A comprehensive review and update on human fertility cryopreservation methods and tools

What is driving the global decline of human fertility? Need for a multidisciplinary approach to the underlying mechanisms

An intense period of human population expansion over the past 250 years is about to cease. Total fertility rates are falling dramatically all over the world such that highly industrialized nations, including China and the tiger economies of SE Asia, will see their populations decline significantly in the coming decades. The socioeconomic, geopolitical and environmental ramifications of this change are considerable and invite a multidisciplinary consideration of the underlying mechanisms. In the short-term, socioeconomic factors, particularly urbanization and delayed childbearing are powerful drivers of reduced fertility. In parallel, lifestyle factors such as obesity and the presence of numerous reproductive toxicants in the environment, including air-borne pollutants, nanoplastics and electromagnetic radiation, are seriously compromising reproductive health. In the longer term, it is hypothesized that the reduction in family size that accompanies the demographic transition will decrease selection pressure on high fertility genes leading to a progressive loss of human fecundity. Paradoxically, the uptake of assisted reproductive technologies at scale, may also contribute to such fecundity loss by encouraging the retention of poor fertility genotypes within the population. Since the decline in fertility rate that accompanies the demographic transition appears to be ubiquitous, the public health implications for our species are potentially devastating.

DNA fragmentation, antioxidant activity and histological structure of cryopreserved testicular tissue depending on sexual maturity and immunological status

The objective of this work was to determine a relationship between a frequency of DNA fragmentation, a level of antioxidant activity and a preservation of histological structure depending on initial status of fragments of seminiferous tubules of testes (FSTT) of rats at the stages of cryopreservation. FSTT of animals of different ages (immature, mature), as well as animals with changed immunological status (adjuvant arthritis) were cryopreserved. Slow uncontrolled freezing was used in a cryomedium of fibrin gel with 0.7 M glycerol. The results showed that viability, TAS, γGGT and G6PD activities had the highest values in the group of intact immature animals both in fresh FSTT and after exposure to cryomedium or cryopreservation, while the indexes of DNA fragmentation and ROS content had the lowest values. It was found that an increase in the DNA fragmentation rate occurred in parallel with a decrease in the values of antioxidant activity and membrane integrity. The spermatogenenic epithelium after cryopreservation differed between the groups in a relative number of cells with pathologically changed nuclei and the frequency of exfoliation of epithelial cells into the tubule cavity namely, there was a tendency to an increase in the damaging effects in the series, "Immature → Sexually mature → Autoimmune arthritis". The obtained data can be taken into account in the development of low-temperature preservation protocols using cryotechnologies, which will ensure the maintenance of the morphological and functional characteristics of FSTT depending on sexual maturity and immunological status.

Perceptions and experiences of fertility preservation in female patients with cancer in Greece

BACKGROUND

As advances in oncology have led to remarkable and steady improvements in the survival rates of patients with cancer and anticancer treatment can cause premature ovarian failure in women, fertility preservation (FP) has become a global public health concern and an integral part of the care for women diagnosed with cancer during reproductive age. However, for various reasons, FP remains underutilized for patients with cancer. There are substantial gaps in our knowledge about women's experiences and perceptions of the issue. This study aims to contribute to bridging that gap.

METHODS

This prospective qualitative study was conducted from March 2018 to February 2023. A combination of purposive and snowball sampling was used. Data were collected by semistructured interviews with nineteen reproductive-age women who had been recently diagnosed with cancer. Data were classified and analysed with a thematic analysis approach.

RESULTS

A variety of distinct themes and subthemes emerged from the analysis of the interview data. The cancer diagnosis emerged as a factor that considerably affects the women's attitudes towards biological parenthood: It can further increase their (strong) previous desire or decrease their previous (weak) desire. Women with a recent cancer diagnosis had not received adequate and multidisciplinary counselling, including clear and sufficient information. However, participants felt satisfied with the information they received because they either received the information they requested or remained in denial about the need to be informed (i.e., because they felt overwhelmed after the cancer diagnosis). Embryo cryopreservation emerged as a less desirable FP option for women with cancer. Participants showed respect for human embryos, not always for religious reasons. Surrogacy emerged as the last resort for most participants. Religious, social or financial factors did play a secondary (if any) role in women's decision-making about FP. Finally, male partners' opinions played a secondary role in most participants' decision-making about FP. If embryo cryopreservation was the selected option, partners would have a say because they were contributing their genetic material.

CONCLUSIONS

The findings that emerged from the data analysis were partly consistent with prior studies. However, we identified some interesting nuances that are of clinical importance. The results of this study may serve as a starting point for future research.

Feasibility and efficiency of delayed ovarian stimulation and metaphase II oocyte banking for fertility preservation and childbearing desire after fertility-impairing treatment

The aim of our study was to evaluate the feasibility and efficiency of delayed ovarian stimulation and metaphase II oocyte banking for fertility preservation after fertility-impairing treatment regardless of the initial disease. We conducted a cohort study based on population of women < 40 years of age with diminished ovarian reserve caused by fertility-impairing treatment (n = 129). Three groups of women were compared according to the type of initial disease: hematological malignancies, solid tumors, and benign diseases. The primary endpoint was the number of metaphase II oocytes collected per woman. We studied the cumulative live-birth rate per cycle with fertilized metaphase II oocyte, for women who wanted to conceive. We studied 245 delayed controlled ovarian stimulation cycles in 129 women: 201 for fertility preservation and 44 for in vitro fertilization and fresh embryo transfers. The number of metaphase II oocytes collected per woman after banking was similar in the three groups, with a mean of 10.7 ± 4.6, 12.3 ± 9.1, and 10.1 ± 7.6 metaphase II oocytes (p = 0.46), respectively. In the subgroup of women who wanted to conceive, the cumulative live birth rate per woman was 38%, with 8 live births for these 21 women. After fertility-impairing treatment, practitioners should discuss a fertility preservation procedure for banking metaphase II oocytes.