Cryopreservation of Ovarian Tissue: Opportunities Beyond Fertility Preservation and a Positive View Into the Future

Gonadotropin Activity during Early Folliculogenesis and Implications for Polycystic Ovarian Syndrome and Premature Ovarian Insufficiency: A Narrative Review

Female fertility depends on the ovarian reserve of follicles, which is determined at birth. Primordial follicle development and oocyte maturation are regulated by multiple factors and pathways and classified into gonadotropin-independent and gonadotropin-dependent phases, according to the response to gonadotropins. Folliculogenesis has always been considered to be gonadotropin-dependent only from the antral stage, but evidence from the literature highlights the role of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) during early folliculogenesis with a potential role in the progression of the pool of primordial follicles. Hormonal and molecular pathway alterations during the very earliest stages of folliculogenesis may be the root cause of anovulation in polycystic ovary syndrome (PCOS) and in PCOS-like phenotypes related to antiepileptic treatment. Excessive induction of primordial follicle activation can also lead to premature ovarian insufficiency (POI), a condition characterized by menopause in women before 40 years of age. Future treatments aiming to suppress initial recruitment or prevent the growth of resting follicles could help in prolonging female fertility, especially in women with PCOS or POI. This review will briefly introduce the impact of gonadotropins on early folliculogenesis. We will discuss the influence of LH on ovarian reserve and its potential role in PCOS and POI infertility.

New Approach to the Cryopreservation of GV Oocytes and Cumulus Cells through the Lens of Preserving the Intercellular Gap Junctions Based on the Bovine Model

Differences in structural and functional properties between oocytes and cumulus cells (CCs) may cause low vitrification efficiency for cumulus-oocyte complexes (COCs). We have suggested that the disconnection of CCs and oocytes in order to further cryopreservation in various ways will positively affect the viability after thawing, while further co-culture in vitro will contribute to the restoration of lost intercellular gap junctions. This study aimed to determine the optimal method of cryopreservation of the suspension of CCs to mature GV oocytes in vitro and to determine the level of mRNA expression of the genes (GJA1, GJA4; BCL2, BAX) and gene-specific epigenetic marks (DNMT3A) after cryopreservation and in vitro maturation (IVM) in various culture systems. We have shown that the slow freezing of CCs in microstraws preserved the largest number of viable cells with intact DNA compared with the methods of vitrification and slow freezing in microdroplets. Cryopreservation caused the upregulation of the genes Cx37 and Cx43 in the oocytes to restore gap junctions between cells. In conclusion, the presence of CCs in the co-culture system during IVM of oocytes played an important role in the regulation of the expression of the intercellular proteins Cx37 and Cx43, apoptotic changes, and oocyte methylation. Slow freezing in microstraws was considered to be an optimal method for cryopreservation of CCs.

Ethical, legal, social, and policy issues of ovarian tissue cryopreservation in prepubertal girls: a critical interpretive review

PURPOSE

Despite the increasing number of childhood cancer survivors, significant advances in ovarian tissue cryopreservation (OTC) technique and medical societies' recommendations, fertility preservation (FP) and FP discussions are not always offered as a standard of care in the pediatric context. The aim of this literature review is to understand what ethical, legal, social, and policy issues may influence the provision of FP by OTC in prepubertal girls with cancer.

METHODS

A critical interpretive review of peer-reviewed papers published between 2000 and January 2023 was conducted, guided by the McDougall's version of the critical interpretive synthesis (Dixon-Woods), to capture recurring concepts, principles, and arguments regarding FP by OTC for prepubertal girls.

RESULTS

Of 931 potentially relevant papers, 162 were included in our analysis. Data were grouped into seven thematic categories: (1) risks of the procedure, (2) unique decision-making issues in pediatric oncofertility, (3) counseling, (4) cultural and cost issues, and (5) disposition of cryopreserved reproductive tissue.

CONCLUSION

This first literature review focusing on ethical, legal, social, and policy issues surrounding OTC in prepubertal girls highlights concerns in the oncofertility debate. Although OTC is no longer experimental as of December 2019, these issues could limit its availability and the child's future reproductive autonomy. This review concludes that specific actions must be provided to enable the offer of FP, such as supporting families' decision-making in this unique and complex context, and providing pediatric patients universal and full access to free or highly subsidized OTC.

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.

Thiol-yne click crosslink hyaluronic acid/chitosan hydrogel for three-dimensional in vitro follicle development

There is a great deal of potential for in vitro follicle growth to provide an alternative approach to fertility preservation. This strategy reduces the possibility of cancer cells re-exposure after transplantation, and it does not require hormone stimulation. Adopting a three-dimensional (3D) culture method helps preserve the architecture of the follicle and promotes the maturity of oocytes. In order to maintain follicle morphology, enhance the quality of mature oocytes, and facilitate meiotic spindle assembly, the current work aimed to develop the 3D in vitro preantral mouse follicle culture method. Thiolated chitosan-co-thiolated hyaluronic (CSHS) hydrogel was designed to evaluate the effects of biomaterials on ovarian follicle development. Isolated follicles from mouse ovaries were randomly divided into alginate (Alg) as a 3D control, thiolated hyaluronic acid (HASH), and CSHS groups. Single follicle was encapsulated in each hydrogel, and performed for 10 days and subsequently ovulated to retrieve mature oocytes on day 11. CSHS hydrogel promoted follicle survival and oocyte viability with maintained spherical morphology of follicle. Matured oocytes with normal appearance of meiotic spindle and chromosome alignment were higher in the CSHS group compared with those in the Alg and HASH groups. Furthermore, CSHS increased expression level of folliculogenesis genes (TGFβ-1, GDF-9) and endocrine-related genes (LHCGR, and FSHR). With various experimental setups and clinical applications, this platform could be applied as an alternative method to in vitro follicle culture with different experimental designs and clinical applications in the long-term period.

Breast Cancer and Fertility Preservation in Young Female Patients: A Systematic Review of the Literature

INTRODUCTION

Breast cancer affects almost 1.5 million women worldwide below the age of 45 years each year. Many of these women will be advised to undergo adjuvant chemotherapy to minimize the risk of death or recurrence of the tumor. For these patients, chemotherapy is a known cause of infertility, as it can damage primordial follicles, which can lead to early menopause or premature ovarian insufficiency. This systematic review aims to synthesize the current evidence of the most suitable treatments for fertility preservation.

METHODOLOGY

This review was performed following the PRISMA guidelines. The authors conducted an extensive search from the last 15 years. Relevant studies were pursued in PubMed, Embase, and the Cochrane Library up until 31 July 2023. A total of seven eligible studies were identified.

RESULTS

From the reviewed literature, ovarian suppression with gonadotropin-releasing hormone agonists showed promising results in preserving fertility for breast cancer patients undergoing chemotherapy. Additionally, oocyte and embryo cryopreservation demonstrated successful outcomes, with embryo cryopreservation being the most effective option. Notably, the slow-freezing and vitrification methods were both effective in preserving embryos, with vitrification showing superior results in clinical-assisted reproductive technologies. Ovarian tissue cryopreservation emerged as a viable option for prepubertal girls and those unable to undergo conventional ovarian stimulation. The potential of in vitro maturation (IVM) as an alternative method presents a promising avenue for future fertility preservation research.

DISCUSSION

The most suitable treatments for fertility preservation in young patients is the temporary suppression with luteinizing hormone-releasing analogs, while the patient undergoes chemotherapy and cryopreservation. For cryopreservation, the physicians might deem it necessary to either cryopreserve ovarian tissue taken from the patient before any treatment or cryopreserve embryos/oocytes. Cryopreservation of oocytes and/or embryos is the most effective solution for fertility preservation in women of reproductive age, who have a sufficient ovarian reserve and are diagnosed with breast cancer, regardless of the histological type of the tumor. Because approximately 50% of young breast cancer patients are interested in becoming pregnant right after completion of therapy, the evolution and development of fertility preservation techniques promise to be very exciting.

Systematic review and meta-analysis on patented and non-patented vitrification processes to ovarian tissue reported between 2000 and 2021

Due to the great interest in ovarian cryopreservation and, consequently conservation and restoration of female fertility in the last decades, different vitrification procedures (vitrification devices or solutions) have been developed, patented, and used both for academic research purposes and for clinical use. Therefore, the present study aimed to provide a systematic review and meta-analysis of data obtained from the application of different patented and non-patented vitrification devices and solutions in different countries. For this purpose, relevant observational studies published between the years 2000 to 2021 were selected to verify the efficiency of ovarian vitrification processes on parameters such as morphology, viability, and apoptosis in preantral ovarian follicles after transplantation or in vitro culture. Our research revealed that, although several countries were considered in the study, the United States and Japan were the countries that registered the most processes, and 22 and 16 vitrification devices and solutions out of a total of 51, respectively were patented. Sixty-two non-patented processes were also considered in the study in all countries. We also observed that transplantation and in vitro ovarian culture were the techniques predominantly used to evaluate the efficiency of the devices and vitrification solutions, respectively. In conclusion, this review showed that patented or non-patented protocols available in the literature are able to successfully preserve preantral follicles present in ovarian tissue. Despite the satisfactory results reported so far, adjustments in ovarian vitrification protocols in order to minimize cryoinjuries to the follicles remain one of the goals of cryopreservation and preservation of the female reproductive function. We found that vitrification alters the morphology and viability, and offers risks leading in some cases to follicular apoptosis. However, adjustments to current protocols to develop an optimal procedure can minimize damage by not compromising follicular development after vitrification/warming.

Encapsulated Allografts Preclude Host Sensitization and Promote Ovarian Endocrine Function in Ovariectomized Young Rhesus Monkeys and Sensitized Mice

Transplantation of allogeneic donor ovarian tissue holds great potential for female cancer survivors who often experience premature ovarian insufficiency. To avoid complications associated with immune suppression and to protect transplanted ovarian allografts from immune-mediated injury, we have developed an immunoisolating hydrogel-based capsule that supports the function of ovarian allografts without triggering an immune response. Encapsulated ovarian allografts implanted in naïve ovariectomized BALB/c mice responded to the circulating gonadotropins and maintained function for 4 months, as evident by regular estrous cycles and the presence of antral follicles in the retrieved grafts. In contrast to non-encapsulated controls, repeated implantations of encapsulated mouse ovarian allografts did not sensitize naïve BALB/c mice, which was confirmed with undetectable levels of alloantibodies. Further, encapsulated allografts implanted in hosts previously sensitized by the implantation of non-encapsulated allografts restored estrous cycles similarly to our results in naïve recipients. Next, we tested the translational potential and efficiency of the immune-isolating capsule in a rhesus monkey model by implanting encapsulated ovarian auto- and allografts in young ovariectomized animals. The encapsulated ovarian grafts survived and restored basal levels of urinary estrone conjugate and pregnanediol 3-glucuronide during the 4- and 5-month observation periods. We demonstrate, for the first time, that encapsulated ovarian allografts functioned for months in young rhesus monkeys and sensitized mice, while the immunoisolating capsule prevented sensitization and protected the allograft from rejection.

Three-Dimensional Culture for In Vitro Folliculogenesis in the Aspect of Methods and Materials

In vitro ovarian follicle culture is a reproduction technique used to obtain fertilizable oocytes, for overcoming fertility issues due to premature ovarian failure. This requires the establishment of an in vitro culture model that is capable of better simulating the in vivo ovarian growth environment. Two-dimensional (2D) culture systems have been successfully set up in rodent models. However, they are not suitable for larger animal models as the follicles of larger animals cultured in 2D culture systems often lose their shape due to dysfunction in the gap junctions. Three-dimensional (3D) culture systems are more suitable for maintaining follicle architecture, and therefore are proposed for the successful in vitro culturing of follicles in various animal models. The role of different methods, scaffolds, and suspension cultures in supporting follicle development has been studied to provide direction for improving in vitro follicle culture technologies. The three major strategies for in vitro 3D follicle cultures are discussed in this article. First, the in vitro culture systems, such as microfluidics, hanging drop, hydrogels, and 3D-printing, are reviewed. We have focused on the 3D hydrogel system as it uses different materials for supporting follicular growth and oocyte maturation in several animal models and in humans. We have also discussed the criteria used for biomaterial evaluations such as solid concentration, elasticity, and rigidity. In addition, future research directions for advancing in vitro 3D follicle culture system are discussed. Impact statement A new frontier in assisted reproductive technology is in vitro tissue or follicle culture, particularly for fertility preservation. The in vitro three-dimensional (3D) culture technique enhances follicular development and provides mature oocytes, overcoming the limitations of traditional in vitro two-dimensional cultures. Polymer biomaterials have good compatibility and retain the physiological structure of follicles in the 3D culture system. Utilizing hybrid in vitro culture materials by merging matrix, hydrogel, and unique patterned materials may facilitate follicular growth in the future.

Experiences of young girls and women undergoing ovarian tissue cryopreservation: a systematic review and thematic synthesis

The aim of this study was to explore the experiences of young girls and women who underwent or considered ovarian tissue cryopreservation (OTC) using a systematic review of qualitative studies with thematic synthesis framework. Major electronic databases: MEDLINE, EMBASE, the Cochrane Library, CINAHL and PsycINFO were searched from 1946 to May 2020 and reference lists of relevant articles were hand searched. Any studies that described a qualitative inquiry and highlighted the experiences of women with regards to OTC were included. Two independent reviewers screened the title and abstracts and made a selection against inclusion criteria. Main outcomes measures were experiences of women who have considered and/or undergone OTC, decision making in women who underwent or considered OTC and patient education. Nineteen studies were assessed for full text eligibility and four were included in analysis. 144 verbatim quotations from 85 participants in high income countries (UK, USA and Denmark) were included. Two studies adopted grounded theory approach, one phenomenology and one inductive content analysis. Four themes were generated; participants described their experiences as emotional, involving complex decision-making, helping them prepare for the long-term consequences of potentially losing their fertility and hormonal function, as well as their experience being educational. Additionally, the more practical aspects of the procedure such as OTC being invasive as well as costs implications were highlighted. Women and young girls are often involved in making time-sensitive decisions whether or not to undergo OTC. Healthcare professionals involved in the care of young girls and women undergoing this method need to also take into consideration the emotional wellbeing of the patients as well as the time and expertise it requires to help them make an informed decision.

Ovarian Tissue-Based Hormone Replacement Therapy Recovers Menopause-Related Signs in Mice

PURPOSE

In women, menopause manifests with a variety of symptoms related to sex-hormone deficiency. Supplementing steroid hormones with pharmacological drugs has been widely practiced. However, considering the possible complications associated with artificial hormone therapy, studies have been conducted to find an alternative to pharmacological hormone replacement therapy. Accordingly, this study aimed to evaluate the efficacy of tissue-based hormone replacement therapy (tHRT) for treating post-menopausal signs and symptoms.

MATERIALS AND METHODS

CD-1 mice were ovariectomized, and the ovaries were cryopreserved. Following artificial induction of post-menopausal osteoporosis, cryopreserved ovaries were subcutaneously autografted, and indexes related to bone health were monitored for 12 weeks. Bone mineral density (BMD), bone mineral contents (BMC), total bone volume (BV), and body fat mass were measured by dual energy X-ray absorptiometry. Uterine atrophy was assessed histologically, and bone microstructures were imaged by micro-computed tomography analysis.

RESULTS

Regardless of the number of grafted ovaries, the BMC, BMD, and BV values of mice that underwent ovary transplantation were better than those that did not undergo transplantation. The uteruses in these mice were thicker and heavier after auto-transplantation. Furthermore, the bone microstructure recovered after tHRT.

CONCLUSION

Recovery of menopause-related bone loss and uterine atrophy was achieved through tHRT. Ovarian tissue cryopreservation and transplantation may be applicable not only in patients wanting to preserve fertility but also in sex hormone-deficient post-menopausal women.

Age-related fertility decline: is there a role for elective ovarian tissue cryopreservation?

Age-related fertility decline (ARFD) is a prevalent concern amongst western cultures due to the increasing age of first-time motherhood. Elective oocyte and embryo cryopreservation remain the most established methods of fertility preservation, providing women the opportunity of reproductive autonomy to preserve their fertility and extend their childbearing years to prevent involuntary childlessness. Whilst ovarian cortex cryopreservation has been used to preserve reproductive potential in women for medical reasons, such as in pre- or peripubertal girls undergoing gonadotoxic chemotherapy, it has not yet been considered in the context of ARFD. As artificial reproductive technology (ART) and surgical methods of fertility preservation continue to evolve, it is a judicious time to review current evidence and consider alternative options for women wishing to delay their fertility. This article critically appraises elective oocyte cryopreservation as an option for women who use it to mitigate the risk of ARFD and introduces the prospect of elective ovarian cortex cryopreservation as an alternative.

Cryopreservation Methods and Frontiers in the Art of Freezing Life in Animal Models

The development in cryobiology in animal breeding had revolutionized the field of reproductive medicine. The main objective to preserve animal germplasm stems from variety of reasons such as conservation of endangered animal species, animal diversity, and an increased demand of animal models and/or genetically modified animals for research involving animal and human diseases. Cryopreservation has emerged as promising technique for fertility preservation and assisted reproduction techniques (ART) for production of animal breeds and genetically engineered animal species for research. Slow rate freezing and rapid freezing/vitrification are the two main methods of cryopreservation. Slow freezing is characterized by the phase transition (liquid turning into solid) when reducing the temperature below freezing point. Vitrification, on the other hand, is a phenomenon in which liquid solidifies without the formation of ice crystals, thus the process is referred to as a glass transition or ice-free cryopreservation. The vitrification protocol applies high concentrations of cryoprotective agents (CPA) used to avoid cryoinjury. This chapter provides a brief overview of fundamentals of cryopreservation and established methods adopted in cryopreservation. Strategies involved in cryopreserving germ cells (sperm and egg freezing) are included in this chapter. Last section describes the frontiers and advancement of cryopreservation in some of the important animal models like rodents (mouse and rats) and in few large animals (sheep, cow etc).

Why are women considering ovarian tissue cryopreservation to preserve reproductive and hormonal ovarian function? A qualitative study protocol

INTRODUCTION

Current fertility preservation options available to women are oocyte cryopreservation (egg freezing) or embryo cryopreservation. A newer procedure, ovarian tissue cryopreservation (OTC), has become available in some centres, which offers another option for women and girls considering fertility preservation. These procedures are commonly offered to women about to undergo treatments for cancer. OTC involves removing sections of ovarian tissue and cryopreserving it for future reimplantation, often several years later. OTC offers girls and women who may become infertile with optionality and the possibility of pregnancy. OTC has potential for other applications, including restoring ovarian endocrine function beyond biological menopause. This is not without controversy but has led to some women considering undergoing the procedure for purposes of ovarian hormonal preservation (conservation of ovarian endocrine function). OTC is invasive, involves two surgical procedures with concomitant risks and can be costly. Understanding why women may consider and ultimately undergo OTC is timely, so that evidence-based and women-centred care can be provided.

METHODS

A pragmatic narrative qualitative design will be used. A purposive sample of women aged 18-45 who are considering, or have sought, OTC will be recruited over 1-year period. Potential participants will be approached via a clinic that offers OTC on a private basis or via social media.

ANALYSIS

Participant interviews will be audio and, if consented, video recorded. These will be conducted face-to-face or virtually. The recordings will be transcribed verbatim and analysed using a thematic analysis approach supported by NVivo software.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the Institutional Ethical Review ERN_19-1578A. We expect to disseminate the findings of this study through journal articles, conference presentations and multimedia to public.

Parenthood among individuals with Turner syndrome: results of an online survey of attitudes towards pregnancy, adoption, and surrogacy

Choosing a route to parenthood can be a difficult decision for individuals with Turner syndrome, who must consider the unlikely possibility of spontaneous pregnancy, the potential need for assisted reproductive technology such as in vitro fertilization (IVF), and the risks of pregnancy-related complications. In addition, there are other options for parenthood, such as surrogacy and adoption. The perspectives of individuals with Turner syndrome regarding routes to parenthood have not been described in the literature, despite thorough investigation into the feasibility and safety of pregnancy in this population. We conducted a novel online survey of 226 individuals with Turner syndrome to assess their interest in parenthood, their perspectives on available routes to parenthood, and the factors that influence their decision-making. One-quarter of the respondents were already parents, including 54.5% who had achieved pregnancy and 45.5% who adopted. Of those who were not parents, 68.5% expressed a desire to become a parent. Overall, participants had the strongest interest in adoption as a route to parenthood. Interest in adoption was significantly associated with fear of pregnancy-related risks to their health and the health of a future child. Participants also reported interest in pregnancy and IVF. Interest in both pregnancy and IVF were significantly associated with a desire to experience pregnancy and to have a biological child. This study provides important insights into the perspective of individuals with Turner syndrome with respect to building a family and serves as a valuable counseling resource for clinicians facilitating patient decision-making about options for parenthood.

Artificial Ovary for Young Female Breast Cancer Patients

In recent decades, there has been increasing attention toward the quality of life of breast cancer (BC) survivors. Meeting the growing expectations of fertility preservation and the generation of biological offspring remains a great challenge for these patients. Conventional strategies for fertility preservation such as oocyte and embryo cryopreservation are not suitable for prepubertal cancer patients or in patients who need immediate cancer therapy. Ovarian tissue cryopreservation (OTC) before anticancer therapy and autotransplantation is an alternative option for these specific indications but has a risk of retransplantation malignant cells. An emerging strategy to resolve these issues is by constructing an artificial ovary combined with stem cells, which can support follicle proliferation and ensure sex hormone secretion. This promising technique can meet both demands of improving the quality of life and meanwhile fulfilling their expectation of biological offspring without the risk of cancer recurrence.

Effects of AavLEA1 Protein on Mouse Ovarian Tissue Cryopreservation by Vitrification

Conventional ovarian tissue cryopreservation often destroys the structural, functional, and DNA integrity of the ovarian tissue. How to effectively retain the ultrastructure and subsequent function of ovarian tissue during cryopreservation has long been an issue of concern. Late embryogenesis abundant (LEA) proteins are a class of highly hydrophilic proteins and have been reported to protect various cells from water stress. However, whether LEA proteins exert protective effects on ovarian tissue cryopreservation remains unknown. To investigate the benefit of LEA proteins in ovarian tissue cryopreservation, we purified the recombinant AavLEA1 protein, a member of Group 3 LEA proteins, then cryopreserved the mouse ovaries with this protein by vitrification, and obtained the ovarian follicle structure, cellular proliferation, apoptosis, and GAPDH gene expression of postcryopreservation ovaries. We found that recombinant AavLEA1 protein protected the ovarian follicles from cryoinjury, improved the proliferative ability of follicles, decreased the apoptosis, and promoted the GAPDH gene expression. These results indicated that the LEA protein enhanced the antiapoptosis ability of ovarian cells and retained DNA/RNA integrity against cryoinjury during ovarian tissue vitrification. LEA proteins exert beneficial effects on ovarian tissue cryopreservation, and maybe provide a novel cryoprotective agent for ovarian tissue cryopreservation.

Two-Decade Experience of Royan Institute in Obtaining Mature Oocyte from Cryopreserved Ovarian Tissue: In Vitro and In Vivo Approaches

Ovarian tissue cryopreservation (OTC) holds promise for preservation of fertility among women who have lost their fertility due to diseases such as cancer. OTC has significantly assisted such cases by helping them maintain normal hormonal levels and menstrual cycles. Appropriate strategies to develop and extract mature oocytes from OTC could overcome a range of complications that are associated with ovarian dysfunction, caused by aging, and primary or secondary ovarian insufficiency. Scientists from different departments at The Royan Institute (Tehran, Iran) have been conducting studies to find the best way to extract mature oocytes from animal and human cryopreserved ovarian tissues. The various studies conducted in this area in the past 20 years, by researchers of the Royan Institute, are collated and provided in this review, in order to provide an idea of where we are now in the area of fertility preservation.

Infertility cell therapy and epigenetic insights

Recent advances in assisted reproductive technology (ART) have allowed couples with severe infertility to conceive, but the methods are not effective for all cases. Stem cells as undifferentiated cells which are found in different stages of embryonic, fetal and adult life are known to be capable of forming different cell types, tissues, and organs. Due to their unlimited resources and the incredible power of differentiation are considered as potential new therapeutic biological tools for treatment of infertility. For reproductive medicine, stem cells are stimulated in vitro to develop various specialized functional cells including male and female gametes. The epigenetic patterns can be modified in the genome under certain drugs exposure or lifestyle alterations. Therefore, epigenetics-related disorders may be treated if the nature of the modifications is completely admissible. It is proved that our understanding of epigenetic processes and its association with infertility would help us not only to understand the etiological factors but also to treat some type of male infertilities. Exploration of both genetic and epigenetic variations in the disease development could help in the identification of the interaction patterns between these two phenomena and possible improvement of therapeutic methods.

Advances in the applications of polymer biomaterials for in vitro follicle culture

The ovarian reserve (OR) indicates ovarian function by representing the quantity and quality of ovarian follicles, and it gradually decreases with increasing age. With the prolongation of women's lives, the protection provided by estrogen is lost for decades in postmenopausal women, and the related cardiovascular and cerebrovascular diseases, osteoporosis, and decreased immunity are the main risk factors affecting women's quality of life and longevity. Pharmacologic hormone replacement therapy (PHRT) has been controversial, and the construction of artificial ovary (AO) has attracted increasing attention. The most critical step of AO generation is the establishment of an in vitro culture (IVC) system to support the development of isolated follicles. This article mainly compares the advantages and disadvantages of different polymer biomaterials for use in follicle IVC, provides theoretical support for the development and construction of the follicle IVC system using natural biological materials, and provides a theoretical basis for establishing mature AO technology.

Delaying Reproductive Aging by Ovarian Tissue Cryopreservation and Transplantation: Is it Prime Time?

Ovarian tissue cryopreservation and autotransplantation can restore ovarian endocrine function and fertility and recently were changed from experimental to fertility preservation procedures for medical indications by the American Society of Reproductive Medicine. Such advances have resulted in discussions around the utility of ovarian cryopreservation in healthy women to preserve fertility and delay menopause or as a hormone replacement approach. Such 'elective' use of ovarian tissue cryopreservation requires a risk-benefit assessment. Here, we review evidence for and against the utility of ovarian tissue harvesting in healthy women, scrutinize recent and needed advances to enhance the feasibility of such an approach, and provide practice and future research guidelines.

Burning Questions in the Oncofertility Counseling of Young Breast Cancer Patients

The improved prognosis of breast cancer patients makes survivorship issues an area of crucial importance. In this regard, an increased attention is needed toward the development of potential anticancer treatment-related long-term side-effects, including gonadal failure and infertility in young women. Therefore, fertility preservation and family planning are crucial issues to be addressed in all young women of reproductive age with newly diagnosed cancer. Despite a growing availability of data on the efficacy and safety of fertility preservation options and the fact that conceiving after prior history of breast cancer has become more accepted over time, there are still several gray zones in this field so that many physicians remain uncomfortable to deal with these topics. The purpose of this review is to answer some of the most controversial questions frequently asked by patients during their oncofertility counseling, in order to provide a detailed and up-to-date overview on the evidence available in this field to physicians involved in the care of young women with breast cancer.

Ovarian tissue cryopreservation and transplantation to delay menopause: facts and fiction

Ovarian tissue cryopreservation and transplantation (OTCT) is increasingly being used in young cancer patients for fertility restoration and prevention of premature ovarian insufficiency (POI) and has recently been advocated as a method to delay menopause. This is accomplished by cryopreserving ovarian tissue that is excised laparoscopically in thin pieces at a young age. Cryopreserved tissue will be transplanted at menopause, when ovarian function is no longer present. Transplantation may need to be repeated several times to achieve long-term restoration of ovarian function. However, it is unknown whether ovarian grafts result in a normal steroid pulsatile secretion, similar to that present during reproductive years. In addition, it is not known whether the need to restore ovarian activity appears earlier in women who undergo OTCT to delay menopause, although indirect data suggest that this is likely to be true. Until today, no cohort or comparative studies evaluating OTCT as a potential alternative to hormone replacement therapy (HRT) have been published and, thus, there is no evidence to suggest that OTCT is superior to HRT in terms of both efficacy and safety. Given the availability of alternative, established treatments for managing menopausal symptoms, as well as the multiple unanswered questions regarding the method, it is imperative that, before OTCT is regarded as a mainstream technique for management of menopausal symptoms, further evaluation and clinical investigation are undertaken.

First pregnancy and live birth in Turkey following frozen-thawed ovarian tissue transplantation in a patient with acute lymphoblastic leukemia who underwent cord blood transplantation

PURPOSE

To report the first live birth after frozen-thawed ovarian transplantation in Turkey and the second case for an acute lymphoblastic leukemia (ALL) survivor in the world.

METHODS

A 19-year-old patient underwent ovarian tissue cryopreservation (OTC) before cord blood transplantation in 2010. She was diagnosed as ALL with a bone marrow biopsy revealing 90% blast ALL-L2 type, and karyotype analyses indicated reciprocal translocation at t(9;22)(q34;q11). The patient received the Berlin-Frankfurt-Munster (BFM) protocol, and complete remission was achieved before fertility preservation. Serum AMH level was measured as 1.5 ng/ml, and 12 antral follicles were counted on ultrasound. She was informed about fertility preservation options and decided to proceed with OTC, with her signed consent before cord blood transplantation in April 2011. Ovarian tissue transplantation (OTT) was performed in 2017 when the patient was menopausal with serum FSH levels > 100 IU/ml and estradiol < 20 pg/ml and hematologically in molecular remission. Detailed molecular analysis, standard histology, and immunohistochemistry demonstrated that the thawed tissue is free of malignant cells.

RESULTS

Six months following OTT, she had spontaneous menstruation with serum FSH 11 IU/ml and estradiol 53 pg/ml. Two consecutive IVF cycles yielded three top-quality embryos. Following three embryo transfer cycles, one fresh and two frozen, a healthy term live birth was achieved. Frozen-thawed-transplanted tissues were extracted during caesarean delivery upon the patient's request after a total period of 25 months in vivo, and histopathological evaluation revealed that the tissue was free of leukemic infiltration.

CONCLUSION

The authors report the first pregnancy and live birth in Turkey and the second live birth in the world following transplantation of frozen-thawed ovarian tissue in a leukemia survivor. As the transplanted tissues were removed during caesarean delivery, histological findings prove the functionality and the malignant-free status of the transplanted tissue during the grafted period.

Oocyte or ovarian tissue banking: decision-making in women aged 35 years or older facing age-related fertility decline

RESEARCH QUESTION

Women who face age-related fertility decline have the option to safeguard future reproductive potential by banking oocytes or ovarian tissue. What are the methods that women prefer and what factors are important in their decision-making?

DESIGN

Qualitative interview study, participants were recruited through monthly information sessions at a university hospital on oocyte banking, postings on social media, websites and newsletters and snowball sampling. Women had to be aged 35 years or older, single, childless and with a possible future desire for motherhood. Key concepts of the Health Belief Model were used as framework for the analyses.

RESULTS

In total, 15 women participated in this qualitative study. For oocyte banking, they mentioned chances of success, extra time and faith in the technique and healthcare professionals as benefits. Risks for themselves or future children and costs were considered to be barriers in decision making. For ovarian tissue banking, the chances of success, the possibility of natural conception, the time investment and effect on menopausal symptoms were seen as benefits, and lack of experience and lack of information were considered barriers for themselves or their future children. Overall, they considered the procedures involved in oocyte banking as relatively 'easy', whereas ovarian tissue banking was seen as a more invasive procedure.

CONCLUSION

Most women preferred oocyte banking over ovarian tissue banking because of its relative convenience. Future quantitative research in a larger cohort is necessary to confirm the findings and provide more insight into the relative importance of the different factors influencing women's decision.

Influence of microwave-assisted dehydration on morphological integrity and viability of cat ovarian tissues: First steps toward long-term preservation of complex biomaterials at supra-zero temperatures

Ovarian tissue contains large pools of immature oocytes enclosed in primordial follicles, making it an attractive target for fertility preservation in female cancer patients, livestock and wild species. Compared to cryopreservation, desiccation and long-term storage of samples at supra-zero temperatures (using strategies inspired from small organisms to resist extreme environments) would be more cost-effective and convenient. The objective of the study was to characterize the influence of microwave-assisted dehydration on structural and functional properties of living ovarian tissues. While this method allows preservation of single cells (cat oocytes and sperm cells so far) using trehalose as the xeroprotectant, it has not been developed for multicellular tissues yet. Ovarian cortex biopsies were reversibly permeabilized, exposed to various concentrations of trehalose, and dried for different times using a commercial microwave under thermal control. Effective dehydration of samples along with proper trehalose retention were reached within 30 min of microwave drying. Importantly, the process did not affect morphology and DNA integrity of follicles or stromal cells. Moreover, transcriptional activity and survival of follicles were partially maintained following 10 min of drying, which already was compatible with storage at non-cryogenic temperatures. Present data provide critical foundation to develop dry-preservation techniques for long-term storage of living multicellular tissues.

Encapsulation of ovarian allograft precludes immune rejection and promotes restoration of endocrine function in immune-competent ovariectomized mice

Premature ovarian insufficiency (POI) is a significant complication of cytotoxic treatments due to extreme ovarian sensitivity to chemotherapy and radiation. POI is particularly devastating for young girls reaching puberty, because it irreversibly affects their physical and cognitive development. Changes occurring during puberty determine their height, bone health, insulin responsiveness, lipid metabolism, cardiovascular health and cognition. The only available treatment for POI during puberty is hormone replacement therapy (HRT), which delivers non-physiological levels of estrogen, lacks other ovarian hormones and pulsatility, and is not responsive to feedback regulation. Here we report that ovarian allografts encapsulated in a hydrogel-based capsule and implanted in ovariectomized mice restore ovarian endocrine function in immune competent mice. Ovarian tissue from BALB/c mice was encapsulated in poly(ethylene-glycol) (PEG) hydrogels, with a proteolytically degradable core and a non-degradable shell. The dual capsules were implanted subcutaneously in immune competent ovariectomized C57BL/6 mice for a period of 60 days. As expected, non-encapsulated ovarian allografts implanted in a control group sensitized the recipients as confirmed with donor-specific IgG in the serum, which increased 26-fold in the 3 weeks following transplantation (p = 0.02) and infiltration of the graft with CD8 T cells consistent with allo-immunity. In contrast, encapsulation in the Dual PEG capsules prevented sensitization to the allograft in all the recipients with no evidence of lymphocytic infiltration. In summary, the approach of hydrogel-based immunoisolation presents a minimally invasive and robust cell-therapy to restore hormonal balance in ovarian insufficiency. This report is the first to demonstrate the application of a tunable PEG-based hydrogel as an immunoisolator of allogeneic ovarian tissue to restore endocrine function in ovariectomized mice and prevent cell-mediated immune rejection in immune competent mice.

Radiofrequency identification tag system improves the efficiency of closed vitrification for cryopreservation and thawing of bovine ovarian tissues

PURPOSE

A radiofrequency identification (RFID) tag system was designed to streamline cryopreservation and thawing procedures. This study evaluated the usefulness of the RFID tag system for improving the efficiency of cryopreserving/thawing bovine ovarian tissue by the closed vitrification protocol.

METHODS

Six participants carried out closed vitrification and thawing of bovine ovarian tissues procedures using either the conventional or the new RFID tag method, and the time required to perform each step of the respective methods was measured. After normality of data was confirmed by the Shapiro-Wilk test, the significance of differences was assessed by the unpaired t test.

RESULTS

When closed vitrification was performed, the time required for each step showed a significant difference between the two methods (t(4) = 2.938, p = 0.042, d = 2.40), and the total cryopreservation time was 11 min shorter using the RFID tag system. When thawing was performed, the time required for each step also showed a significant difference between the two methods (t(4) = 2.797, p = 0.049, d = 2.28), and the total thawing time was 2 min shorter using the RFID tag system.

CONCLUSION

The RFID tag system tested in this study seems to be suitable for managing biological samples stored in liquid nitrogen. Adoption of an RFID tag system by fertility centers may not only improve the efficiency of cryopreserving/thawing reproductive tissues but could also reduce human error.

Importance of ovarian tissue cryopreservation in fertility preservation and anti-aging treatment

Various oncological and non-oncological diseases, as well as their treatments, can cause premature ovarian insufficiency and reduce a woman's reproductive potential. Fertility preservation is, therefore, becoming an emerging field of reproductive medicine allowing these patients to have their own biological children. The aim of this review is to analyze the importance of ovarian tissue cryopreservation as a fertility preservation method as well as its new role as a hormone replacement treatment. Although ovarian tissue cryopreservation is currently regarded as an experimental procedure, it is rapidly advancing and may become an established fertility preservation method in the near future. This method does not require ovarian stimulation or a subsequent delay in the initiation of cancer treatment. Furthermore, orthotopic ovarian tissue transplantation offers the unique opportunity of spontaneous conception. Due to the restoration of endocrine function following the procedure, ovarian tissue cryopreservation may also be used as tissue hormone replacement therapy in cases of premature ovarian insufficiency, to postpone menopause and prevent its troublesome symptoms and diseases. Even though the role of ovarian tissue cryopreservation as a new anti-aging treatment modality is quite promising, the safety and efficacy of this approach should be investigated in clinical settings.

Ovarian tissue cryopreservation in prepubertal patients with oncological diseases: multidisciplinary approach and outcomes

In children with cancer, the issues related to the quality of life are becoming increasingly important together with the improvement of survival rates. This creates an entirely new challenge - minimizing the toxicity of the antitumor therapy without reducing its effectiveness. One of the specific side effects of the antitumor therapy is gonadotoxicity, which negatively affects both the somatic and mental state of the survivors. Since ovarian stimulation is ineffective in prepubertal patients, ovarian tissue cryopreservation (OTC) remains the most promising option to preserve fertility. The primary goal of this publication is to emphasize the importance of the reproductive health problem in girls with oncological diseases, with a description of the current data of international literature on the prospects of OTC in order to preserve fertility. Another goal is to present a multidisciplinary strategy for the management of prepubertal age patients with the oncological disease within the framework of the Oncological Fertility Project at Almazov National Medical Research Center. Based on the data of Russian and international literature, as well as existing guidelines and recommendations on reproductive health, a single algorithm for selecting patients has been developed, considering the expected gonadal toxicity for the use of the OTC in prepubertal girls. The developed algorithm allows identifying patients of prepubertal age, requiring the use of new possibilities of reproductive technologies. In a long-term date, we are planning to evaluate the effectiveness of the orthotopic reimplantation technique of the cryopreserved ovarian tissue in restoring the reproductive function. A multidisciplinary team of specialists and the possibilities of the Federal Center facilitate implementing the Oncofertility Program in routine practice for girls and young women, receiving gonadotoxic treatment.

Ovarian Tissue Transplantation: Experience From Germany and Worldwide Efficacy

Extraction of ovarian tissue prior to oncologic therapy and subsequent transplantation is being performed increasingly often to preserve fertility in women. The procedure can be performed at any time of the cycle and, therefore, generally does not lead to any delay in oncological therapy. Success rates with transplantation of cryopreserved ovarian tissue have reached promising levels. More than 130 live births have been reported worldwide with the aid of cryopreserved ovarian tissue and the estimated birth rate is currently approximately 30%. In Germany, Austria, and Switzerland, the FertiPROTEKT consortium has successfully achieved 21 pregnancies and 17 deliveries generated after 95 ovarian tissue transplantations by 2015, one of the largest case series worldwide confirming that ovarian tissue cryopreservation and transplantation are successful. Approximately, more than 400 ovarian tissue cryopreservation procedures are performed each year in the FertiPROTEKT consortium, and the request and operations for ovarian tissue transplantation have increased in recent years. Therefore, recommendations for managing transplantation of ovarian tissue to German-speaking reproductive medicine centers were developed. In this overview, these recommendations and our experience in ovarian tissue transplantation are presented and discussed with international procedures.

Isolation of female germline stem cells from porcine ovarian tissue and differentiation into oocyte-like cells

Historically, it had been widely accepted that the female mammalian ovary contained a limited number of oocytes that would reduce over time, without the possibility of replenishment. However, recent studies have suggested that female germline stem cells (FGSCs) could replenish the oocyte-pool in adults. The aim of this study was to isolate FGSCs from porcine ovaries and differentiate them into oocyte-like cells (OLCs). The FGSCs were successfully isolated from porcine ovarian tissue and cultured in vitro, in DMEM/F-12 medium supplemented with growth factors (EGF, FGF, GDNF, etc.) and a supplement (N21). These cells possessed spherical morphology and expressed specific germline characteristics (Vasa, Stella, Oct4, c-kit). By evaluating different conditions for in vitro differentiation of FGSCs, co-culturing the isolated FGSCs with MEF cells, under three-dimensional (3D) cell cultures, were shown to be optimal. FGSCs could successfully be differentiated into OLCs and reached about 70 µm in diameter, with a large number of surrounding somatic cells. Importantly, OLCs contained large nuclei, about 25–30 µm, with filamentous chromatin, similar to oocyte morphology, and expressed oocyte-specific markers (Gdf9, Zp2, SCP3, etc.) at the same level as oocytes. In conclusion, we successfully isolated FGSCs from porcine ovarian tissue and differentiated them into oocyte-like cells. This will provide a valuable model for studying a new, alternative source of oocytes.

FertiPROTEKT, Oncofertility Consortium and the Danish Fertility-Preservation Networks - What Can We Learn From Their Experiences?

Fertility preservation is an increasingly important discipline. It requires close coordination between reproductive medicine specialists, reproductive biologists, and oncologists in various disciplines. In addition, it represents a particular health policy challenge, since fertility-protection measures are to be understood as a treatment for side effects of gonadotoxic treatments and would therefore normally have to be reimbursed by health insurance companies. Therefore, it is inevitable that fertility-preservation activities should organise themselves into a network structure both as a medical-logistic network and as a professional medical society. The necessary network structures can differ significantly at regional, national, and international level, as the size of the regions to be integrated and the local cultural and geographical conditions, as well as the political conditions are very different. To address these issues, the current review aims to point out the basic importance and the chances but also the difficulties of fertility-protection networks and give practical guidance for the development of such network structures. We will not only discuss network structures theoretically but also present them based on three established, different sized networks, such as the Danish Network (www.rigshospitalet.dk), representing a centralised network in a small country; the German-Austrian-Swiss network FertiPROTEKT® (www.fertiprotekt.com), representing a centralised as well as decentralised network in a large country; and the Oncofertility® Consortium (www.oncofertility.northwestern.edu), representing a decentralised, internationally oriented network, primarily serving the transfer of knowledge among its members.

Adipose-derived stem cells promote survival, growth, and maturation of early-stage murine follicles

BACKGROUND

Premature ovarian insufficiency is a common complication of anticancer treatments in young women and girls. The ovary is a complex, highly regulated reproductive organ, whose proper function is contingent upon the bidirectional endocrine, paracrine, and autocrine signaling. These factors facilitate the development of the follicles, the functional units of the ovary, to progress from the gonadotropin-independent, paracrine-controlled early stage to the gonadotropin-dependent, endocrine-controlled later stage. We hypothesized that the low survival rate of individually cultured early-stage follicles could be improved with co-culture of adipose-derived stem cells (ADSCs) that secrete survival- and growth-promoting factors.

MATERIALS AND METHODS

Ovarian follicles ranging from 85 to 115 μm in diameter, from 10- to 12-day-old B6CBAF1 mice were mechanically isolated and co-encapsulated with ADSCs within alginate-based 3D culture system. The follicles were cultured for 14 days, imaged using light microscopy every 2 days, and matured at the end. Follicle media were changed every 2 days and collected for hormone measurements. Follicle diameter, morphology, number of transzonal projections, and survival and maturation rates were recorded. Statistical analyses using one- and two-way ANOVA were performed to compare hormone levels, survival of the follicles and ADSCs, oocyte maturation rates, and follicle growth.

RESULTS

The co-encapsulation of the follicles with ADSCs increased follicle survival, ranging from 42.4% for the 86-95 μm to 86.2% for the 106-115-μm follicle size group. Co-culture also improved the follicle growth, the rate of antrum formation and oocyte maturation compared to the follicles cultured alone. The levels of androstenedione, estradiol, and progesterone of co-encapsulated follicles increased progressively with time in culture.

CONCLUSIONS

To our knowledge, this is the first report of an in vitro system utilizing mouse adipose-derived stem cells to support the development of the mouse follicles. Our findings suggest that co-encapsulation of ADSCs with early-stage follicles supports follicular development, through secretion of cytokines that promote follicular survival, antrum formation, and meiotic competence. The unique 3D culture system that supports the survival of both cell types has translational implications, as ADSCs could be used as an autologous source for in vitro maturation of early-stage human follicles.

A prospective study of women and girls undergoing fertility preservation due to oncologic and non-oncologic indications in Sweden-Trends in patients' choices and benefit of the chosen methods after long-term follow up

INTRODUCTION

In Scandinavian countries, programs for fertility preservation are offered free of charge at tertiary-care university hospitals to all patients facing treatments with risk of subsequent sterility. In this prospective study we aimed to investigate trends in female patients' choices after counseling and fertility preservation outcomes during follow up in relation to benign vs malignant indications.

MATERIAL AND METHODS

Data on 1254 females including 1076 adults and 178 girls who received fertility preservation counseling for either oncologic (n = 852) or benign indications (n = 402) at Karolinska University Hospital, Stockholm, between 1 October 1998 and 1 December 2018 were analyzed. As appropriate, t tests and chi-square tests were used to compare groups. Logistic regression was used to compare outcomes among groups depending on indications.

RESULTS

Adult women generally elected to undergo oocyte retrieval after controlled ovarian stimulation for cryopreservation of embryos or oocytes (n = 538, 73%), whereas a minor proportion opted for cryopreservation of ovarian tissue retrieved through laparoscopy (n = 221, 27%). More than half of the women with a partner chose either not to fertilize their oocytes aiming at cryopreservation of oocytes or to share obtained oocytes attempting both cryopreservation of oocytes and cryopreservation of embryos. All pre-pubertal (n = 48) and 73% of post-pubertal girls (n = 66) elected cryopreservation of ovarian tissue. In recent years, an increasing number of teenagers have opted for controlled ovarian stimulation aiming at cryopreservation of oocytes, either before (n = 24, 17%) or after completion of cancer treatment (n = 15, 10%). During follow up, 27% of the women returned for a new reproductive counseling, additional fertility preservation or to attempt pregnancy. Utilization rates among individuals who were alive and of childbearing age by December 2018 indicated 29%, 8% and 5% for embryos, oocytes and ovarian tissue with live birth rates of 54%, 46% and 7%, respectively. Women with benign indications were significantly younger than women with previous malignant indications at the time of attempting pregnancy. Although the pregnancy rates were similar among both groups, the live birth rate was significantly higher in women with benign vs previous malignant indications (47% vs 21%, P = .002).

CONCLUSIONS

Trends in fertility preservation choices have changed over time. Women with previous malignancy had lower live birth rates than women with benign fertility preservation indications.

Time from referral to ovarian tissue cryopreservation in a cohort of Danish women

INTRODUCTION

Young women with a cancer diagnosis often have very little time to decide whether or not to commence fertility-preserving strategies before initiating potentially sterilizing cancer treatment. Minimizing the interval from opting for fertility preservation to completion of the procedure will reduce the potential risk of delaying cancer treatment. In the current study, we have evaluated the period of time from referral to ovarian tissue cryopreservation (OTC) to actual freezing of the tissue in a cohort of Danish women.

MATERIAL AND METHODS

The study population comprised 277 consecutive patients with both malignant and nonmalignant diseases referred for OTC from four centers in the Danish network. Statistical analysis was conducted to analyze the impact of age, diagnosis, and referring center on the time from OTC-referral to OTC. A literature search for "random start" protocols for controlled ovarian stimulation (COS) for fertility preservation in cancer patients was performed.

RESULTS

The time from OTC-referral to OTC was significantly influenced by diagnosis, age, and referring center. Women with malignant diseases other than breast cancer, such as sarcomas, pelvic cancers, and hematological cancers, experienced a significantly shorter interval to OTC (5 days) than women with breast cancer (7 days) and nonmalignant diseases including systemic, ovarian, and hereditary conditions (13-17.5 days). Women over the age of 30 years experienced a significantly longer time to OTC (P < 0.03), and the diagnosis determined the length of the interval (P < 0.001). According to the literature, fertility preservation by oocyte vitrification requires 13-14 days, as the average time for 1 round of COS was 11 days and oocyte collection can be performed 2 days later.

CONCLUSIONS

It is in the interest of both cancer patients and clinicians to perform fertility preservation as quickly and safely as possible. In a Danish setting, OTC provides a short interval of around 6 days from the patient choosing this option to completion of the procedure. This is considerably less time than what is needed to perform COS and oocyte vitrification, and therefore OTC might be considered the preferred choice of fertility preservation when urgency is needed.