2023년도 대한생식의학회 (KSRM) - 우수 포스터상 - Effect of thawing time in the morning or afternoon one day before frozen-thawed embryo transfer on pregnancy and miscarriage rates. (동결배아 이식을 위해 하루전 배아-해동시간(오전/오후)은 임신율에 영향을 주지 않는다)

Ho Jeong Son, Seok Gi Kim, Jun Sang Park, Min Ji Kim, Ga Won Kim, Gyeong Deok Heo, Hye Yoon Kim, Ji Yun Seong, Hye Kyung Noh, Kyeong Ho Lee
Mamapapa&Baby Ob/Gy clinic, Baby dream research center, Ulsan, Korea- South.

Objective

The objective of the study was to compare the clinical outcome of morning or afternoon thawing time of frozen-thawed embryos one day before thawing

Methods

This retrospective study was performed on, 2868 frozen-thawed embryo transfer cases performed from January 2018 to October 2022. Total 4338 embryos were divided into two groups according to thawing time (morning thaw, culture 24 hours vs. afternoon thaw, culture 16 hours). In addition, the pregnancy and miscarriage rate were compared in cleaved embryos FET and blastocysts FET. Frozen–thawed embryos were transferred at the cleavage stage (n=1582: morning thaw, 766; afternoon thaw, 816) or the blastocyst stage (n=1286: morning thaw, 666; afternoon thaw, 620). Based on following cases, the pregnancy and miscarriage rate were calculated respectively.

Results

There were no differences in patient’s age (morning thaw vs. afternoon thaw 37.0±4.3 vs.36.7±4.3), the mean number of transferred embryos (1.6±0.6 vs. 1.6±0.5) and endometrial thickness (10.1±2.3 vs. 10.0±2.2). The overall clinical pregnancy rates were 55.8% (799/1442) morning thaw and 55% (790/1436) afternoon thaw. In addition, the miscarriage rate was 9% (72/799) and 10.9% (86/790), respectively. Moreover, there are no significant difference in pregnancy rates morning thaw and afternoon thaw between the cleavage stage (50.2% vs. 48.4% p=0.49) and the blastocyst stage (62% vs. 63.6% p=0.6). The abortion rate also comparable regardless of thawing time in the cleavage stage (10.6% vs. 10.86% p=0.97) and the blastocyst stage (7.51% vs. 10.91% p=0.16).

Conclusion

No significant differences between two groups (morning thaw, culture 24 hours vs. afternoon thaw, culture 16 hours) in cleaved stage embryo and blastocyst vitrified-warmed cycles. Therefore, the thawing time of FETs does not need to be strict, and IVF centers will be able to be flexible in their cryopreservation strategies to avoid overloading the laboratory.

한글 요약

2018년 1월부터 2022년 10월까지 2,868건의 동결-해동 배아 이식 사례를 분석한 연구에 따르면, 배아 해동 시간을 오전(24시간 배양) 또는 오후(16시간 배양)로 나누어 비교했을 때 전체 임신율(오전 55.8% vs. 오후 55.0%)과 유산율(오전 9% vs. 오후 10.9%)에서 유의미한 차이가 없었습니다. 난할기 및 배반포기 배아 이식 모두에서 해동 시간에 따른 임신율과 유산율은 유사하게 나타났으며, 환자 연령, 이식 배아 수, 자궁 내막 두께 등은 그룹 간에 차이가 없었습니다. 이 연구는 동결-해동 배아 이식 시 해동 시간을 엄격하게 준수할 필요가 없으며, 난임 센터가 실험실 과부하를 피하기 위해 동결보존 전략을 유연하게 운영할 수 있음을 시사합니다.

2023년도 대한생식의학회 (KSRM) Even poor grade morula has a better clinical outcome than grade I cleavage stage embryo in vitrified-warmed ET (VWE). (동결배아 이식에서 1등급의 난할기 단계 배아 보다 낮은 등급의 상실배 단계의 배아가 더 나은 임상적 결과를 보였다)

HyeYoon Kim, JunSang Park, GaWon Kim, HoJeong Son , MinJi Kim, , GyeongDeok Heo, SeokGi Kim, JiYun Seong, HyeKyung Noh, KyeongHo Lee
Mamapapa&Baby Ob/Gy clinic, Baby dream research center, Ulsan, Korea- South.

Objective

A study to find out which embryo should be transferred to better clinical outcomes in VWE between poor grad morula and grade I cleavage stage embryo.

Summary of answer

Cryo-loop with high thermal conductivity significantly improved the rate of intact embryos after thawing and clinical outcomes compared to Hemi-straw.

Materials and Methods

The non-donors in the transfer cycles of vitrified-warmed day 3 embryo transfer cycles performed from January 2020 through August 2022(n=367) were included in this study. A total of 367 patients was performed embryo transfer. Poor grade morula was transferred 251 cases and grade I cleavage stage embryo was transferred 116 cases. We evaluated grade I as the top grade and grade III or lower as the poor grade. Day 3 embryos were vitrified with Cryo-loop. After thawing, the embryos were cultured in vitro for overnight to observe their subsequent development and select them. When the embryo was transferred, the morula group excluded grade I morula and the cleavage stage embryo group included at least one grade I cleavage stage embryo. After embryo transfer, the pregnancy rate were compared the poor grade morula and grade I cleavage stage embryo

Results

Patient characteristics were similar in the two groups. In each group, age (poor grade morula: 37.9±3.9 vs. grade I cleavage stage: 38.6±4.2 P=0.12), endometrial thickness (10.1±2.2 vs. 10.1±2.6mm p=0.88) and the number of embryo transferred (2.0±0.5 vs. 2.0±0.5 p=0.52) did not show significant differences. Total pregnancy rate was 50.7% (186/367). The pregnancy rate of the poor grade morula transfer group was significantly higher than the rate of the grade I cleavage stage embryo transfer group (56.6 (142/251) vs. 37.9% (44/116) p<0.05). The same tendency was observed when the pregnancy rate was divided into those aged 38 years or older (43.7 (52/119) vs. 32.4% (22/48)) and younger than 38 years old (68.2 (90/132) vs. 45.8% (22/68)).

Conclusions

Transfer of poor grade morula has a better clinical outcome than transfer of grade I cleavage stage embryo in VWE. But Not all grade I cleavage stage embryos develop into blastocysts. The selection of embryos showing signs of compaction in VWE may be a more important predictor of pregnancy than grade. This is because even a poor morula has a higher chance of developing into a blastocyst than cleavage stage embryo.

한글 요약

동결-해동 배아 이식(VWE) 시 낮은 등급의 상실배(morula)가 1등급 난할기 배아보다 더 나은 임상 결과를 보이는지 알아보기 위한 연구가 진행되었습니다. Day 3 배아를 동결 후 해동하여 하룻밤 배양한 뒤 선택했으며, 상실배 그룹에서는 1등급 상실배를 제외하고, 난할기 배아 그룹에서는 최소한 하나의 1등급 난할기 배아가 포함되었습니다. 환자 특성은 두 그룹 간에 유사했으며, 나이, 자궁내막 두께, 이식된 배아 수에서 유의미한 차이는 없었습니다. 연구 결과, 전체 임신율은 50.7%였고, 낮은 등급의 상실배를 이식한 그룹의 임신율(56.6%)이 1등급 난할기 배아를 이식한 그룹(37.9%)보다 유의하게 높았습니다 (p<0.05). 이러한 경향은 38세 이상과 38세 미만 연령대에서도 동일하게 관찰되었습니다. 따라서 이 연구는 동결-해동 배아 이식 시 낮은 등급의 상실배 이식이 1등급 난할기 배아 이식보다 더 좋은 임상 결과를 보인다고 결론 내렸습니다.