N/A.

Study question Is systematic patient safety management training effective in improving awareness in safety confirmation and preventing errors in Embryo mix-up for embryologists? Summary answer From survey for 116 embryologists, they responded that they followed safety management instructions and regulations, and that they improved their safety work capability and awareness What is known already The cases of embryo mix-up known through the media include errors of sperm change during IUI, fertilization, Freeze-thawing, PGT, and Embryo transfer process, but there will be more due to statistical difficulties. Errors mostly occur because clinics do not have the right protocol. Currently, there aren’t any regulations or policies to track eggs, sperm, embryos or frozen embryos during ART. For this reason, infertile couples have to choose clinics with high pregnancy rates and safe clinics on their own to perform assisted reproductive techniques. Study design, size, duration This study was conducted through a survey of 116 embryologists who worked at five clinics of CHA fertility centers. The patient safety management system was created from the CHA fertility Center itself. From August 2021 to December 2022, safety confirmation training was conducted for 16 months. All embryologists were anonymously surveyed twice with 32 questions. The first survey was conducted in April 2022, and the second survey was in December 2022. Participants/materials, setting, methods The survey was conducted in 32 items with 10 categories. Interviewees’ made response for each item in five steps. Each item asked 1) Learning in the standard safety manual 2) Changes in safety awareness before and after training, 3) Compliance to the seven safety instruction (double checks) for each work part, 4) Level of difficulty in education, 5) Effects of education and 6) Suggestions for safety confirmation. Main results and the role of chance In the first survey, 61 out of 112 responded (54.5%) 60 out of 116 (51.7%) in the second. The answers were scored using a 5-point Likert scale (1 = strong disagree, 5 =  Strong agree). 1. The mean score for work satisfaction was 3.1 ± 0.8 out of 5 in the first survey and 3.1 ± 0.7 out of 5 in the second. Work satisfaction remained unchanged. 2. The perception of patient safety confirmation was 3.7/5 before training and 4.0/5 after training (p < 0.03) in the second which improved the perception of safety confirmation. 3. The safety confirmation ability through training was improved to 4.1/5(p < 0.01) after training compared to 3.8/5 in both the first and second surveys. 4. The necessity and importance of safety training were considered important in the first survey as it scored 3.6/5 and 4.5/5 (p < 0.001) in the second survey. 5. In the course of work, they responded that their safety management skills were improved (1st: 3.4/5, 2nd: 4.5/5(p < 0.05)) by the effects of training. As for CHA IVF lab, the embryologists were well aware of the guidelines (scoring 4.5/5 in the first and second survey) to know seven safety instructions (which are double check, outloud, RI witness, monitoring, document, information) should be followed well. Limitations, reasons for caution Embryo mix-up during ART procedures can be a major mistake to be avoided. The confirmed documentations can make errors any time. Establishing the safety protocol of the same process as ART procedure, the system, and education are important, but the most important is the safety management capability of the manager. Wider implications of the findings The safety management manual, the 7 CHA IVF laboratory patient safety instructions, online lecture training, field training, and inspection have raised awareness of the safety errors and the importance of double checking. Errors in safety can be prevented through systematic system development and repeated safety training. Trial registration number non-clinical trials

Study question Does embryo compaction positively correlate with blastocyst development and further embryonic ploidy status? Summary answer Fully compacted embryos develop into good-quality blastocysts, have shorter developmental times, and are related to ploidy status. What is known already To succeed in assisted reproduction technique (ART), it is necessary to select embryos that have the highest potential. So, numerous studies make an effort to establish parameters for selecting embryos. A Time-lapse system (TLS) allows embryologists to understand dynamic embryo change through continuous monitoring. In development, embryos undergo dynamic functional changes during compaction, which play a crucial role in blastocyst formation. It is also known that embryonic genome activation can be seen with compaction. Incomplete compaction leads to blastocyst developmental failure. Nevertheless, the details about the compaction of human embryos have not been paid sufficient attention, so still rarely known. Study design, size, duration This was a retrospective cohort study including couples that underwent an IVF cycle at the CHA Fertility Center, Gangnam, between January 2019 to October 2022. A total of 371 reached the blastocyst from 113 patients cultured in the TLS were analyzed. Among these, 94 blastocysts were analyzed by preimplantation genetic testing for aneuploidy (PGT-A). Statistical analysis was performed by prism9 using a t-test and chi-square test. P values <0.05 were regarded as statistically significant. Participants/materials, setting, methods Embryos were classified into two categories by compaction pattern: fully compacted (Group1, N = 194) and partially compacted (Group2, N = 177). Blastocyst quality was determined by morphology and divided into three groups (Good, Average, and Poor). The developmental time ranging from morula to blastocyst was annotated based on the embryo scope image. The surface of the blastocyst was measured every hour starting at blastocyst formation (tB) by using the ellipse tool of the Embryo Viewer software. Main results and the role of chance Good and average quality blastocysts are significantly higher in Group 1 than in Group 2 (21.6% vs. 3.4%, p < 0.01; 47.9% vs. 26.6%, p < 0.01, respectively). In contrast, poor-quality blastocysts are lower in Group 1 than in Group 2 (30.4% vs. 70.1%, p < 0.01). The beginning and completion of compaction, and blastocyst formation times of embryos from Group 1 were significantly shorter than those of embryos that Group 2(78.6h vs. 82.4, p < 0.01; 87.0h vs. 92.2h, p < 0.01; 100.2h vs. 103.7, p < 0.01, respectively). Also, there is a significant difference in longitudinal surface area at 3, 6, and 12h from the time of tB between the two groups. Consequently, the average expansion rate in Group 1 was significantly faster than in Group 2 (653.6 μm2/hour vs. 499.2μm2/hour, p < 0.05). According to the result of PGT-A, Group 1 had statistically significantly higher euploid and lower aneuploidy rates compared to Group 2 (47.2% vs. 36.2%, p < 0.001; 52.8% vs. 63.8%, p < 0.001, respectively). However, in the PGT-A group, there was no significant difference in developmental time between the two groups, regardless of fully or partial compaction. Meanwhile, the average expansion rate in euploidy blastocyst was significantly faster than in aneuploidy blastocyst (747.8 μm2/hour vs. 564.3 μm2/hour, p < 0.05). Limitations, reasons for caution The main limitation is the single-center retrospective approach. Therefore future prospective research is needed to verify and extend our findings. Another one, in the PGT-A there was no difference in developmental time regardless of fully or partially compaction. The reason is that we selected blastocysts of sufficient quality for biopsy. Wider implications of the findings Using the TLS, we have observed the dynamics of compaction in detail. We found a positive relationship between compaction and blastocyst quality and its association with embryo ploidy. The assessment of compaction is a significant parameter for predicting competent embryos and should be given priority when selecting blastocysts. Trial registration number Not applicable