hematopoietic stem cell transplantation on fertility and strategies for improvement

Ovarian dysfunction is an important consequence of hematopoietic stem cell transplantation (HCT). Premature ovarian failure and infertility can severely impact the quality of life for the increasing number of female long-term survivors of HCT. Here, we review the impact of HCT on ovarian function, post-transplant fertility and birth outcomes, and the contemporaneous strategies to preserve fertility for these patients.

Ovarian Tissue Cryopreservation in Children and Adolescents

Cancer during childhood and adolescence remains a major public health issue, affecting a significant portion of this age group. Although newer anti-cancer treatments have improved survival rates, this comes at a cost in terms of gonadotoxic effects. As a result, the preservation of fertility is important. Ovarian tissue cryopreservation, one of the newest methods, has some advantages, especially for prepubertal patients: no need for ovarian stimulation, thus, no further risk for estrogen-sensitive cancer types, and preservation of more and better-quality primordial follicles of the ovarian cortex. The most frequent indications include treatment with alkylating agents, ovarian-focused radiotherapy, leukemias, lymphomas, brain and neurological tumors, as well as Turner syndrome and benign hemoglobinopathies. An expected survival exceeding 5 years, the absence of systematic disease and an overall risk of premature ovarian insufficiency over 50% are among the criteria that need to be fulfilled in order for a patient to undertake this method. Orthotopic transplantation is more frequently used, since it can allow both live birth and the recovery of endocrine function. Reimplantation of malignant cells is always a major risk and should always be taken into consideration. Histological analysis, as well as immunohistochemical and molecular methods, are needed in order to improve the search for malignant cells before transplantation. Ovarian tissue cryopreservation appears to be a method with specific benefits, indications and risks which can be an important tool in terms of preserving fertility in younger women.

Ovarian tissue cryopreservation and transplantation for fertility preservation

Background: As the number of cancer survivors has increased with advancements in cancer treatment, fertility preservation has become a treatment goal. Ovarian tissue cryopreservation (OTC) and transplantation (OTT) has made great progress over the past few decades. It has become the treatment of choice for fertility preservation in adolescents or patients in urgent need of chemotherapy. However, it is considered to be experimental compared with oocyte or embryo cryopreservation in some countries. Nevertheless, OTC and OTT is regarded as the more ideal method for fertility preservation in that it can also restore hormonal functions.Current Concepts: Currently, over 200 live births have been reported worldwide after OTC and OTT, proving the excellence of the technology. However, before its application in clinical settings, some challenges, including cryoinjury, ischemic injury, and cancer cell reimplantation, should be overcome. For cryoinjury, studies are underway on protocol improvement with the addition of agents such as antifreeze protein during cryopreservation. For ischemic injury, various agents have been studied to promote angiogenesis or revascularization. Furthermore, studies are underway on artificial ovary or xenotransplantation for fertility preservation in an effort to avoid cancer cell metastasis.Discussion and Conclusion: OTC and OTT is a clinically applicable option for fertility preservation. To set OTC and OTT as an established method for fertility preservation, further research is necessary to overcome the current challenges.

L-Carnitine improves follicular survival and function in ovarian grafts in the mouse

CONTEXT

Ovarian tissue transplantation is performed to preserve fertility in patients undergoing chemotherapy and radiotherapy. However, the ischemia-reperfusion injury which occurs after the ovarian tissue transplantation causes follicular depletion and apoptosis. l -Carnitine has antioxidant and anti-inflammation properties.

AIMS

Therefore, we aimed to investigate the beneficial effect of l -carnitine on mouse ovaries following heterotopic autotransplantation.

METHODS

Mice were randomly divided into three groups (six mice per group): control, autografted and autografted+l -carnitine (200mg/kg daily intraperitoneal injections). Seven days after ovary autografting, the serum levels of malondialdehyde (MDA), total antioxidant capacity, tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and IL-10 were measured. Ovary histology, serum concentrations of progesterone and estradiol were also measured 28days after autotransplantation. Data were analysed using one-way analysis of variance (ANOVA) and Tukey test, and the means were considered significantly different at P Key results: In the autografted+l -carnitine group, the total volume of the ovary, the volume of the cortex, the number of follicles, the serum concentrations of IL-10, estradiol and progesterone significantly increased compared to the autografted group. In the autografted+l -carnitine group, serum concentrations of IL-6, TNF-α and MDA were significantly decreased compared to the autografted group.

CONCLUSIONS

Our results indicated that l -carnitine can ameliorate the consequences of ischemia-reperfusion on the mice ovarian tissue following autotransplantation.

IMPLICATIONS

l -carnitine improves the structure and function of transplanted ovaries.

Exogenous Melatonin Ameliorates the Negative Effect of Osmotic Stress in Human and Bovine Ovarian Stromal Cells

Ovarian tissue cryopreservation transplantation (OTCT) is the most flexible option to preserve fertility in women and children with cancer. However, OTCT is associated with follicle loss and an accompanying short lifespan of the grafts. Cryopreservation-induced damage could be due to cryoprotective agent (CPA) toxicity and osmotic shock. Therefore, one way to avoid this damage is to maintain the cell volume within osmotic tolerance limits (OTLs). Here, we aimed to determine, for the first time, the OTLs of ovarian stromal cells (OSCs) and their relationship with reactive oxygen species (ROS) and mitochondrial respiratory chain activity (MRCA) of OSCs. We evaluated the effect of an optimal dose of melatonin on OTLs, viability, MRCA, ROS and total antioxidant capacity (TAC) of both human and bovine OSCs in plated and suspended cells. The OTLs of OSCs were between 200 and 375 mOsm/kg in bovine and between 150 and 500 mOsm/kg in human. Melatonin expands OTLs of OSCs. Furthermore, melatonin significantly reduced ROS and improved TAC, MRCA and viability. Due to the narrow osmotic window of OSCs, it is important to optimize the current protocols of OTCT to maintain enough alive stromal cells, which are necessary for follicle development and graft longevity. The addition of melatonin is a promising strategy for improved cryopreservation media.

Fresh and cryopreserved ovarian tissue transplantation for preserving reproductive and endocrine function: a systematic review and individual patient data meta-analysis

BACKGROUND

Ovarian tissue cryopreservation involves freezing and storing of surgically retrieved ovarian tissue in liquid or vapour nitrogen below -190°C. The tissue can be thawed and transplanted back with the aim of restoring fertility or ovarian endocrine function. The techniques for human ovarian tissue freezing and transplantation have evolved over the last 20 years, particularly in the context of fertility preservation in pre-pubertal cancer patients. Fresh ovarian tissue transplantation, using an autograft or donor tissue, is a more recent development; it has the potential to preserve fertility and hormonal function in women who have their ovaries removed for benign gynaecological conditions. The techniques of ovarian tissue cryopreservation and transplantation have progressed rapidly since inception; however, the evidence on the success of this intervention is largely based on case reports and case series.

OBJECTIVE AND RATIONALE

The aim of this study was to systematically review the current evidence by incorporating study-level and individual patient-level meta-analyses of women who received ovarian transplants, including frozen-thawed transplant, fresh or donor graft.

SEARCH METHODS

The review protocol was registered with PROSPERO (CRD42018115233). A comprehensive literature search was performed using MEDLINE, EMBASE, CINAHL and Cochrane Central Register of Controlled Trials from database inception to October 2020. Authors were also contacted for individual patient data if relevant outcomes were not reported in the published manuscripts. Meta-analysis was performed using inverse-variance weighting to calculate summary estimates using a fixed-effects model.

OUTCOMES

The review included 87 studies (735 women). Twenty studies reported on ≥5 cases of ovarian transplants and were included in the meta-analysis (568 women). Fertility outcomes included pregnancy, live birth and miscarriage rates, and endocrine outcomes included oestrogen, FSH and LH levels. The pooled rates were 37% (95% CI: 32-43%) for pregnancy, 28% (95% CI: 24-34%) for live birth and 37% (95% CI: 30-46%) for miscarriage following frozen ovarian tissue transplantation. Pooled mean for pre-transplant oestrogen was 101.6 pmol/l (95% CI: 47.9-155.3), which increased post-transplant to 522.4 pmol/l (95% CI: 315.4-729; mean difference: 228.24; 95% CI: 180.5-276). Pooled mean of pre-transplant FSH was 66.4 IU/l (95% CI: 52.8-84), which decreased post-transplant to 14.1 IU/l (95% CI: 10.9-17.3; mean difference 61.8; 95% CI: 57-66.6). The median time to return of FSH to a value <25 IU/l was 19 weeks (interquartile range: 15-26 weeks; range: 0.4-208 weeks). The median duration of graft function was 2.5 years (interquartile range: 1.4-3.4 years; range: 0.7-5 years). The analysis demonstrated that ovarian tissue cryopreservation and transplantation could restore reproductive and hormonal functions in women. Further studies with larger samples of well-characterized populations are required to define the optimal retrieval, cryopreservation and transplantation processes.

WIDER IMPLICATIONS

Ovarian tissue cryopreservation and transplantation may not only be effective in restoring fertility but also the return of reproductive endocrine function. Although this technology was developed as a fertility preservation option, it may have the scope to be considered for endocrine function preservation.

A comparison of fertility preservation outcomes in patients who froze oocytes, embryos, or ovarian tissue for medically indicated circumstances: a systematic review and meta-analysis

OBJECTIVE

To compare obstetric outcomes in patients cryopreserving reproductive cells or tissues before gonadotoxic therapy.

DESIGN

A literature search was conducted following PRISMA guidelines on Embase, Medline, and Web of Science. Studies reporting obstetric outcomes in cancer patients who completed cryopreservation of oocyte, embryo, or ovarian tissue were included.

SETTING

Not applicable.

PATIENT(S)

Cancer patients attempting pregnancy using cryopreserved cells or tissues frozen before cancer therapy.

INTERVENTION(S)

Oocyte, embryo, or ovarian tissue cryopreservation for fertility preservation in cancer.

MAIN OUTCOME MEASURE(S)

The total numbers of clinical pregnancies, live births, and miscarriages in women attempting pregnancy using cryopreserved reproductive cells or tissues were calculated. A meta-analysis determined the effect size of each intervention.

RESULT(S)

The search returned 4,038 unique entries. Thirty-eight eligible studies were analyzed. The clinical pregnancy rates were 34.9%, 49.0%, and 43.8% for oocyte, embryo, and ovarian tissue cryopreservation, respectively. No significant differences were found among groups. The live birth rates were 25.8%, 35.3%, and 32.3% for oocyte, embryo, and ovarian tissue cryopreservation, respectively, with no significant differences among groups. The miscarriage rates were 9.2%, 16.9%, and 7.5% for oocyte, embryo, and ovarian tissue cryopreservation, respectively. Significantly fewer miscarriages occurred with ovarian tissue cryopreservation than with embryo cryopreservation.

CONCLUSION(S)

This enquiry is required to counsel cancer patients wishing to preserve fertility. Although the limitations of this study include heterogeneity, lack of quality studies, and low utilization rates, it serves as a starting point for comparison of reproductive and obstetric outcomes in patients returning for family-planning after gonadotoxic therapy.

A practical survey of fertility-preservation treatments in the startup phase in Japan

AIM

The actual status of fertility preservation treatments in the startup phase in Japan was investigated as a basis for discussing future directions.

METHODS

This study was conducted as "Research project to promote support of children and parenting 2016" which was supported by Ministry of Health in Japan with the approval of the institutional review board at St. Marianna University. Subjects of the survey were facilities registered with the Japan Society of Obstetrics and Gynecology as fertility preservation facilities, and facilities belonging to the Japan Association of Private Assisted Reproductive Technology Clinics and Laboratories. We provided questionnaires to survey both the medical care system and cases for which fertility preservation was implemented between 2006 and 2016.

RESULTS

Responses were obtained from 68 facilities (of the 64, 59 [92.2%] responded to the questionnaire and 9 clinics cooperated). Many facilities limited the cryopreservation of oocytes and ovaries to patients 40-41 years old and the use of eggs to patients 44-45 years old. In the patient survey, 812 cases of oocyte cryopreservation and 201 cases of ovarian tissue cryopreservation were performed during study period. Breast cancer was the most indicated disease, with oocyte cryopreservation in the late 30s and ovarian tissue cryopreservation in the early 30s. Very few babies were born from fertility preservation, and no live birth cases of ovarian tissue cryopreservation were identified.

CONCLUSIONS

Even from the early days, fertility preservation was implemented according to certain standards in Japan, but was characterized by a large variety of facilities.

Minimal residual disease detection by multicolor flow cytometry in cryopreserved ovarian tissue from leukemia patients

Background

Cryopreservation of ovarian tissue is a fertility-preservation option for women before gonadotoxic treatments. However, cryopreserved ovarian tissue transplantation must be performed with caution in women with malignancies that may metastasize to the ovaries. For this purpose, detecting minimal residual disease (MRD) in the ovarian cortex using sensitive methods is a crucial step. We developed an automated ovarian tissue dissociation method to obtain ovarian cell suspensions.

Results

We assessed MRD by multicolor flow cytometry (MFC) in cryopreserved ovarian cortex of 15 leukemia patients: 6 with B-cell acute lymphoblastic leukemia (B-ALL), 2 with T-cell acute lymphoblastic leukemia (T-ALL) and 7 with acute myeloid leukemia (AML). Ovarian MRD was positive in 5 of the 15 leukemia patients (one T-ALL and 4 AML). No B-ALL patient was positive by MFC. Quantitative reverse-transcribed polymerase chain reaction was performed when a molecular marker was available, and confirmed the MFC results for 3 patients tested. Xenografts into immunodeficient mice were also performed with ovarian cortical tissue from 10 leukemia patients, with no evidence of leukemic cells after the 6-month grafting period.

Conclusions

In conclusion, this is the first study using MFC to detect MRD in ovarian cortical tissue from acute leukemia patients. MFC has been accepted in clinical practice for its ease of use, the large number of parameters available simultaneously, and high throughput analysis. We demonstrate here that MFC is a reliable method to detect MRD in cryopreserved ovarian tissue, with a view to controlling the oncological risk before ovarian tissue transplantation in leukemia patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-021-00936-4.

A Systematic Review of Ovarian Tissue Transplantation Outcomes by Ovarian Tissue Processing Size for Cryopreservation

Ovarian tissue cryopreservation (OTC) is the only pre-treatment option currently available to preserve fertility for prepubescent girls and patients who cannot undergo ovarian stimulation. Currently, there is no standardized method of processing ovarian tissue for cryopreservation, despite evidence that fragmentation of ovaries may trigger primordial follicle activation. Because fragmentation may influence ovarian transplant function, the purpose of this systematic review was (1) to identify the processing sizes and dimensions of ovarian tissue within sites around the world, and (2) to examine the reported outcomes of ovarian tissue transplantation including, reported duration of hormone restoration, pregnancy, and live birth. A total of 2,252 abstracts were screened against the inclusion criteria. In this systematic review, 103 studies were included for analysis of tissue processing size and 21 studies were included for analysis of ovarian transplantation outcomes. Only studies where ovarian tissue was cryopreserved (via slow freezing or vitrification) and transplanted orthotopically were included in the review. The size of cryopreserved ovarian tissue was categorized based on dimensions into strips, squares, and fragments. Of the 103 studies, 58 fertility preservation sites were identified that processed ovarian tissue into strips (62%), squares (25.8%), or fragments (31%). Ovarian tissue transplantation was performed in 92 participants that had ovarian tissue cryopreserved into strips (n = 51), squares (n = 37), and fragments (n = 4). All participants had ovarian tissue cryopreserved by slow freezing. The pregnancy rate was 81.3%, 45.5%, 66.7% in the strips, squares, fragment groups, respectively. The live birth rate was 56.3%, 18.2%, 66.7% in the strips, squares, fragment groups, respectively. The mean time from ovarian tissue transplantation to ovarian hormone restoration was 3.88 months, 3.56 months, and 3 months in the strips, squares, and fragments groups, respectively. There was no significant difference between the time of ovarian function' restoration and the size of ovarian tissue. Transplantation of ovarian tissue, regardless of its processing dimensions, restores ovarian hormone activity in the participants that were reported in the literature. More detailed information about the tissue processing size and outcomes post-transplant are required to identify a preferred or more successful processing method.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk], identifier [CRD42020189120].

Ovarian transplantation with robotic surgery and a neovascularizing human extracellular matrix scaffold: a case series in comparison to meta-analytic data

OBJECTIVE

To report our experience with robot-assisted (RA) autologous cryopreserved ovarian tissue transplantation (ACOTT) with the use of a neovascularizing extracellular matrix scaffold.

DESIGN

Case series with meta-analytic update.

SETTING

Academic.

PATIENT(S)

Seven recipients of RA-ACOTT.

INTERVENTION(S)

Before or shortly after initiating chemotherapy, ovarian tissue was cryopreserved from 7 women, who then underwent RA-ACOTT 9.9 ± 1.8 years (range, 7-12 years) later. Perioperatively, they received transdermal estrogen and low-dose aspirin to enhance graft vascularization. Ovarian cortical pieces were thawed and sutured on an extracellular matrix scaffold, which was then robotically anastomosed to the bivalved remaining ovary in 6 cases and retroperitoneally (heterotopic) to the lower abdomen in 1 case.

MAIN OUTCOME MEASURE(S)

Ovarian function return, the number of oocytes/embryos, aneuploidy %, live births, and neonatal outcomes were recorded. Graft longevity was compared with the mean from the meta-analytic data.

RESULT(S)

Ovarian function returned 13.9 ± 2.7 weeks (11-16.2 weeks) after ACOTT, and oocytes were retrieved in all cases with 12.3 ± 6.9 embryos generated. In contrast to orthotopic, the heterotopic ACOTT demonstrated low embryo quality and an 80% aneuploidy rate. A recipient did not attempt to conceive and 2 needed a surrogate, whereas 4 of 4 delivered 6 healthy children, compared with 115 of 460 (25% pregnancy rate) from the meta-analytic data (n = 79). The mean graft longevity (43.2 ± 23.6/47.4 ± 22.8 months with/without sensitivity analysis) trended longer than the meta-analytic mean (29.4 ± 22.7), even after matching age at cryopreservation.

CONCLUSION(S)

In this series, RA-ACOTT resulted in extended graft longevity, with ovarian functions restored in all cases, even when the tissues were cryopreserved after chemotherapy exposure.

Dynamic in vitro culture of cryopreserved-thawed human ovarian cortical tissue using a microfluidics platform does not improve early folliculogenesis

Current strategies for fertility preservation include the cryopreservation of embryos, mature oocytes or ovarian cortical tissue for autologous transplantation. However, not all patients that could benefit from fertility preservation can use the currently available technology. In this regard, obtaining functional mature oocytes from ovarian cortical tissue in vitro would represent a major breakthrough in fertility preservation as well as in human medically assisted reproduction. In this study, we have used a microfluidics platform to culture cryopreserved-thawed human cortical tissue for a period of 8 days and evaluated the effect of two different flow rates in follicular activation and growth. The results showed that this dynamic system supported follicular development up to the secondary stage within 8 days, albeit with low efficiency. Surprisingly, the stromal cells in the ovarian cortical tissue were highly sensitive to flow and showed high levels of apoptosis when cultured under high flow rate. Moreover, after 8 days in culture, the stromal compartment showed increase levels of collagen deposition, in particular in static culture. Although microfluidics dynamic platforms have great potential to simulate tissue-level physiology, this system still needs optimization to meet the requirements for an efficient in vitro early follicular growth.

Review of ovarian tissue cryopreservation techniques for fertility preservation

Ovarian failure and ovarian malfunction are among major fertility problems in women of reproductive age (18-35 years). It is known that various diseases, such as ovarian cancer and premature ovarian failure, besides certain treatments, such as radiotherapy and chemotherapy of other organs, can affect the normal process of folliculogenesis and cause infertility. In recent years, various procedures have been proposed for the treatment of infertility. One of the newest methods is the use of cryopreservation ovarian fragments after cancer treatment. According to some studies, this method yields very satisfactory results. Although ovarian tissue cryopreservation (OTC) is an accepted technique of fertility preservation, the relative efficacy of cryopreservation protocols remains controversial. Considering the controversies about these methods and their results, in this study, we aimed to compare different techniques of ovarian cryopreservation and investigate their advantages and disadvantages. Reviewing the published articles may be possible to identify appropriate strategies and improve infertility treatment in these patients.

Reproductive issues in carriers of germline pathogenic variants in the BRCA1/2 genes: an expert meeting

BACKGROUND

Healthy individuals and patients with cancer who are carriers of germline pathogenic variants in the BRCA1/2 genes face multiple reproductive challenges that require appropriate counseling and specific expertise.

MAIN BODY

On December 5th-7th, 2019, patient advocates and physicians with expertise in the field of reproductive medicine, fertility preservation, and oncology were invited to "San Giuseppe Moscati" Hospital in Avellino (Italy) for a workshop on reproductive management of women with germline pathogenic variants in the BRCA1/2 genes. From the discussion regarding the current evidence and future prospective in the field, eight main research questions were formulated and eight recommendations were developed regarding fertility, fertility preservation, preimplantation genetic testing, and pregnancy in healthy carriers and patients with cancer.

CONCLUSION

Several misconceptions about the topic persist among health care providers and patients often resulting in a discontinuous and suboptimal management. With the aim to offer patient-tailored counseling about reproductive issues, both awareness of current evidences and research should be promoted.

Oocyte cryopreservation versus ovarian tissue cryopreservation for adult female oncofertility patients: a cost-effectiveness study

PURPOSE

In December 2019, the American Society for Reproductive Medicine designated ovarian tissue cryopreservation (OTC) as no longer experimental and an alternative to oocyte cryopreservation (OC) for women receiving gonadotoxic therapy. Anticipating increased use of OTC, we compare the cost-effectiveness of OC versus OTC for fertility preservation in oncofertility patients.

METHODS

A cost-effectiveness model to compare OC versus OTC was built from a payer perspective. Costs and probabilities were derived from the literature. The primary outcome for effectiveness was the percentage of patients who achieved live birth. Strategies were compared using incremental cost-effectiveness ratios (ICER). All inputs were varied widely in sensitivity analyses.

RESULTS

In the base case, the estimated cost for OC was $16,588 and for OTC $10,032, with 1.56% achieving live birth after OC, and 1.0% after OTC. OC was more costly but more effective than OTC, with an ICER of $1,163,954 per live birth. In sensitivity analyses, OC was less expensive than OTC if utilization was greater than 63%, cost of OC prior to chemotherapy was less than $8100, cost of laparoscopy was greater than $13,700, or standardized discounted costs were used.

CONCLUSIONS

With current published prices and utilization, OC is more costly but more effective than OTC. OC becomes cost-saving with increased utilization, when cost of OC prior to chemotherapy is markedly low, cost of laparoscopy is high, or standardized discounted oncofertility pricing is assumed. We identify the critical thresholds of OC and OTC that should be met to deliver more cost-effective care for oncofertility patients.

Social Freezing: Pressing Pause on Fertility

Increasing numbers of women are undergoing oocyte or tissue cryopreservation for medical or social reasons to increase their chances of having genetic children. Social egg freezing (SEF) allows women to preserve their fertility in anticipation of age-related fertility decline and ineffective fertility treatments at older ages. The purpose of this study was to summarize recent findings focusing on the challenges of elective egg freezing. We performed a systematic literature review on social egg freezing published during the last ten years. From the systematically screened literature, we identified and analyzed five main topics of interest during the last decade: (a) different fertility preservation techniques, (b) safety of freezing, (c) usage rate of frozen oocytes, (d) ethical considerations, and (e) cost-effectiveness of SEF. Fertility can be preserved for non-medical reasons through oocyte, embryos, or ovarian tissue cryopreservation, with oocyte vitrification being a new and optimal approach. Elective oocyte cryopreservation is better accepted, supports social gender equality, and enhances women's reproductive autonomy. Despite controversies, planned oocyte cryopreservation appears as a chosen strategy against age-related infertility and may allow women to feel that they are more socially, psychologically, and financially stable before motherhood.

Ovarian tissue cryopreservation and transplantation in patients with central nervous system tumours

STUDY QUESTION

Is there a possibility of reseeding cancer cells potentially present in frozen ovarian tissue from patients with central nervous system (CNS) tumours?

SUMMARY ANSWER

Malignancy reseeding in cryopreserved ovarian tissue from 20 patients with CNS tumours was not detected by histology, immunohistochemistry (IHC), molecular biology or xenotransplantation.

WHAT IS KNOWN ALREADY

Ovarian metastasis potential has been documented in patients with leukaemia, borderline ovarian tumours, advanced breast cancer and Ewing sarcoma. However, data on the safety of transplanting frozen-thawed ovarian tissue from cancer patients with CNS tumours are still lacking.

STUDY DESIGN, SIZE, DURATION

This prospective experimental study was conducted in an academic gynaecology research laboratory using cryopreserved ovarian cortex from 20 patients suffering from CNS tumours. Long-term (5 months) xenografting was performed in immunodeficient mice.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Subjects enrolled in the study were suffering from one of six types of CNS tumours including medulloblastoma, ependymoma, primitive neuroectodermal tumours, astrocytoma, glioblastoma and germinoma. The presence of malignant cells was investigated with disease-specific markers for each patient in cryopreserved and xenografted ovarian tissue by histology, IHC via expression of neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP), and reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) for quantification of GFAP and ENO2 gene amplification.

MAIN RESULTS AND THE ROLE OF CHANCE

Serial sections of cryopreserved and xenografted ovarian tissue from 20 patients showed no malignant cells by histology. All samples were negative for NSE and GFAP, although these neural markers were expressed extensively in the patients' primary tumours. Analysis by RT-ddPCR revealed no cancer cells detected in cryopreserved and xenografted ovarian fragments from subjects with astrocytoma, ependymoma, glioblastoma or medulloblastoma. Taken together, the study found no evidence of malignancy seeding in frozen-thawed and xenotransplanted ovarian tissue from patients affected by CNS cancers.

LIMITATIONS, REASONS FOR CAUTION

This analysis cannot guarantee complete elimination of disseminated disease from all cryopreserved ovarian cortex, since we are unable to examine the fragments used for transplantation.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to be conducted in patients with CNS cancers undergoing ovarian tissue cryopreservation and transplantation, and clearly demonstrates no tumour seeding in their frozen-thawed and xenografted tissue. This information is vital for doctors to provide patients with meaningful and accurate advice on the possibilities and risks of ovarian tissue reimplantation.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique-the Excellence of Science (FNRS-EOS), number 30443682 awarded to M.-M.D. and T.Y.T.N., FNRS grant number 5/4/150/5 and FNRS-PDR Convention grant number T.0077.14 awarded to M.-M.D., grant 2018-042 from the Foundation Against Cancer awarded to A.C., and private donations (Ferrero, de Spoelberch). The authors declare no competing financial interests.

TRIAL REGISTRATION NUMBER

N/A.

Methods of Ovarian Tissue Cryopreservation: Is Vitrification Superior to Slow Freezing?-Ovarian Tissue Freezing Methods

After cancer treatment, female survivors often develop ovarian insufficiency or failure. Oocyte and embryo freezing are well-established fertility preservation options, but cannot be applied in pre-pubescent girls, in women with hormone-sensitive malignancies, or when gonadotoxic treatment cannot be delayed. Although ovarian tissue cryopreservation (OTC) has been used to restore fertility and endocrine function, the relative efficacy of its two major protocols, slow freezing and vitrification, remains controversial. This literature review evaluates clinical and lab-based studies published between January 2012 and June 2020 to determine whether vitrification, the optimal technique for oocyte and embryo cryopreservation, preserves ovarian tissue more effectively than slow freezing. Due to limited clinical data involving ovarian tissue vitrification, most clinical studies focus on slow freezing. Only 9 biochemical studies that directly compare the effects of slow freezing and vitrification of human ovarian tissue were noted. Most studies report no significant difference in follicular morphology and distribution between cryopreservation methods, but these findings must be interpreted in the context of high methodological variability. Discrepant findings regarding the effects of cryopreservation method on follicle viability, gene expression, and hormone production require further evaluation. Early clinical outcomes appear favorable for vitrification, but additional studies and longer term follow-up are needed to establish its efficacy. Sharing data through national or international registries would expedite this analysis. However, even if research corroborates conclusions of no clinical or biochemical difference between cryopreservation methods, the decreased costs and increased efficiency associated with vitrification make this method more accessible and cost-effective.

Ovarian tissue freezing and activation after thawing: an update

Background

With the growth of women’s age, ovarian failure can be caused by various factors. For the women who need chemotherapy because of cancer factors, the preservation of fertility is more urgent. The treatment of cancer is also a process in which all tissues and organs of the body are severely damaged, especially in the reproductive system.

Main body

As a new fertility preservation technology, autologous ovarian tissue cryopreservation and transplantation is developing rapidly and showing great potentiality in preserving ovarian endocrine function of young cervical cancer patients. Vitrification and slow freezing are two common techniques applied for ovarian tissue cryopreservation. Thus, cryopreserved/thawed ovarian tissue and transplantation act as an important method to preserve ovarian function during radiotherapy and chemotherapy, and ovarian cryopreservation by vitrification is a very effective and extensively used method to cryopreserve ovaries. The morphology of oocytes and granulosa cells and the structure of organelles were observed under the microscope of histology; the hormone content in the stratified culture medium of granulosa cells with the diameter of follicle was used to evaluate the development potential of ovarian tissue, and finally the ovarian tissue stimulation was determined by the technique of ovarian tissue transplantation.

Conclusions

Although there are some limitations, the team members still carry out this review to provide some references and suggestions for clinical decision-making and further clinical research.

Preservation of fertility in teenagers and young adults treated for haematological malignancies

As survival rates in teenagers and young adults diagnosed with haematological malignancies now exceed 70%, it is important that long-term quality of life, including measures to protect future fertility, are considered and discussed with patients and their families. Although discussion on the effect of planned cancer treatment on fertility is standard of care, knowledge of potential fertility treatment options and when they should be offered in haematological malignancies is not always so clear. In each case, the advice on the appropriate preservation of fertility depends upon a complex interplay of factors, weighing out the risk of future infertility against the risk of fertility preservation treatment, and recommendations must be made on a case-by-case basis. The aim of this Review is to evaluate the gonadotoxicity of treatments of prevalent haematological malignancies in teenagers and young adults, and provide an evidence-based framework to help with fertility discussion and management at the time of diagnosis, relapse or resistant disease, and in long-term follow-up settings.

Recent advances in understanding primary ovarian insufficiency

Primary ovarian insufficiency (POI) is an uncommon yet devastating occurrence that results from a premature depletion of the ovarian pool of primordial follicles. Our understanding of both putative and plausible mechanisms underlying POI, previously considered to be largely "idiopathic", has been furthered over the past several years, largely due to advances in the field of genetics and through expansion of translational models for experimental research. In this review, our goal is to familiarize the multidisciplinary readers of the F1000 platform with the strides made in the field of reproductive medicine that hold both preventative and therapeutic implications for those women who are at risk for or who have POI.

Spatial Analysis of Growing Follicles in the Human Ovary to Inform Tissue Engineering Strategies

Cancer survivorship has increased considerably, but common cancer treatments may threaten female reproductive health and fertility. In females, standard fertility preservation techniques include egg and embryo banking and ovarian tissue cryopreservation, but these methods are not suitable for all individuals. Emerging fertility preservation technologies include in vitro follicle growth and ovarian bioprosthetics. Although these platforms hold tremendous promise, they remain in the preclinical phase likely because of our inability to adequately phenocopy the complexity of the in vivo ovarian environment. The goal of this study was to use an established research archive of fixed human ovarian tissue established through the Oncofertility Consortium to better understand the dynamics and milieu of growing follicles within the human ovary. We performed a histological analysis of the immediate surroundings of primary and secondary stage follicles. We evaluated oocyte and follicle diameters of these growing follicles, analyzed their growth trajectories, and mapped their precise relationships to other stage follicles within a defined area. We also stratified our findings according to participant age and previous treatment history. Our results serve as in vivo benchmarks for follicles grown in vitro and provide insight into how follicles should be seeded spatially within bioprosthetic ovaries, potentially improving the efficacy and clinical translation of these emerging technologies. Impact statement Life-preserving cancer treatments have greatly increased survivorship. However, treatments often have off-target health consequences that threaten female reproductive health and fertility. Although several standard fertility preservation options exist, there is a constant need to explore and expand options for all populations. In vitro follicle growth and ovarian bioprosthetics are new experimental procedures, which are currently limited to proof of concept. In this study, we analyzed human ovarian tissue from a deidentified biospecimen repository to characterize the growing follicle landscape with the ultimate goal of informing bioengineering practices. This spatial analysis pinpoints the geometry of growing follicles within the human ovary and provides a framework for paralleling this environment in ex vivo platforms.