Study question Can the approach to, and terminology for, time-lapse monitoring of preimplantation embryo development be uniformly defined in order to improve the utilization and impact of this novel technology? Summary answer The adoption of the proposed guidelines for defining annotation practice and universal nomenclature would help unify time-lapse monitoring practice, allow validation of published embryo selection algorithms and facilitate progress in this field. What is known already An increasing quantity of publications and communications relating to time-lapse imaging of in vitro embryo development have demonstrated the added clinical value of morphokinetic data for embryo selection. Several articles have identified similar embryo selection or de-selection variables but have termed them differently. An evidence-based consensus document exists for static embryo grading and selection but, to date, no such reference document is available for time-lapse methodology or dynamic embryo grading and selection. Study design, size and duration A series of meetings were held between September 2011 and May 2014 involving time-lapse users from seven different European centres. The group reached consensus on commonly identified and novel time-lapse variables. Participants/materials, setting, methods Definitions, calculated variables and additional annotations for the dynamic monitoring of human preimplantation development were all documented. Main results and the role of chance Guidelines are proposed for a standard methodology and terminology for the of use time-lapse monitoring of preimplantation embryo development. Limitations, reasons for caution The time-lapse variables considered by this group may not be exhaustive. This is a relatively new clinical technology and it is likely that new variables will be introduced in time, requiring revised guidelines. A different group of users from those participating in this process may have yielded subtly different terms or definitions for some of the morphokinetic variables discussed. Due to the technical processes involved in time-lapse monitoring, and acquisition of images at varied intervals through limited focal planes, this technology does not currently allow continuous monitoring such that the entire process of preimplantation embryo development may be visualized. Wider implications This is the first time that a group of experienced time-lapse users has systematically evaluated current evidence and theoretical aspects of morphokinetic monitoring to propose guidelines for a standard methodology and terminology of its use and study, and its clinical application in IVF. The adoption of a more uniform approach to the terminology and definitions of morphokinetic variables within this developing field of clinical embryology would allow practitioners to benefit from improved interpretation of data and the sharing of best practice and experience, which could impact positively and more swiftly on patient treatment outcome. Study funding/competing interests There was no specific funding for the preparation of these proposed guidelines. Meetings were held opportunistically during scientific conferences and using online communication tools. H.N.C. is a scientific consultant for ESCO, supplier of Miri TL. I.E.A. is a minor shareholder in Unisense Fertilitech, supplier of the EmbryoScope. Full disclosures of all participants are presented herein. The remaining authors have no conflict of interest.

/pdf/proposed-guidelines-on-the-nomenclature-and-annotation-of-mnfls89md2.pdf

Proposed guidelines on the nomenclature and annotation of dynamic human embryo monitoring by a time-lapse user group

STUDY QUESTION
Can a deep learning model predict the probability of pregnancy with fetal heart (FH) from time-lapse videos?

/pdf/deep-learning-as-a-predictive-tool-for-fetal-heart-pregnancy-4lfpu3yke3.pdf

Deep learning as a predictive tool for fetal heart pregnancy following time-lapse incubation and blastocyst transfer

STUDY QUESTION Can we use morphokinetic markers to select the embryos most likely to implant and are the results likely to be consistent across different clinics? SUMMARY ANSWER Yes, morphokinetic markers can be used to select the embryos most likely to implant and the results were similar in different IVF clinics that share methods and organization to some extent. WHAT IS KNOWN ALREADY With the introduction of time-lapse technology several authors have proposed the use of kinetic markers to improve embryo selection. The majority of these markers can be detected as early as Day 2 of development. Morphology remains the gold standard but kinetic markers have been proven as excellent tools to complement our decisions. Nevertheless, the majority of time-lapse studies are based on small data sets deriving from one single clinic. STUDY DESIGN, SIZE, DURATION Retrospective multicentric study of 1664 cycles of which 799 were used to develop an algorithm (Phase 1 of the study) and 865 to test its predictive power (Phase 2 of the study). PARTICIPANTS/MATERIALS, SETTING, METHODS University-affiliated infertility centres patients undergoing first or second ICSI cycle using their own or donated oocytes. Embryo development was analysed with a time-lapse imaging system. Variables studied included the timing to two cells (t2), three cells (t3), four cells (t4) and five cells (t5) as well as the length of the second cell cycle (cc2 = t3 - t2) and the synchrony in the division from two to four cells (s2 = t4 - t3). Implantation (IR) and clinical pregnancy (CPR) rates were also analysed. MAIN RESULTS AND THE ROLE OF CHANCE During Phase 1 of the study we identified three variables most closely related to implantation: t3 (34-40 h), followed by cc2 (9-12 h) and t5 (45-55 h). Based on these results we elaborated an algorithm that classified embryos from A to D according to implantation potential. During Phase 2 of the study the algorithm was validated in a different group of patients that included 865 cycles and 1620 embryos transferred. In this phase of the study, embryos were categorized based on the algorithm and significant differences in IR were observed between the different categories ('A' 32%, 'B' 28%, 'C' 26%, 'D' 20% and 'E' 17%, P < 0.001). In addition we identified three quality criteria: direct cleavage from one to three cells, uneven blastomere size in second cell cycle and multinucleation in third cell cycle. LIMITATIONS, REASONS FOR CAUTION The retrospective nature of the study limits its potential value, although the use of one database to generate the algorithm (embryos from this database were not selected by any morphokinetic criteria) and one database to validate it reinforces our conclusions. WIDER IMPLICATIONS OF THE FINDINGS The elaboration of an algorithm based on a larger database derived from different (albeit related) clinics raises the possibility that such algorithms could be applied in different clinical settings.

/pdf/the-use-of-morphokinetics-as-a-predictor-of-implantation-a-48b17n8c83.pdf

The use of morphokinetics as a predictor of implantation: a multicentric study to define and validate an algorithm for embryo selection

The human ovary orchestrates sex hormone production and undergoes monthly structural changes to release mature oocytes. The outer lining of the ovary (cortex) has a key role in defining fertility in women as it harbors the ovarian reserve. It has been postulated that putative oogonial stem cells exist in the ovarian cortex and that these can be captured by DDX4 antibody isolation. Here, we report single-cell transcriptomes and cell surface antigen profiles of over 24,000 cells from high quality ovarian cortex samples from 21 patients. Our data identify transcriptional profiles of six main cell types; oocytes, granulosa cells, immune cells, endothelial cells, perivascular cells, and stromal cells. Cells captured by DDX4 antibody are perivascular cells, not oogonial stem cells. Our data do not support the existence of germline stem cells in adult human ovaries, thereby reinforcing the dogma of a limited ovarian reserve.

/pdf/single-cell-analysis-of-human-ovarian-cortex-identifies-13p8hfwkim.pdf

Single-cell analysis of human ovarian cortex identifies distinct cell populations but no oogonial stem cells

Importance In the US, approximately 12.7% of reproductive age women seek treatment for infertility each year. This review summarizes current evidence regarding diagnosis and treatment of infertility. Observations Infertility is defined as the failure to achieve pregnancy after 12 months of regular unprotected sexual intercourse. Approximately 85% of infertile couples have an identifiable cause. The most common causes of infertility are ovulatory dysfunction, male factor infertility, and tubal disease. The remaining 15% of infertile couples have “unexplained infertility.” Lifestyle and environmental factors, such as smoking and obesity, can adversely affect fertility. Ovulatory disorders account for approximately 25% of infertility diagnoses; 70% of women with anovulation have polycystic ovary syndrome. Infertility can also be a marker of an underlying chronic disease associated with infertility. Clomiphene citrate, aromatase inhibitors such as letrozole, and gonadotropins are used to induce ovulation or for ovarian stimulation during in vitro fertilization (IVF) cycles. Adverse effects of gonadotropins include multiple pregnancy (up to 36% of cycles, depending on specific therapy) and ovarian hyperstimulation syndrome (1%-5% of cycles), consisting of ascites, electrolyte imbalance, and hypercoagulability. For individuals presenting with anovulation, ovulation induction with timed intercourse is often the appropriate initial treatment choice. For couples with unexplained infertility, endometriosis, or mild male factor infertility, an initial 3 to 4 cycles of ovarian stimulation may be pursued; IVF should be considered if these approaches do not result in pregnancy. Because female fecundity declines with age, this factor should guide decision-making. Immediate IVF may be considered as a first-line treatment strategy in women older than 38 to 40 years. IVF is also indicated in cases of severe male factor infertility or untreated bilateral tubal factor. Conclusions and Relevance Approximately 1 in 8 women aged 15 to 49 years receive infertility services. Although success rates vary by age and diagnosis, accurate diagnosis and effective therapy along with shared decision-making can facilitate achievement of fertility goals in many couples treated for infertility.

https://jamanetwork.com/journals/jama/articlepdf/2781637/jama_carson_2021_rv_210009_1625172026.74764.pdf

Diagnosis and Management of Infertility: A Review.

Morphokinetic analysis and embryonic prediction for blastocyst formation through an integrated time-lapse system.

The morphology of fertilization events has been related to successful implantation by subjective criteria (pronuclei score, pronuclei symmetry and position). This work first described these events by time-lapse technology and then compared the timings of fertilization events (second polar body extrusion, first and second pronuclei appearance, abuttal and fading) in implanted versus nonimplanted embryos in a 2-year cohort retrospective study. A total of 1448 transferred embryos from 842 patients undergoing intracytoplasmic sperm injection with oocyte donation were monitored, 212 embryos from treatments where the number of gestational sacs matched the number of transferred embryos and 687 embryos from treatments no biochemical pregnancy was achieved. The timings at which second polar body extrusion (3.3-10.6 h), pronuclear fading (22.2-25.9 h) and length of S-phase (5.7-13.8 h) occurred were linked successfully to embryo implantation. The other parameters were apparently not related, as determined by image acquisition and time-lapse analysis.

https://www.rbmojournal.com/article/S1472-6483(13)00631-7/pdf

The human first cell cycle: impact on implantation

Mitochondria as a tool for oocyte rejuvenation.

Autologous mitochondrial transfer as a complementary technique to intracytoplasmic sperm injection to improve embryo quality in patients undergoing in vitro fertilization—a randomized pilot study

Research question How can laboratory and clinical outcomes of spontaneously, early maturing germinal-vesicle oocytes and sibling in-vivo-matured (metaphase II [MII]) oocytes be quantified and compared? Design A prospective, non-randomized intra-cohort study of oocytes from women aged 38 years or younger, with six or fewer MII oocytes and four or more germinal vesicles retrieved. No indication was identified for genetic tests or oocyte or embryo cryopreservation. The study was carried out at IVIRMA-Valencia. Early maturing germinal vesicles were selected for reproductive purposes. In vitro- and in-vivo MII oocytes were fertilized. After time-lapse culture, hatching blastocysts from germinal vesicles were biopsied for aneuploidy screening and vitrified. Laboratory and clinical outcomes were compared according to oocyte origin. Results Almost 70% of germinal vesicles had matured early and spontaneously, and had comparable in vitro-outcomes and morphokinetics to sibling in vivo-matured oocytes. Fifty per cent of biopsied blastocysts were euploid. Germinal-vesicle rescue increased the number of MII oocytes per cycle to 3.9, finally adding one extra-blastocyst per cycle. A live birth confirmed the feasibility of this approach. Further data, however, are needed to quantify its real contribution to standard intracytoplasmic sperm injection cycles. Nevertheless, 40% of patients obtained either an immediate advantage (reduction of cancellation rate) or long-term benefit (availability of extra blastocysts of attempts). Conclusions Germinal-vesicle rescue can be considered as a complementary approach when folliculometry (expected) and number of MII (observed) are unequal.

María José Escribá

Papers

Morphokinetic analysis and embryonic prediction for blastocyst formation through an integrated time-lapse system.

The human first cell cycle: impact on implantation

Mitochondria as a tool for oocyte rejuvenation.

Autologous mitochondrial transfer as a complementary technique to intracytoplasmic sperm injection to improve embryo quality in patients undergoing in vitro fertilization—a randomized pilot study

Do immature and mature sibling oocytes recovered from stimulated cycles have the same reproductive potential