Successful in Vitro Fertilization and Embryo Transfer after Transplantation of Cryopreserved Ovarian Tissue: Report of the First Korean Case

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.

History of fertility preservation

Background: Fertility preservation refers to a procedure performed to maintain the ability to become pregnant before receiving treatment with a risk of fertility loss, such as chemo- or radiation therapy. Examples of fertility-preserving procedures include freezing, sperm freezing, embryo freezing through in vitro fertilization, and ovarian tissue freezing.Current Concepts: Until the late 1990s, awareness of fertility preservation among clinicians and patients was relatively low, and the only way to preserve and restore fertility in women with cancer was the cryopreservation of embryos. However, as the survival rate of cancer patients increased and the treatment results of various diseases improved, interest in quality of life such as pregnancy and childbirth after treatment gradually increased, and became a driving force for the development of fertility preservation. In the 2000s, several centers began cryopreserving ovarian tissue, including primordial follicles from young patients before chemotherapy. Currently, ovarian tissue cryopreservation can be used in combination with in vitro maturation and egg vitrification techniques. Novel methods to improve follicle survival after transplantation are currently being investigated. Methods to improve follicle survival after transplantation and new ovarian protective agents to protect the ovaries from cytotoxic agents are currently being studied.Discussion and Conclusion: Advances in fertility-preserving technologies in the future will contribute to the delivery of healthy children by providing tailored treatments and more individualized fertility-preserving strategies to patients whose fertility is at risk.

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.

The Experience of Fertility Preservation in a Single Tertiary Center in Korea

OBJECTIVE

Oocyte (OC), embryo (EC), and ovarian tissue cryopreservation (OTC) are options for fertility preservation (FP) before going through gonadotoxic cancer treatment, or anticipated fertility decline in benign ovarian diseases, or for planned OC. The aim of this study is to report outcomes of FP in a single tertiary hospital in Korea.

METHODS

This is a retrospective study of OC, EC, and OTC cycles. All patients who visited or were referred to the infertility clinic at the Department of Obstetrics and Gynecology for the purpose of FP between 2010 and October 2021 were included.

RESULTS

A total of 564 controlled ovarian stimulation cycles were conducted in 416 women. Three hundred fifty-seven women underwent 494 OC cycles. Most patients were diagnosed with breast cancer (22.4%), followed by endometriomas (21.9%), and then by planned OC (20.7%). Cases of OC have increased over the years, peaking at 109 cycles in 2019 compared to one in 2010. Fifty-nine women underwent 70 EC cycles, and breast cancer (50.8%) was the most common indication. Repetitive OC and EC cycles were undergone in 92 and 9 women, respectively (mean number of repetition, 1.37 and 1.19 times in OC and EC, respectively), yielding a maximum number of 33 oocytes or 23 embryos being cryopreserved per patient. The utilization rate was 3.1% (11/357) in OC and 16.9% (10/59) in EC. Twenty-six women underwent OTC, and gynecologic cancer was the most common indication (9/26, 34.6%). One woman had the cryopreserved ovarian tissue retransplanted and successfully generated embryos.

CONCLUSION

OC, EC, and OTC are possible options for preserving fertility, and these opportunities should be provided for women at risk of fertility decline or those who are eager to protect their future fertility. This is the first report on long-term FP outcomes in a single tertiary center in Korea. We expect that there will be more cases over the years and more women returning to use their gametes or embryos for pregnancy.

Efficacy of assisted reproductive technology after ovarian tissue transplantation in a cohort of 11 patients with or without associated infertility factors

PURPOSE

IVF treatment in women with grafted frozen-thawed ovarian tissue is associated with poor reproductive outcomes. The aim of this study was to evaluate the efficacy of ovarian tissue transplantation (OTT) followed by assisted reproductive technology (ART) in women with or without associated infertility factors.

METHODS

This is a prospective cohort study with retrospective data collection including eleven women, four of whom having an infertility factor (IF), who had undergone OTT in one university center between 2005 and 2017, followed by ART in six in vitro fertilization (IVF) centers.

RESULTS

In total, 25 of the 85 cycles initiated (29%) were canceled, resulting in 60 oocyte retrievals. Ninety-five oocytes were retrieved: 36 were abnormal or immature, 29/39 fertilized (74%) after ICSI and 13/20 (65%) after IVF. Thirty-five embryos were transferred in seven patients (5/7 patients without IF and 2/4 patients with IF). After ART, one patient with IF experienced two pregnancies, one resulting in a live birth. For all patients, pregnancy rates and live birth rates were 7.4% and 3.7% per embryo transfer, respectively. Nine pregnancies and four live births occurred after spontaneous conception in five patients without IF, none in the infertility group.

CONCLUSION

This study confirms that IVF treatment in women with grafted frozen-thawed ovarian tissue is associated with poor outcomes. However, the chances of natural conception are high in women without IF. Patients with IF, without the possibility of spontaneous pregnancy, should be informed of poor reproductive outcomes after OTT followed by ART.

TRIAL REGISTRATION NUMBER

NCT02184806.

Cryostorage and retransplantation of ovarian tissue as an infertility treatment

While still considered an experimental procedure in most countries, ovarian tissue cryopreservation and transplantation has been increasingly applied worldwide to restore fertility in patients with malignant and non-malignant pathologies with risk of premature ovarian insufficiency. It has yielded more than 130 live births up to now and almost all transplanted patients recovered their ovarian function. This study summarizes ovarian tissue cryopreservation and transplantation indications, procedures, their efficacy and main results and proposes different strategies to improve this strategy. Although the main focus of this study is on ovarian tissue cryopreservation and transplantation as a strategy to restore fertility, we believe that it is also important to discuss other applications for this approach.