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|Scopus||Web of Science®||Altmetric|
|Title:||Changing the start temperature and cooling rate in a slow-freezing protocol increases human blastocyst viability|
|Citation:||Fertility and Sterility, 2003; 79(2):407-410|
|Publisher:||Elsevier Science Inc|
|David K. Gardner, Michelle Lane, John Stevens and William B. Schoolcraft|
|Abstract:||OBJECTIVE:To determine the effect of start temperature and cooling rate of a slow freezing protocol on human blastocyst viability. DESIGN:Controlled-rate freezing of human blastocysts using different start temperatures and cooling rates. SETTING:Private assisted reproductive technology unit. PATIENT(S):Patients donated with consent cryopreserved pronucleate embryos. INTERVENTION(S):Culture of thawed pronucleate embryos in G III series media, containing hyaluronan, followed by cryopreservation of 36 blastocysts with subsequent noninvasive analysis of embryo metabolism. MAIN OUTCOME MEASURE(S):Pyruvate and glucose consumption and blastocyst reexpansion and quality. RESULT(S):Glucose consumption and blastocyst reexpansion after thaw were significantly higher when a start temperature of -6 degrees C and a cooling rate of 0.5 degrees C/min to -32 degrees C were used compared with a start temperature of 20 degrees C and a cooling rate of 2 degrees C to -6 degrees C, followed by cooling at 0.3 degrees C to -35 degrees C. Pyruvate uptake after thaw was not affected by the freezing procedure. Clinical use of the lower start temperature and quicker cooling rate, combined with culture in hyaluronan-based media, has led to the establishment of a 30% implantation rate. CONCLUSION(S):Human embryos cultured to the blastocyst stage in hyaluronan-based sequential media are readily cryopreserved and maintain their viability after thaw.|
|Keywords:||Blastocyst; cryopreservation; culture; embryo; IVF; viability|
|Appears in Collections:||Obstetrics and Gynaecology publications|
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