title: Vitrification of human early cavitating and deflated expanded blastocysts: clinical outcome of 474 cycles.
abstract: OBJECTIVE
  The present study was undertaken to evaluate and compare the post thaw survival, implantation and pregnancy rates of vitrified human early cavitating blastocysts with deflated expanded blastocysts.
  
  
  METHODS
  Supernumerary blastocysts were vitrified in 30% ethylene glycol-dimethyl sulphoxide based solution using cryoloop. Fully expanded blastocysts were deflated by gentle aspiration of the blastocoelic fluid using a micromanipulator until the cavity collapses prior to vitrification.
  
  
  RESULTS
  Of the 576 vitrified blastocysts, 545 (94.61%) survived thawing in the early cavitating blastocyst group which was significantly higher than deflated expanded blastocyst group, in which only 370 survived thawing out of 459 (80.62%). However, no significant difference was observed in implantation and pregnancy rates between early cavitating and deflated expanded blastocyst groups.
  
  
  CONCLUSIONS
  Early cavitating blastocyst would be the ideal stage for cryopreservation of human blastocysts as it has higher survival rate and avoids additional invasive procedures like deflation of the blastocoele.
authors.affiliation: Embryology Division, Krishna IVF Clinic, Zillaparishad Junction, Visakhapatnam, Pincode-530 002, Andhra Pradesh, India. krishnaivf@hotmail.com
authors.forename: G A Rama
authors.initials: GA
authors.lastname: Raju
authors.forename: G Jaya
authors.initials: GJ
authors.lastname: Prakash
authors.forename: K Murali
authors.initials: KM
authors.lastname: Krishna
authors.forename: K
authors.initials: K
authors.lastname: Madan
mesh_terms: D001755:Blastocyst / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods*; D046508:Culture Techniques; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D010064:Embryo Implantation; D019855:Ethylene Glycol / Q000494:pharmacology; D005260:Female; D006801:Humans; D011247:Pregnancy; D018873:Pregnancy Rate; D016019:Survival Analysis
chemical_list: D019855:Ethylene Glycol; D004121:Dimethyl Sulfoxide