Excess embryos of good quality that are not transferred can be cryopreserved (frozen). These embryos can be transferred into the uterus in a subsequent unstimulated cycle for another chance of pregnancy.

Cryopreservation is a process whereby embryos may be frozen and stored in liquid nitrogen at -196 degrees Celsius for replacement in a subsequent treatment cycle (called a Thaw Cycle). Cryopreservation and later transfer of extra embryos give couples an additional chance to become pregnant following egg retrieval in an IVF/ICSI cycle.

For a Spontaneous Thaw Cycle (STC): (slow freezing method)

• Number of visits to centre: 5 to 8 per cycle
• Clinical pregnancy rate per embryo transfer at TMC Fertility Centre is 36.8%

Our first Vitrification Freeze-Thaw Blastocyst Pregnancy April 2007

We are the first centre in Malaysia to utilize Vitrification Kit for screening of embryos. Our first attempt if vitrification resulted in pregnancy on April 2007

Vitrification is an alternative to slow freezing especially in the freezing of blastocysts and oocytes. Since chilling injury to oocytes / blastocyts is time dependent, the rationale is to prevent ice formation and injury by cooling at a rate fast enough to solidify the intracellular water before it can crystallize.

Therefore, one important aspect of vitrification is the ability to vitrify (cool) and warm quickly enough to avoid crystal formation.

Vitrification is also known to have higher survival rate for blastocyst and oocyte cryopreservation compared to the conventional slow-freezing method. We are now using this technique routinely for blastocyst freezing.

• FET success rates