Before 2007, freezing of embryos was done with slow freezing, where embryos are put in a media & subjected to progressively decreasing temperatures sequentially. However it didn’t yield more than 20% success rate. Besides freezing is time consuming & there was unavailability of dedicated in-house embryologists.
Since 2008, Vitrification a new technique for freezing, was well accepted. Vitrification ensured minimal damage to the embryos because of lack of ice-crystal formation. Moreover, the embryos had a far higher recovery rate & survival rate after Vitrification resulting in higher frequency rate.
Q. Why does freezing give more results & what is the need for freezing?
A. If Vitrification department of any IVF centre isn’t up to the mark, it’s impossible to give more than 30-35% results among three fresh cycle attempts. When the hormonal stimulation is done in women for Ovum pick-up, multiple follicles release high amount of estrogen, decreasing the chances of success. Good freezing protocol is must in any IVF clinic. At WINGS, we recommend freeze-all embryos to almost 85% of our patients.
Q. What is the success rate in Freeze-Thaw embryo transfers?
A. The tentative success rate is 55%, always more than fresh embryo transfers. Success rates will be around 95% if we have enough embryo to transfer thrice. Apart from the reduced cost of treatment, there’s no agony of multiple hormonal stimulations & needle pricks.
Q. What are the tangible benefits of frozen embryo transfer?
A. There are less chances of chemical pregnancy & ectopic pregnancy, apart from reduced costs & less mental agony. Such patients have babies with higher birth weight & lower prematurity.