Patients who undergo IVF treatments may have several eggs collected. The mature eggs are then fertilised with sperm and assessed for fertilisation. Fertilised eggs are cultured and monitored for development up till the time for their transfer back to the patients’ uterus.
A patient may have multiple high quality embryos eligible for embryo transfer but usually only one or two embryos are chosen for transfer and the surplus of high quality embryos can be cryopreserved (frozen) for future use. Many studies also suggest that there is evidence that IVF outcomes may be improved by performing Frozen Embryo Transfer (FET) compared with fresh embryo transfer. This could be explained by a better embryo-endometrium synchrony achieved with endometrium preparation cycles.
Vitrification is a cutting edge technology for cryopreservation of embryos and is the method of choice available at Raffles Fertility Centre. It allows freezing of spare embryos with better post-thaw survival rates when compared with older methods.
The older slow-freezing method involves slowly cooling the embryos to -30oC in a specialised freezer before storing in -196oC in liquid nitrogen tanks. During this procedure, the formation of intracellular ice crystals inside the cells can damage the embryo which will result in lower embryo survival chances.
Through vitrification, water molecules in the cells are removed and replaced with cryoprotectant and the embryo is plunged directly into liquid nitrogen creating a drastic drop in temperature. This quick freezing eliminates the chance for intracellular ice crystals to be formed, thus decreasing the chance for damaging the embryos during the thawing process.
The vitrification method therefore translates into a higher chance for the thawed embryos to implant into the uterus and therefore, potentially better pregnancy rates. At Raffles Fertility Center, we are excited to offer this cutting edge technology to all patients who chose to cryopreserve their embryos.