title: Effect of different rehydration temperatures on the survival of human vitrified-warmed oocytes.
abstract: OBJECTIVE
  To evaluate the effect of different exposure temperatures during the dilution process on the survival rate of vitrified oocytes and following development.
  
  
  METHODS
  Patients were divided at random into two groups for different dilution temperature (20-22 °C, RT group; 37 °C,37 °C group) according to computer-generated random numbers on the day of oocyte warming. The survival and fertilization rates of vitrified oocytes as well as the implantation and clinical pregnancy rates of the resulting embryos were recorded.
  
  
  RESULTS
  A total of 662 and 676 oocytes were warmed in the 37 °C group and RT group, respectively, and significant difference was observed in the survival rate between 37 °C group (88.37%) and RT group (79.88%) (P = 0.0000). There was significant difference between the survival rate of 37 °C group (87.27%) and RT group (75.64%) in nondonor patients (P = 0.0001). Multiple linear regression analysis showed that dilution temperature (β = 0.079, P = 0.017) and clinical outcomes of fresh cycles (β = 0.063, P = 0.001) were significantly and independently associated with survival rate. No significant difference was found between the 37 °C group and RT group in: fertilization rate (66.67 versus 65.37%), implantation rate (20.0 versus 19.46%), clinical pregnancy rate (37.5 versus 35.0%).
  
  
  CONCLUSIONS
  In conclusion, the results of this study give supportive evidence of the application of 37 °C in the dilution process, especially for oocytes of poor quality. Further studies with well-controlled experimental groups are needed to optimize protocols for human oocyte vitrification.
authors.affiliation: Center for Reproductive Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, People's Republic of China.
authors.forename: Gao
authors.initials: G
authors.lastname: Shanshan
authors.forename: Li
authors.initials: L
authors.lastname: Mei
authors.forename: Wu
authors.initials: W
authors.lastname: Keliang
authors.forename: Sheng
authors.initials: S
authors.lastname: Yan
authors.forename: Tang
authors.initials: T
authors.lastname: Rong
authors.forename: Chen
authors.initials: C
authors.lastname: Zi-Jiang
mesh_terms: D000328:Adult; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods*; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data; D006801:Humans; D016014:Linear Models; D050498:Live Birth; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D013696:Temperature; D016896:Treatment Outcome; D058989:Vitrification