Frozen Embryo Transfer
Often after a cycle of IVF, ICSI or GIFT, there are embryos of a suitable quality that can be frozen and stored for future use. Whether your fresh cycle was successful or unsuccessful, frozen embryo replacement gives you the chance of a pregnancy. At the CRGH, we use a technique called vitrification to freeze eggs and embryos. Vitrification involves the quick freeze technique, which reduces ice-crystal formation inside the embryos thereby increasing the possibility of a successful thaw. Our current data shows that our success rates with frozen/thawed embryos are as good as our success rates with fresh embryos. In a frozen/thawed cycle, it is sometimes easier to prepare the womb for the embryo than in a fresh cycle – which may lead to more success.
At the beginning of a frozen/thaw cycle, it is essential that both partners attend the CRGH to read and sign the consent to thaw and transfer the embryos. This procedure cannot proceed without both partners consenting. Frozen/thawed embryos can be replaced in a natural or medicated cycle.
A natural cycle involves monitoring the period and transferring the embryo at the optimal time after ovulation has been observed to mimic nature as closely as possible. Progesterone to support the lining is administered after the transfer.
For a medicated cycle we suppress the body's hormone production and then we scan the patient. We then administer oestrogen (topical, oral, vaginal or a combination) and the womb lining is monitored. Once the lining has reached an appropriate thickness, progesterone is administered either through injections or pessaries and starting a specific number of days prior to transfer. This time-frame is dictated by the stage the embryo was frozen at.
