What is the maximal timeframe between sperm acquisition to sperm cryopreservation, in different "culture" conditions?

OBJECTIVE: Most of the literature about postmortem sperm retrieval (PMSR) deals with the controversies surrounding ethical and legal aspects, while the optimal time interval between the death and viable sperm acquisition is indefinite. In an attempt to aid fertility specialists, while counseling whether to pursue and adopt PMSR, we aim to explore the maximal time frame from ejaculated sperm acquisition to sperm cryopreservation in different "culture" conditions, observations that might be extrapolated to PMSR requests. PATIENTS AND METHODS: Five healthy men with normal semen analysis were enrolled. The sperm specimen from each man was diluted to 6.5 mL. After extracting 0.5 mL for cryopreservation, the remaining 6 mL were divided into three tubes: one was maintained in room temperature (23-25 °C), the second in an incubator (37 °C), and the third in a refrigerator (4 °C). Thereafter, every day, a 0.5 mL of each sample was extracted, examined, and cryopreserved. A week later, all the cryopreserved samples were thawed and tested for sperm motility and viability. RESULTS: While at room temperature, frozen/thawed sperm were still motile (6.5%) and viable (9.9%) up to 96 h; those maintained in the refrigerator, following freezing/thawing were immotile already at 48 h in culture, but still viable (6.0%) up to 72 h in culture. Those maintained in the incubator demonstrated the worse results with negligible motility (1.5%) and viability (3.7%) following freezing/thawing, already after 48 h in culture. CONCLUSIONS: The timeframe cut-off between ejaculated sperm acquisition and cryopreservation should be 72 h, unless sperm was maintained at room temperature, where it might be longer. It would be prudent to check for sperm vitality prior to freezing in cases where only immotile sperms are present.

Is There Any Association Between the Number of Oocytes Retrieved, Women Age, and Embryo Development?

While most studies focused on the association between the number of oocytes retrieved and LBR, there is lack of analysis highlighting the effect of the number of oocyte retrieved on top quality embryo (TQE) rate in different age groups. We aimed to study the correlations between the number and ratio of TQE, as assessed by morphology only, according to the number of oocytes retrieved, and to evaluate the impact of patients' age. This was a retrospective study that includes 1639 patients who underwent 2263 IVF cycles between 2016 and 2019. Patients were categorized into four groups according to the number of oocytes retrieved: 1-3, 4-9, 10-14, or > 15 oocytes (OPU groups A-D, respectively). Another classification was according to patient's age < 35, 35-40, and > 40 years. Morphologically, TQE (both cleavage stage and blastocyst) was defined as those eligible for transfer or vitrification. TQE was assessed both as a fraction of oocytes retrieved per patients (rate) and the average TQE per number oocytes retrieved category. For all age subgroups, a negative significant association was observed between the number of oocytes retrieved and TQE rate (56.1%, 43.6%, 35.9%, and 34.3% for groups A-D, respectively). The reduction was significant up to 14 oocytes retrieved and plateau thereafter. On the other hand, TQE rate was significantly increased as women age increased, from 36.1% TQE rate in young women (< 35 years) to 40.3% for 35-40 years to 42.5% in older patients (> 40 years). Finally, a linear regression revealed a drop in TQE rate of - 0.5% for every oocyte retrieved, while an increased in TQE rate of + 0.7%, as the women age increased by 1 year. While young women are able to recruit more oocyte, including medium/low quality, older women recruit less oocytes, with good quality, as demonstrated by their higher morphologically TQE rate relative to the number of oocyte retrieved.

Do human embryos have the ability of self-correction?

Human embryogenesis frequently coinciding with cell division mistakes contributing to pervasive embryonic aneuploidy/mosaicism. While embryo self-correction was elegantly demonstrated in mouse models, human studies are lacking. Here we are witness to human embryos ability to eliminate/expel abnormal blastomeres as cell debris/fragments. Each blastocyst and its corresponding debris were separated and underwent whole genome amplification. Seven of the 11 pairs of blastocysts and their corresponding cell debris/fragments revealed discordant results. Of the 9 euploid blastocysts, four showed euploid debris, while in the others, the debris were aneuploid. In the remaining pairs, the debris showed additional aneuploidy to those presented by their corresponding blastocyst. The observed ability of human embryos to self-correction doubts many invasive and non-invasive preimplantation testing for aneuploidy at the blastocyst stage, rendering high rate of false positive (discarding "good" embryos) by identifying the cell-free DNA originated from the expelled cell debris, as aneuploidy/mosaic blastocyst.

Timing day-3 vitrification for PGT-M embryos: pre- or post-blastomere biopsy?

PURPOSE: To assess the efficacy and clinical outcomes of preimplantation genetic testing for monogenic diseases (PGT-M), following blastomere biopsy prior or following vitrification. METHODS: A cohort-historical study of all consecutive patients admitted to IVF in a large tertiary center for PGT-M and PCR cycle from September 2016 to March 2020. Patients were divided into 4 groups: Group A1 consisted of patients undergoing day-3 embryos biopsy followed by a fresh transfer of unaffected embryos. Group A2 consisted of Group A1 patients that their surplus unaffected embryos were vitrified, thawed, and transferred in a subsequent FET cycle. Group B1 consisted of patients that their day-3 embryos were vitrified intact (without biopsy) for a subsequent FET cycle. Later embryos were thawed and underwent blastomere biopsies, and the unaffected embryos were transferred, while the surplus unaffected embryos were re-vitrified for a subsequent FET cycle. Group B2 consisted of Group B1 patients that their surplus unaffected embryos were re-vitrified, thawed, and transferred in a subsequent FET cycle. The laboratory data and clinical results were collected and compared between groups. RESULTS: A total of 368 patients underwent 529 PGT-M cycles in our center: 347 with day-3 embryos biopsied before undergoing vitrification (Group A1) and 182 following vitrification and thawing (Group B1). There were no between group differences in embryo survival rate post-thawing, nor the ongoing implantation and pregnancy rates. CONCLUSION: In PGT-M cycles, the timing of embryos vitrification, whether prior or following blastomere biopsy, has no detrimental effect on post-thawing embryo survival rate, nor their potential ongoing implantation and pregnancy rates.

Can we predict oocyte maturation prior to denudation for intracytoplasmic sperm injection?

Intracytoplasmic sperm injection (ICSI) was introduced in 1992 as a method to treat couples with severe male infertility. However, in the last two decades, the use of ICSI has increased substantially even among patients without male factor infertility. In ICSI the oocytes are scrutinized for maturity upon insemination and the immature oocytes are discarded. The aim of the present study was to assess the ability of an experienced embryologist to identify the maturity of the oocytes prior to their denudation.In the present prospective observational study, four experienced embryologists examined the oocytes prior to their denudation and decided whether the oocytes were mature or immature. Later, the oocytes were denudated and the embryologist again examined the oocytes to confirm their prior assumptions.483 oocytes were examined by four embryologists. Three hundred and fifty one of the oocytes were mature (72.7%) and 132 were immature (27.3%). The embryologists were able to correctly identify oocytes maturation status in 85.3% of cases. The embryologists were able to correctly identify 90% of the mature oocytes and 72.7% of the immature oocytes. When they assumed that the oocytes were mature they were correct in 89.% of the cases, while only 74.6% of their prediction that the oocytes were immature were true. To conclude, the embryologists are able to identify the oocytes maturation status before denudation at the majority of the cases. Whenever the oocytes are suspected to be immature, further consideration should be made whether to proceed to ICSI or not.