Oocytes In Assisted Reproduction Research Articles

P-403 Oocyte usage and disposition outcomes following oocyte cryopreservation

Abstract Study question What is the fate of cryopreserved oocytes? Summary answer Very few people return to use their cryopreserved oocytes in assisted reproduction and while some surplus oocytes are donated for reproduction, the majority are discarded. What is known already The number of oocyte cryopreservation cycles performed around the world dramatically outpaces the number of people who return to use their oocytes in assisted reproduction. This imbalance is leading to the rapid accumulation of oocytes in cryostorage. Previous studies have reported that many people intend to donate their surplus cryopreserved oocytes, and some commentators suggest that this may help relieve donor shortages. However, there have been no reports to date about what actually happens to surplus oocytes following oocyte cryopreservation. Study design, size, duration A retrospective cohort study was performed, analysing the outcomes for cryopreserved oocytes from 2012 - 2022. Participants/materials, setting, methods Data were collected from seven IVF clinics, located in Victoria, Australia. De-identified data were aggregated on the outcomes following oocyte cryopreservation, including duration of cryostorage, assisted reproduction involving thawed oocytes, and disposition outcomes of surplus oocytes. Main results and the role of chance Across the study period, the number of patients with oocytes in storage grew rapidly from 144 in 2012 to 2015 in 2022. Regarding the current status of oocytes in storage, in 2022, 73% of patients had had their oocytes in storage for <5 years; 25% for 5 - 10 years, and 2% for ≥10 years. The majority of oocyte thaw cycles (600/645) involved oocytes frozen for <5 years; of which 47% were frozen for <6 months. Overall, the live birth rate from the total number of oocyte thaw cycles initiated was 12% (78/645), however, this varied depending on the reason oocytes were frozen. In comparison to the number of patients still with oocytes in storage, very few patients relinquished surplus oocytes across the study period (2015 vs 151, respectively). Of the 128 patients whose surplus oocytes were discarded, 32% had had their oocytes stored for <5 years; 32% for 5-10 years, and 36% for >10 years. Among patients who elected to donate their surplus oocytes (n = 23), all but four patients made this decision having had their oocytes in storage for <5 years. Although a legal option in Australia, no oocytes were donated to research over the period analysed. Limitations, reasons for caution Data were collected from one fertility group based in one state of Australia, thus it may not be representative of wider trends seen across other clinics or states/territories. Further, specific state laws govern the management, storage, and use of surplus oocytes, which may influence the reported disposition outcomes. Wider implications of the findings Our findings suggest that cryopreserved oocytes are rarely used or donated, rather they are left in storage, often for long durations. To relieve some of the pressure this may create on cryostorage facilities, more attention is needed to better understand the experience of oocyte disposition and the barriers to donation. Trial registration number not applicable

Donor oocyte cycle characteristics and outcomes: factors potentially linked with successful endings.

The use of donor oocytes in assisted reproduction has seen a significant rise worldwide in the last two decades. Postponement of motherhood and premature ovarian insufficiency are the main reasons for the increase in the number of in vitro fertilization cycles with donor oocytes. The present study aims to characterize donor oocyte cycles to analyze factors that may have an effect on live births and clinical pregnancy outcomes. Data were obtained from a single Assisted Reproduction Center in southern Brazil. Recipient demographics (n=148 patients) and cycle characteristics (n=213 cycles; 50 patients did more than one IVF attempt) were analyzed. Statistical analysis was performed using chi-squared and t-test as appropriate. On average, recipients that reached gestation were significantly younger than the ones that did not. We also observed a significant positive effect of constant dose estrogen therapy on pregnancies. Patient age and response to estradiol therapy are important factors in the attainment of the best possible outcomes in cycles with donor oocytes.

Applications of Melatonin in Female Reproduction in the Context of Oxidative Stress.

Oxidative stress has been recognized as one of the causal mediators of female infertility by affecting the oocyte quality and early embryo development. Improving oxidative stress is essential for reproductive health. Melatonin, a self-secreted antioxidant, has a wide range of effects by improving mitochondrial function and reducing the damage of reactive oxygen species (ROS). This minireview illustrates the applications of melatonin in reproduction from four aspects: physiological ovarian aging, vitrification freezing, in vitro maturation (IVM), and oxidative stress homeostasis imbalance associated with polycystic ovary syndrome (PCOS), emphasising the role of melatonin in improving the quality of oocytes in assisted reproduction and other adverse conditions.

Severe ovarian hyperstimulation syndrome with GnRH agonist trigger during the COVID pandemic: lessons learned from an unusual case

Background: Injectable gonadotropins stimulate multi-follicular recruitment and allows retrieval of multiple oocytes for assisted reproduction. The widespread utilization of gonadotropin releasing hormone agonist (GnRHa) to induce oocyte maturation for oocyte retrieval has nearly eliminated the risk of severe ovarian hyperstimulation syndrome (OHSS), and only a few cases have been reported in the literature. The rarity of severe OHSS may lead to the mistaken conclusion that gonadotropin stimulation can be safely administered with limited monitoring, even in high-risk patients. We present an unusual case of a woman with limited monitoring due to the COVID pandemic who developed severe OHSS before GnRH agonist trigger and oocyte. Case Presentation: A 29-year-old nulliparous woman with polycystic ovarian syndrome (PCOS) initiated ovarian stimulation for oocyte retrieval. She had a robust initial response, and developed worsening abdominal pain, bloating, nausea, vomiting, and decreased appetite before retrieval. GnRH agonist was given to “trigger ovulation and retrieval scheduled due to the low reported incidence of severe OHSS. Symptoms progressed, and on the morning of retrieval, ultrasound demonstrated bilaterally enlarged ovaries >10cm and 48 oocytes were retrieved for a planned cryo-all cycle. She was hospitalized on the day of retrieval for severe OHSS and had two large-volume paracenteses. She was stable and discharged home by day 5, and symptoms markedly improved with the onset of menses. She has an ongoing pregnancy from her first frozen embryo transfer. Conclusion: We add a rare case of severe OHSS with a GnRHa trigger and cryo-all protocol with the onset of symptoms before GnRH agonist administration. Although rare, severe OHSS may still occur with a GnRHa trigger, and caution is needed when an initial robust response is identified. Here we also provide an opportunity to review the important patient risk factors for the development of OHSS and measures to reduce the risk in excessive responders.

Signalling pathways and mechanistic cues highlighted by transcriptomic analysis of primordial, primary, and secondary ovarian follicles in domestic cat

In vitro growth (IVG) of dormant primordial ovarian follicles aims to produce mature competent oocytes for assisted reproduction. Success is dependent on optimal in vitro conditions complemented with an understanding of oocyte and ovarian follicle development in vivo. Complete IVG has not been achieved in any other mammalian species besides mice. Furthermore, ovarian folliculogenesis remains sparsely understood overall. Here, gene expression patterns were characterised by RNA-sequencing in primordial (PrF), primary (PF), and secondary (SF) ovarian follicles from Felis catus (domestic cat) ovaries. Two major transitions were investigated: PrF-PF and PF-SF. Transcriptional analysis revealed a higher proportion in gene expression changes during the PrF-PF transition. Key influencing factors during this transition included the interaction between the extracellular matrix (ECM) and matrix metalloproteinase (MMPs) along with nuclear components such as, histone HIST1H1T (H1.6). Conserved signalling factors and expression patterns previously described during mammalian ovarian folliculogenesis were observed. Species-specific features during domestic cat ovarian folliculogenesis were also found. The signalling pathway terms “PI3K-Akt”, “transforming growth factor-β receptor”, “ErbB”, and “HIF-1” from the functional annotation analysis were studied. Some results highlighted mechanistic cues potentially involved in PrF development in the domestic cat. Overall, this study provides an insight into regulatory factors and pathways during preantral ovarian folliculogenesis in domestic cat.

Risk disclosure and the recruitment of oocyte donors: are advertisers telling the full story?

This study analyzes 435 oocyte donor recruitment advertisements to assess whether entities recruiting donors of oocytes to be used for in vitro fertilization (IVF) procedures include a disclosure of risks associated with the donation process in their advertisements. Such disclosure is required by the self-regulatory guidelines of the American Society for Reproductive Medicine (ASRM) and by law in California for advertisements placed in the state. We find very low rates of risk disclosure across entity types and regulatory regimes, although risk disclosure is more common in advertisements placed by entities subject to ASRM's self-regulatory guidelines. Advertisements placed in California are more likely to include risk disclosure, but disclosure rates are still quite low. California-based entities advertising outside the state are more likely to include risk disclosure than non-California entities, suggesting that California's law may have a modest "halo effect." Our results suggest that there is a significant ethical and policy problem with the status quo in light of the known and unknown risks of oocyte donation and the importance of risk disclosure to informed consent in the context of oocyte donation.

Maduración in vitro de ovocitos: alternativa efectiva en reproducción asistida

Objetivos: Determinar la efectividad de la maduración in vitro (MIV) de ovocitos, como método de reproducción asistida. Diseño: Estudio descriptivo. Institución: Centro de Fertilidad y Ginecología del Sur (CFGS), Cusco, Perú. Participantes: Mujeres con diagnóstico de infertilidad. Intervenciones: Fueron ocho mujeres en las que se realizó MIV de ovocitos, seguido de ICSI, cultivo y vitrificación de embriones. Posteriormente, se preparó el endometrio de las pacientes y se realizó descongelación y transferencia de embriones. Principales medidas de resultados: Tasas de maduración de ovocitos, de fecundación, de embarazo clínico y de implantación. Resultados: La tasa de maduración de ovocitos fue 82,1%, de fecundación 95,7%, de embarazo clínico 62,5% y de implantación 29,4%. Conclusión: La MIV de ovocitos es una alternativa efectiva en reproducción asistida. Palabras clave: Maduración in vitro de ovocitos, fertilización in vitro, inyección intracitoplasmática de espermatozoides.

Human oocyte respiration-rate measurement – potential to improve oocyte and embryo selection?

Oocyte and embryo selection are not highly successful, with fewer than 10% of oocytes in assisted reproduction resulting in a delivery. Techniques for oocyte and embryo selection rely on highly subjective morphology assessment, with few true quantitative techniques available. One aspect of oocyte health that could be considered is the ability to produce ATP through respiration. Using a non-invasive technology, the respiration rates of individual human oocytes were recorded in an attempt to correlate respiration and oocyte health with probable subsequent development. Oocytes used were either immature or mature, non-fertilized oocytes from a clinical assisted reproduction programme. Differences in respiration rates between oocytes within a cohort and between cohorts of oocytes were recorded. The differences between cohorts reflected many of the currently known differences in oocyte health, related to age and FSH concentrations. However, within a cohort, differences between oocytes were observed, with some having high rates and others low. Oocytes with respiration rates of between 0.48 and 0.55 nl O 2/h were viable, with lower rates consistent with lack of continued in-vitro maturation or atresia. This technology may have a future in the clinical laboratory as a predictor of oocyte health and ability to develop into an embryo with greater potential of delivery.

Use of fetal oocytes in assisted reproduction

Some researchers have suggested that fetuses eventually might be used as a source for oocytes in oocyte donation programs (1, 2). One variant is to remove oocytes from the ovaries of aborted fetuses, mature them in vitro, and use them as donor oocytes for couples who need eggs as part of their IVF effort. A second variant is to remove ovaries from aborted fetuses and transplant them in women who lack ovarian function so the transplanted tissue eventually will contribute to the woman's normal reproductive cycle. Although at present the use of fetal oocytes for conception is hypothetical and speculative, its endorsement by some researchers and its critique by government-sponsored commissions make timely a discussion of its ethical dimensions (3, 4, 5).

Manipulation of the oocyte: possible damage to the spindle apparatus

Oocytes are structured, polarized cells. For high developmental potential, it is essential that the distribution of organelles and molecules, and the function of meiotic spindles remain intact during handling of oocytes in assisted reproduction. Spindles are dynamic cell organelles. Spindle formation depends on activity of motor proteins, energy supply and temperature. Disturbances in spindle function may predispose oocytes to aneuploidy or maturation arrest. Thus, perturbation of the cytoskeletal integrity of oocytes may critically influence the fate of the embryo. Recently, enhanced polarizing microscopy has been developed for non-invasive analysis of spindle morphology in living mammalian oocytes. Chemically induced dynamic alterations have been characterized in the spindle in individual mouse oocytes and it has been shown that spindle aberrations are predictive of risks for non-disjunction. Spindle imaging identified adverse, irreversible effects of handling in living human oocytes (for instance, the extreme susceptibility of human oocytes to cooling). Also, oocyte immaturity may be detected. Selection of metaphase II oocytes and an injection site for intracytoplasmic sperm injection (ICSI) that avoids spindle damage may increase the yield of euploid embryos. The detection of genetic, environmentally induced, or treatment-related defects in oocyte maturation by non-invasive spindle imaging can improve quality control and assist in the selection of morphologically normal oocytes for assisted reproduction.

The use of fetal oocytes in assisted reproduction

The use of fetal oocytes in assisted reproduction