Effective protection: the embryonic development and clinical outcomes of emergency vitrification of 1246 oocytes and Day 0-Day 5 embryos in a natural disaster.

STUDY QUESTION: Can emergency vitrification protect embryos and oocytes during natural disasters or other events that prevent normal practice to achieve satisfactory embryonic development and clinical outcomes at a later time? SUMMARY ANSWER: Emergency vitrification of oocytes and Day 0-Day 5 (D0-D5) embryos during disasters is a safe and effective protective measure. WHAT IS KNOWN ALREADY: When some destructive events such as floods, earthquakes, tsunamis, and other accidents occur, emergency vitrification in embryo laboratories to protect human embryos, oocytes, and sperm is one of the important measures of an IVF emergency plan. However, there are few detailed reports on emergency vitrification in a state of disaster, especially about oocytes and D0 zygotes. Therefore, the effectiveness and safety of emergency vitrification of oocytes and D0-D5 embryos in disaster states are still unclear. STUDY DESIGN, SIZE, DURATION: A retrospective study was made in the Reproductive Medicine Center of the First Affiliated Hospital of Zhengzhou University from January 2018 to November 2022. The record rainstorms in Zhengzhou, China, caused severe flooding, traffic disruptions, and power outages. From 17:30, 20 July 2021 to 17:30, 21 July 2021, 1246 oocytes and D0-D5 embryos of 155 patients were vitrified whilst the laboratory had only an emergency power supply. PARTICIPANTS/MATERIALS, SETTING, METHODS: As of 21 December 2021, 1149 emergency vitrified oocytes and D0-D5 embryos of 124 patients underwent frozen-thawed embryo transfer (FET). They were divided into the following four groups according to the days of embryo culture in vitro: oocyte group, Day 0-Day 1 (D0-D1) group, Day 2-Day 3 (D2-D3) group, and Day 4-Day 5 (D4-D5) group. Control groups for each were selected from fresh cycle patients who underwent IVF/ICSI from January 2018 to October 2021. Control and emergency vitrification patients were matched on criteria that included age, fertilization method, days of embryonic development, and number and grade of transferred embryos. A total of 493 control patients were randomly selected from the eligible patients and matched with the emergency vitrification groups in a ratio of 4:1. The results of assisted reproduction and follow-up of pregnancy were analyzed. The embryonic development, clinical outcomes, and birth outcomes in each group were statistically analyzed. MAIN RESULTS AND THE ROLE OF CHANCE: A significant difference was observed in fertilization rate (81% versus 72%, P = 0.022) between the oocyte group and the control group. Significant differences were also observed in the monozygotic twin pregnancy rate (10% versus 0%, P = 0.038) and ectopic pregnancy rate (5% versus 0%, P = 0.039) between the D0-D1 group and the control group. No significant differences (P > 0.05) were observed between vitrified oocytes/D0-D1 embryos/D2-D3 embryos and the control group on the number of high-quality embryos (3.17 ± 3.00 versus 3.84 ± 3.01, P = 0.346; 5.04 ± 3.66 versus 4.56 ± 2.87, P = 0.346; 4.85 ± 5.36 versus 5.04 ± 4.64, P = 0.839), the number of usable blastocysts (1.22 ± 1.78 versus 1.21 ± 2.03, P = 0.981; 2.16 ± 2.26 versus 1.55 ± 2.08, P = 0.090; 2.82 ± 3.23 versus 2.58 ± 3.32, P = 0.706), clinical pregnancy rate (56% versus 57%, P = 0.915; 55% versus 55%, P = 1.000; 40% versus 50%, P = 0.488), miscarriage rate (30% versus 15%, P = 0.496; 5% versus 11%, P = 0.678; 17% versus 20%, P = 1.000), and live birth rate (39% versus 49%, P = 0.460; 53% versus 50%, P = 0.772; 33% versus 40%, P = 0.635). No significant differences (P > 0.05) were observed between the D4-D5 group and the control group on clinical pregnancy rate (40% versus 55%, P = 0.645), miscarriage rate (0% versus 18%, P = 1.000), and live birth rate (40% versus 45%, P = 1.000). LIMITATIONS, REASONS FOR CAUTION: The retrospective study design is a limitation. The timing and extent of natural disasters are unpredictable, so the sample size of vitrified oocytes, zygotes, and embryos is beyond experimental control. WIDER IMPLICATIONS OF THE FINDINGS: This study is the first study analyzing embryonic development, clinical outcomes, and birth outcomes of large samples of oocytes, D0 zygotes, and D1-D5 embryos after emergency vitrification under the disaster conditions. The results show that emergency vitrification is a safe and effective protective measure applicable to oocytes and D0-D5 embryos. The embryology laboratories need to be equipped with an emergency uninterrupted power supply capable of delivering for 6-8 h at full load. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Natural Science Foundation of China (grant 81871206). The authors declare that they have no conflicts of interest. All authors have completed the ICMJE Disclosure form. TRIAL REGISTRATION NUMBER: N/A.

The growth and development conditions in mouse offspring derived from ovarian tissue cryopreservation and orthotopic transplantation.

PURPOSE: To investigate the potential development or metabolic risk in offspring derived from mice with transplanted frozen-thawed ovarian tissue. METHODS: Mice ovaries were intervened by vitrification (group V) and slow-freezing (group S) cryopreservation and orthotopic transplantation. Orthotopic transplantation of fresh ovarian (group F) and natural mating (group C) served as control groups. The fertility restoration and health conditions of generations were assessed by offspring counts, anti-fatigue and motor ability, and organ morphology. The methylation rate and expression level of imprinted genes (IGF2R, H19, SNRPN, and PLAGL1) were used to predict the potential risk of development in transplanted generations. RESULTS: Both the percentage of normal morphological follicles in different developmental periods and the litter size of receipt mice were comparable in all three transplanted groups. There was no significant difference in offspring mice's birth defects, body weight gain, anti-fatigue ability, or exercise capacity among the four groups. The methylation rate of IGF2R, H19, and PLAGL1 showed a significant variation in cryopreservation groups as compared with control groups, as well as a difference in gene expression. The SNRPN appeared to be stable in methylation status. There were no differences in mRNA expression in all groups. CONCLUSIONS: The different ovarian tissue cryopreservation methods did not influence either maternal fertility function or offspring growth. However, these technologies could affect the methylation rate and expression level of some development-related imprinting genes in the offspring, which may lead to some indeterminacy risk.

The impact of endometrial thickness change after progesterone administration on pregnancy outcome in patients transferred with single frozen-thawed blastocyst.

BACKGROUND: The aim of this study was to explore the impact of endometrial thickness change after progesterone administration on pregnancy outcome in patients transferred with single frozen-thawed blastocyst. METHODS: This observational cohort study included a total of 3091 patients undergoing their first frozen-thawed embryo transfer (FET) cycles between April 2015 to March 2019. Endometrial thickness was measured by trans-vaginal ultrasound twice for each patient: on day of progesterone administration, and on day of embryo transfer. The change of endometrial thickness was recorded. RESULTS: Regardless of endometrial preparation protocol (estrogen-progesterone/natural cycle), female age, body mass index (BMI), and infertility diagnosis were comparable between patients with an increasing endometrium on day of embryo transfer and those without. However, clinical pregnancy rate increases with increasing ratio of endometrial thickness. Compared with patients with Non-increase endometrium, those with an increasing endometrium on day of embryo transfer resulted in significantly higher clinical pregnancy rate (56.21% vs 47.13%, P = 0.00 in estrogen-progesterone cycle; 55.15% vs 49.55%, P = 0.00 in natural cycle). CONCLUSIONS: In most patients, endometrial thickness on day of embryo transfer (after progesterone administration) increased or kept being stable compared with that on day of progesterone administration. An increased endometrium after progesterone administration was associated with better pregnancy outcome.

bFGF and VEGF improve the quality of vitrified-thawed human ovarian tissues after xenotransplantation to SCID mice.

PURPOSE: The aim of this research is to study whether basic fibroblast growth factor (bFGF) alone or in combination with vascular endothelial growth factor (VEGF) could improve the quality of vitrified-thawed human ovarian tissue xenotransplanted to severe combined immune deficiency (SCID) mice. METHODS: After collection and cryopreservation, thawed human ovarian tissue were cultured in vitro for 2 days and then xenografted to severe combined immune deficiency (SCID) mice for 7 days. The in vitro culture medium was separated into six groups, including (A) the blank control group, (B) the human recombinant bFGF (150 ng/ml) group, (C) the bFGF (150 ng/ml)+human recombinant VEGF (25 ng/ml) group, (D) bFGF (150 ng/ml)+VEGF (50 ng/ml) group, (E) bFGF (150 ng/ml)+ VEGF (75 ng/ml) group and (F) bFGF (150 ng/ml) + VEGF (100 ng/ml) group. In addition, eight pieces of thawed ovarian tissue were transplanted without in vitro culture, which serve as the fresh control group. The effect of transplantation was assessed by histological analysis, immunohistochemical staining for CD34, Ki-67, and AC-3 expression, and microvessel density (MVD). RESULTS: There was no significant difference between the fresh and blank control group. Compared to the blank control group, the number of follicles, MVD, and rate of Ki-67-positive cells increased significantly in groups B, C, D, E, and F, while apoptosis decreased significantly. Compared to the bFGF treatment group, no significant difference appeared in group C, D, E, and F. CONCLUSIONS: The administration of bFGF alone or in combination with VEGF improved the quality of postgraft human ovarian tissue, though VEGF, regardless of different concentrations, did not influence effect of bFGF.