Clinical and Experimental Reproductive Medicine

The Korean Society for Reproductive Medicine (대한생식의학회)
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Clinical Study on the Successful Pregnancy and Delivery after Transfer of Human Blastocysts Cryopreserved by Vitrification

인간 포배란의 유리화동결 융해 후 임신 및 분만에 관한 연구

  • Choi, Dong-Hee (Department of Obstetrics and Gynecology, Pochon Cha University, Infertiliy Medical Center of Cha General Hospital) ;
  • Chung, Hyung-Min (Infertiliy Medical Center of Cha General Hospital) ;
  • Chung, Mi-Kyung (Infertiliy Medical Center of Cha General Hospital) ;
  • Lee, Sook-Hwan (Department of Obstetrics and Gynecology, Pochon Cha University, Infertiliy Medical Center of Cha General Hospital) ;
  • Nam, Yoon-Seung (Department of Obstetrics and Gynecology, Pochon Cha University, Infertiliy Medical Center of Cha General Hospital) ;
  • Park, Chan (Department of Obstetrics and Gynecology, Pochon Cha University, Infertiliy Medical Center of Cha General Hospital) ;
  • Kwak, In-Pyung (Department of Obstetrics and Gynecology, Pochon Cha University, Infertiliy Medical Center of Cha General Hospital) ;
  • Yoon, Tae-Ki (Department of Obstetrics and Gynecology, Pochon Cha University, Infertiliy Medical Center of Cha General Hospital)
  • 최동희 (포천중문의과대학 산부인과학교실, 차병원 여성의학연구소) ;
  • 정형민 (차병원 여성의학연구소) ;
  • 정미경 (차병원 여성의학연구소) ;
  • 이숙환 (포천중문의과대학 산부인과학교실, 차병원 여성의학연구소) ;
  • 남윤성 (포천중문의과대학 산부인과학교실, 차병원 여성의학연구소) ;
  • 박찬 (포천중문의과대학 산부인과학교실, 차병원 여성의학연구소) ;
  • 곽인평 (포천중문의과대학 산부인과학교실, 차병원 여성의학연구소) ;
  • 윤태기 (포천중문의과대학 산부인과학교실, 차병원 여성의학연구소)
  • Published : 2000.12.30
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Abstract

Objective: This study was performed to evaluate whether vitrification method could be used for the cryopreservation of human blastocysts derived from IVF program. Methods: Surplus embryos were obtained from consented IVF patients. Controlled ovarian hyperstimulation was done with midluteal GnRH agonist, gonadotropin and hCG. After oocyte retrieval and insemination, fresh embryo transfer was done at $4{\sim}8$ cell stage. The surplus embryos after ET were cultured in blastocyst medium up to 6 days after oocyte retrieval. Obtained blastocysts were cryopreserved with our vitrification method. Blastocysts were exposed to 1.5 Methylene glycol (EG) in phosphate buffered saline (PBS) for 2.5 minutes, followed by 5.5 M EG plus 1 M sucrose for 20 seconds. Then 1 to 3 blastocysts were mounted on electron microscope (EM) grid and the grid was plunged into liquid nitrogen for storage. For thawing, blastocyst-containing EM grids were sequentially transferred in 1.0 M, 0.5 M, 0.25 M, 0.125 M and 0 M sucrose solution at the intervals of2.5 minutes. And blastocysts were cultured for about 6 hours and only re-expanded blastocysts were transferred to uterus of the patients on 4 to 5 days after ovulation in natural cycle or on 18 to 19 day of artificial cycle. Results: From Oct. 1998 to Jul. 1999, 34 patients were agreed to participate in this study. The mean age and duration of infertility of the patients were 31.6 years and 4.1 years, respectively. Among 34 cycles. replacements could be done in 20 cycles (58.8%). A total 93 blastocysts were thawed and 48 (51.6%) of them survived. Thirty-eight blastocysts, mean 1.9 embryos per patient, were transferred, resulting in 5 clinical pregnancies which consisted of 1 triplet, 2 sets of twins and 2 singleton pregnancies. The pregnancy rate per transfer was 25% and implantation rate was 23.6%. Five patients delivered 7 healthy babies including 2 sets of twins at term. Conclusion: Successful pregnancies and deliveries were established after transfer of vitrified human blastocysts. Vitrification using ethylene glycol as cryoprotectant and electron microscope grid is a rapid and simple method that can be effectively applied for the cryopreservation of human blastocysts.

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