2024년도 대한생식의학회 (KSRM) Increasing the number of embryos transferred does not improve pregnancy rates in patients over 40 years of age. (40세 이상 환자의 배아 이식 개수 증가는 임신율을 개선하지 않는다)

Ho Jeong Son¹, Seok Gi Kim¹, Min Ji Kim¹, Ga Won Kim¹, Gyeong Deok Heo¹, Hye Yoon Kim¹, Ye Won Kim¹, Jae Hun Choi¹, Ji Yun Seong², Hye Kyung Noh², Kyeong Ho Lee²
¹Mamapapa&Baby Baby dream research center, ²Mamapapa&Baby Ob/Gy clinic

Objective

The objectives of the study are: Would increasing the number of embryos transferred help improve pregnancy rates in patients over 40 years of age?

Methods

This retrospective study was performed on, 1152 frozen-thawed embryo transfer cases performed from January 2016 to December 2023. Total 2198 embryos were divided into two groups according to transfer number (cleavage stage embryo transfer 2, 3 and blastocyst stage embryo transfer 1, 2). 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=720: transfer 2, 525; transfer 3, 195) or the blastocyst stage (n=432: transfer 1, 301; transfer 2, 131). Based on following cases, the pregnancy, miscarriage rate, G-sac(1>) were calculated respectively.

Results

There were no differences in patients age (cleavage embryo transfer 2, 41.90±2.5 vs transfer 3, 42.1±2.4 and blastocyst embryo transfer 1, 41.6±1.9 vs transfer 2, 41.8±2.2), and endometrial thickness (cleavage embryo transfer 2, 9.6.±5.8 vs transfer 3, 9.6±6.5 and blastocyst embryo transfer 1, 9.9±5.4 vs transfer 2, 9.7±4.9). The clinical pregnancy rates were cleavage stage (transfer 2, 34.1% (179/525) vs transfer 3, 33.3% (65/195) p=0.91) and blastocyst stage (transfer 1, 49.8% (150/301) vs transfer 2, 47.3% (62/131) p=0.7). In addition, the miscarriage rate was cleavage stage (transfer 2, 10.6% (19/179) vs transfer 3, 13.8% (9/65) p=0.63) and blastocyst stage (transfer 1, 16.0% (24/126) vs transfer 2, 9.1% (5/55) p=0.3). The G-sac(1>) rate were cleavage stage (transfer 2, 22.4% (28/125) vs transfer 3, 30.8% (16/52) p=0.32) and blastocyst stage (transfer 1, 0.0% (0/96) vs transfer 2, 45.9% (17/37) p=0.001<).

Conclusion

In patients over 40 years of age, increasing the number of embryos transferred did not improve IVF outcomes, and multiple pregnancies significantly increased in 5-day transfers. Therefore, increasing the number of FETs rather than increasing the number of embryos transferred may be more effective in improving the chances of pregnancy.

한글요약

40세 이상 환자에서 이식하는 배아 수를 늘리는 것이 임신율을 개선하는지 알아본 이 후향적 연구는 2016년 1월부터 2023년 12월까지 1,152건의 동결-해동 배아 이식 사례를 분석했습니다. 연구는 2개 또는 3개의 할구기 배아를 이식한 그룹(각각 525건, 195건)과 1개 또는 2개의 배반포를 이식한 그룹(각각 301건, 131건)으로 나누어 임신율, 유산율, 그리고 단일 태낭(G-sac 1>)률을 비교시 그룹 간 임신율과 유산율에 통계적 차이가 없음을 확인했습니다. 오히려 5일차(배반포) 이식에서 다태 임신 위험을 유의하게 증가시켰습니다. 따라서 40세 이상 여성의 임신 성공율을 높이기 위해 이식 배아 수를 늘리기보다 동결 배아 이식(FET) 횟수를 늘리는 것이 더 효과적인 전략일 수 있다고 제안합니다.