title: Ultrarapid cryopreservation of human embryos: experience with 1,582 embryos.
abstract: OBJECTIVE
  To demonstrate the effectiveness of ultrarapid cryopreservation in human embryos.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  An IVF unit of a medical center.
  
  
  METHODS
  All cases received ultrarapid freezing (URF) of embryos and frozen embryo transfer.
  
  
  METHODS
  Embryos were placed in phosphate-buffered saline (PB1) + 20% maternal serum (MS) for 5 minutes. Embryos were loaded to the straws containing PB1 + MS + 0.25 M sucrose (SUC) + 3.5 M dimethyl sulfoxide for 3 minutes, and then were stored in a liquid nitrogen tank. Embryos were thawed in a 37 degrees C water for 6 seconds and then cultured in PB1 + MS + SUC for 10 minutes. Embryos were transferred into PB1 + MS for 5 minutes and were transferred into patients.
  
  
  METHODS
  The embryo grades before and after URF, the survival and transferred embryo numbers, and the pregnancy and abortion rates were analyzed.
  
  
  RESULTS
  A total of 1,582 embryos were thawed, of which 1,273 (80.5%) embryos were transferred and 1,032 (65.2%) embryos survived with > or = 50% intact blastomere. The embryo numbers with grade I or II before and after freezing and thawing were 1,110 (70.2%) and 790 (50.0%). The mean embryo numbers per transfer was 5.0. Twenty-eight pregnancies (11.4% per transfer) were established, which included 5 miscarriages, 1 ectopic pregnancy, 4 preterm and 18 term deliveries.
  
  
  CONCLUSIONS
  Ultrarapid freezing is worthy of reconsideration for embryo cryopreservation.
authors.affiliation: Department of Obstetrics and Gynecology, China Medical College Hospital, Taichung, Taiwan, Republic of China.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Hsieh
authors.forename: H D
authors.initials: HD
authors.lastname: Tsai
authors.forename: C C
authors.initials: CC
authors.lastname: Chang
authors.forename: C C
authors.initials: CC
authors.lastname: Chang
authors.forename: H Y
authors.initials: HY
authors.lastname: Lo
authors.forename: A C
authors.initials: AC
authors.lastname: Lai
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology; D001757:Blastomeres / Q000166:cytology / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods*; D004121:Dimethyl Sulfoxide; D004622:Embryo, Mammalian / Q000166:cytology / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy / Q000706:statistics & numerical data*; D011271:Pregnancy, Ectopic / Q000453:epidemiology; D012189:Retrospective Studies; D013395:Sucrose
chemical_list: D013395:Sucrose; D004121:Dimethyl Sulfoxide