A modified embryo cryopreservation method increases post-thaw survival with a concomitant increase in implantation.
OBJECTIVE
To achieve maximum post-thaw survival of frozen embryos.


METHODS
Historical controlled study.


METHODS
Hospital-based fertility center.


METHODS
One hundred forty-five patients whose embryos were frozen and thawed according to the standard method, and 56 patients whose embryos were frozen and thawed according to a modified method.


METHODS
Modifications were made to the various steps of cryopreservation: freezing and thawing solutions, loading of embryos into the straws, and warming rates.


METHODS
Post-thaw survival, implantation, and pregnancy rates.


RESULTS
With the modified method, 138 (93%) of the 149 embryos thawed for 56 patients survived freezing, and 79.8% had all their blastomeres intact, which is almost double the result obtained (41.8%) for patients whose embryos were thawed with the standard method. The implantation and pregnancy rates were also significantly higher with the modified method compared with the standard method.


CONCLUSIONS
Greater post-thaw embryo survival was achieved, with a concomitant increase in implantation and pregnancy rates, by modifying the various steps in the standard cryopreservation methodology. This has important implications in IVF practice.
Kattera
Suresh
S
Centre for Reproductive Medicine and Gleneagles IVF Centre, Gleneagles Hospital, Singapore. suresh@cccrm.com
Chen
Christopher
C
D000328:Adult; D015925:Cryopreservation / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D010064:Embryo Implantation / Q000502:physiology; D004622:Embryo, Mammalian / Q000166:cytology* / Q000502:physiology; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*