• Clinical and Experimental Reproductive Medicine
• /
• 제51권1호
• /
• pp.85-90
• /
• 2024

Objective: The purpose of this study was to compare fresh and frozen-thawed euploid blastocyst transfer protocols following preimplantation genetic screening (PGS) in cases of advanced maternal age. Methods: A total of 330 patients were examined retrospectively. PGS was performed on the embryos of 146 patients for whom fresh transfers were chosen. In contrast, frozen-thawed euploid single embryo transfer (ET) was selected after PGS for 184 patients, and their embryos were vitrified. The percentage of euploid embryos and rates of implantation, pregnancy, and pregnancy continuity, as well as clinical and biochemical abortion rates, were compared. Results: The numbers of retrieved oocytes, metaphase II oocytes, and fertilized ova were greater in the frozen-thawed group. The percentages of euploid embryos were comparable between the fresh and frozen-thawed groups (32% vs. 34.8%, respectively). The rates of implantation (46.6%vs. 62.5%), pregnancy (50% vs. 66.8%), ongoing pregnancy (38.4% vs. 53.8%), and live birth percentage (37.0% vs. 53.8%) were significantly higher in the frozen-thawed group. However, no significant differences were found in the clinical and biochemical abortion rates. Conclusion: The use of frozen-thawed single euploid ET is associated with increased implantation and pregnancy rates compared to fresh single euploid ET with PGS.

• Clinical and Experimental Reproductive Medicine
• /
• 제43권2호
• /
• pp.106-111
• /
• 2016

Objective: To study the clinical outcomes of single frozen-thawed blastocyst transfer cycles according to the hatching status of frozen-thawed blastocysts. Methods: Frozen-thawed blastocysts were divided into three groups according to their hatching status as follows: less-than-expanded blastocyst (${\leq}EdB$), hatching blastocyst (HgB), and hatched blastocyst (HdB). The female age and infertility factors of each group were evaluated. The quality of the single frozen-thawed blastocyst was also graded as grade A, tightly packed inner cell mass (ICM) and many cells organized in the trophectoderm epithelium (TE); grade B, several and loose ICM and TE; and grade C, very few ICM and a few cells in the TE. The clinical pregnancy and implantation rate were compared between each group. The data were analyzed by either t-test or chi-square analysis. Results: There were no statistically significant differences in average female ages, infertility factors, or the distribution of blastocyst grades A, B, and C in each group. There was no significant difference in the clinical pregnancy and implantation rate of each group according to their blastocyst grade. However, there was a significant difference in the clinical pregnancy and implantation rate between each group. In the HdB group, the clinical pregnancy and implantation rate were similar regardless of the blastocyst quality. Conclusion: There was an effect on the clinical outcomes depending on whether the blastocyst hatched during single frozen-thawed blastocyst transfer. When performing single frozen-thawed blastocyst transfer, the hatching status of the frozen-thawed blastocyst may be a more important parameter for clinical outcomes than the quality of the frozen-thawed blastocyst.

• 한국수정란이식학회지
• /
• 제6권2호
• /
• pp.47-51
• /
• 1991

This study investigated full-term development potential of ultrarap idly frozen and thawed mouse 2-cell embryos. Mouse 2-cell embryos, dehydrated by exposure to freezing medium, were directly immersed into liquid nitrogen and thawed in 37$^{\circ}C$ water. The embryos that were frozen and thawed were cultured in uitro and transferred to foster mothers to examine there developmental potential. As a result, the frozen-thawed 2-cell embryos developed to blastocysts in vitro as a similar rate as control 2-cell embryos did(in vitro 2-cell, 86.4%; in vivo 2-cell, 90.9%; solution control, 89.9%; control, 89.7%). Normal live young were obtained from transfer of frozen-thawed embryos to the oviduct and uterus of pseudopregnant recipients (3l.4~56.7%).

• 한국수정란이식학회지
• /
• 제11권2호
• /
• pp.137-144
• /
• 1996

The present study was carried out to obtain the pregnancy and delivery rate following transfer of fresh and frozen-thawed Korean native cattle(KNC) blastocysts(1~4 em-bryos / head) produced in vitro to Holstein recipients. The pregnancy rate of fresh and frozen-thawed KNC blastocysts produced in vitro was 50%(7 /14 heads) and 38.5%(5 /13 heads), respectively. The pregnancy rate of frozen-thawed KNC blastocysts produced in vitro frozen using 1.5M ethylene glycol and 1.4M glycerol for cryoprotectant was 33.3%(2 /6 heads) and 42.9 %(3 /7 heads), respectively. Seven calves including 2 sets of twin were born fiom 5 pregnant recipients receiving eleven fresh blastocysts. Three pregnant recipients were aborted among four pregnant recipients receiving twelve frozen-thawed blastocysts and one calf was born from the rest of one pregnant recipient.

• 한국수정란이식학회지
• /
• 제16권1호
• /
• pp.29-34
• /
• 2001

To investigate the effect of co-transfer of trophoblastic vesicle (TV) with frozen-thawed in vitro Produced (IVP) bovine embryo on pregnancy rate, IVP blastocysts were transferred to synchronized recipients. Elongated blastocysts were recovered at Day 13 to 15, and dissected more than 4 pieces to removed the embryonic disc. Throphoblastic fragments were cultured for 48 hours to make throphoblastic vesicles (TVs). TVs were cryopreserved in ethylene glycol or vitrification solution and frozen-thawed TVs were co-transferred to recipients with frozen-thawed IVP embryos. 1 The recovery rate of elongated blastocyst on Day 13 to 15 was 22.5% (18/80) and the size of recovered elongated blastocysts was 0.2∼5.0mm. 2. Eighteen elongated blastocysts were dissected into 88 pieces and 61.4% of those pieces were formed to TV (54/88) 3. The viability of frozen-thawed TV in ethylene glycol was higher than in vitrified solution (92.8% vs. 68.8%) 4. The pregnancy rate in co-transfer with frozen-thawed TV and IVP blastocyst was better than transfer only IVP blastocysts (50.0% vs. 23.1%).

• 한국수정란이식학회지
• /
• 제12권1호
• /
• pp.67-74
• /
• 1997

This study was carried out to increase the viability of bovine frozen4hawed in vitro produced (IVP) embryos and pregnancy rate by direct transfer method. Cumulus-oocyte complexes were aspirated from excised Hanwoo ovaries and matured in TGM 199 for 20~22 hours at 38.5$^{\circ}C$ in 2% $CO_2$ in air. Matured oocytes were fertilized with capacitated sperm for 6 hours and then co-cultured with cumulus cells for 9 days. 63% of the oocytes cultured was deaved and 29% out of them developed into blastocysts. Good or excellent grade of blastocysts on D 7 or 8 were frozen with 1.8M ethylene glycol as a cryoprotectant for direct transfer. Frozen embryos were thawed at 2$0^{\circ}C$ water for 10 sec following 4~5 second in air. For the survival assay of frozen4hawed lVP blastocysts, they were cultured in TCM 199 supplemented with 100$\mu$M $\beta$-mercaptoethanol and 20% FCS for 72 hours. The percentage of embryos developed to re-expanded or hatched after 72 hours culture was 95. 5 and 77.3%, respectively. When frozen-thawed Ivp embryos were transferred to 43 synchronized recipients by direct transfer method, eighteen recipients (41.8%) was pregnant. The highest pregnant was in naturafly synchronized recipients (71.4%), but induced estrus by using PRID(29.2%) and PGF$_2$$\alpha$(20.0%) was showed lower pregnancy rate. The pregnancy rate was higher in day 7 blastocysts(56.0%) than day 8 blastocysts(22.2%). (Key words: in vitro produced, blastocyst, frozen-thawed, direct transfer)

• Journal of Animal Science and Technology
• /
• 제65권4호
• /
• pp.779-791
• /
• 2023

This study aimed to assess the effects of embryonic developmental stage, quality grade, and fresh or frozen/thawed conditions on the pregnancy rate and sex ratio of live offspring in Hanwoo (Bos taurus coreanae) cows. The quality and developmental stage of in vivo-derived (IVD) transferred embryos were evaluated using the standard criteria of the International Embryo Technology Society. The recipient cows were synchronized using conventional (estradiol benzoate and progesterone) protocols before embryo transfer. Embryos were transferred to 297 cows, and pregnancy was monitored for 60-70 days after embryo transfer. The pregnancy rates of fresh and frozen/thawed embryos were 56.90% and 52.49%, respectively. Pregnancy rates varied according to embryo quality (56.18% for grade 1 vs. 36.67% for grade 2). Pregnancy rates also varied by developmental stage and cryopreservation (67.86% vs. 63.49% for stage 4-1, 64.00% vs. 54.72% for 5-1, and 50.00% vs. 47.83% for 6-1, in fresh embryos vs. frozen/thawed embryos, respectively). For stage 7-1, the pregnancy rates were 72.73% for fresh embryos and 20.00% for frozen/thawed embryos. In 66 fresh embryos, the sex ratio of live offspring was 5:5, whereas it was 4(female):6(male) for frozen/thawed embryos among the 95 frozen/thawed embryos. The miscarriage rate was approximately 3% higher for frozen/thawed embryos than for fresh embryos (18.1% for fresh vs. 21.1% for frozen). Seasonal fertility rates were 33.3% in spring, 55.67% in summer, 52.8% in autumn, 60.0% in winter. The following male-to-female ratios were observed in different seasons: 6.7:3.3 in spring, 4.0:6.0 in summer, 5.5:4.5 in autumn, and 3.3:6.7 in winter. The current data revealed no significant differences in pregnancy rates between fresh and frozen/thawed IVD embryos. However, there was a lower pregnancy rate with advanced-stage frozen/thawed embryos (stage 7-1). The current study provides comprehensive results for the better optimization of embryo transfer in Hanwoo cattle to obtain the desired fertility rate, pregnancy rate, and sex ratio of calves. These results provide important insights into the factors that influence the viability and success of IVD embryo transfer in Hanwoo cows and may have practical applications for improving breeding programs and reducing production costs.

• 한국수정란이식학회지
• /
• 제11권2호
• /
• pp.151-158
• /
• 1996

This study was carried out to investigate the effect of equilibration time, sucrose concentration and age of embryo on survival and developmental rates of bovine IVF expanding blastocysts frozen-thawed by direct transfer method. The bovine oocytes were collected from 2~5mm follicles, matured for 20~24hrs in 5% $CO_2$incubator and then fertilized with frozen-thawed semen. Expanding blastocysts at day 7, 8, 9, 10 and 11 after IVF were frozen in 1.8M ethylene glycol(EG). Survival and hatching rates of frozen-thawed IVF embryos were examined. The results were as follow ; Survival and hatching rate of TVF expanding blastocysts after 10, 20, 3Omin exposure in 1.8M EG were 100,0,90.9, 47.1, 85.0, 75.0 and 62.5% respectively. Survival rates of IVF expanding blastocysts frozen with 1.8M EG and various concentration(0, 0.25, 0.5, 1M) of sucrose were 73.3, 25. 0, 16.7, 9.1% respectively. Survival and hatching rates of IVF expanding blastocysts frozen-thawed according to age of embryo(Day 7, 8, 9,10, 11) were 86.1, 84.8, 79.3, 61.4, 51.3, 74.2, 76.9, 71.7, 63.0 and 65.0% respectively. In conclusion, the age of the embryo(Day 7, 8) is very important for the successful freezing of IVF bovine embryos and 1.8M ethylene glycol not containing sucrose may be effective cryoprotectant for direct transfer method.

• 한국수정란이식학회지
• /
• 제10권3호
• /
• pp.243-250
• /
• 1995

Frozen storage of the oocytes has been used in a few mammalian species including mouse, hamster, human and cattle. However, frozen4hawed oocvtes show different sperm penetration on the levels of the zona pellucida and the plasma memhrane when compared with fresh oocytes. To elucidate biological changes occurring during freezing and thawing, we examined the kinetics of sperm penetration into frozen-thawed hamster oocytes. Oocytes obtained from superovulated female golden hamsters were frozen-thawed in an autofreezer according to an established method. Fresh and frozen4hawed oocytes were fertilized in vitro with capacitated hamster spermatozoa after removing the zona pellucida. The oocytes were examined at 1, 2, 3 and 6 h postinsemination. Sperm penetration found to be 1 h delayed in frozen-thawed oocytes. Other parameters such as degree of polyspermy and decondensing sperm heads were not affected by freezing and thawing. The results suggest that freezing and thawing may cause changes in the egg membrane surface and subsequently which leads to delay in the sperm-egg fusion.

• 한국수정란이식학회지
• /
• 제12권1호
• /
• pp.75-90
• /
• 1997

This study was carried out to establish the techniques for producing the calves of genetically superior Korean Native cattle by transfer of frozen-thawed embryos. The effects of some factors related to embryo recovery following superovulation and pregnancy rate following transfer of frozen-thawed embryos were evaluated. Also calving state was investigated. The results obtained were as follows ; The mean number of total and transferrable embryos recovered per superovulated cow was 8.72 and 4.90, respectively, from a total of 72 superovulations using 34 donor cows. There were no significant differences in the number of total or transferrable embryos recovered per superovulated cow between products of follicle stimulating hormone (FSH), years, seasons, and collection numbers. The pregnancy rate was found 44.44% following transfer of frozen-thawed embryos of Korean Native cattle to a total of 180 recipient cows including 82 Angus, 27 Charolais, 62 Hereford and 9 Korean Native cows. The pregnancy rate was significantly (P<0.05) higher in the transfer of excellent (42.99) and good embryos (40.17%), compared with fair (5.90%) grade embryos. And the pregnancy rate was significantly (P<0.05) higher in the transfer of embryos of morula stage (43.86%) than blastocyst stage (15.51%). But there were no significant differences in pregnancy rates between natural and induced estrus estrus asynchrony of 1 days, breeds, and parities of recipient cows. The normal calving rate of 80 pregnant cows following transfer of frozen4hawed em-bryos was 87.5% and the other 10 pregnant cows showed abortion during the period from pregnancy diagnosis at 50~60 days to calving. The average gestation length of normally delivered recipients was 288.50 days and the average birth weight of 70 calves born was 24.22 kg. The gestation length was significantly (P<0.05) shorter in the recipients delivering female calves (286.70 days) than males (289.39 days). But there were no significant differences in gestation tength and birth weight of calves born between the recipient breeds.