Oocyte freezing or egg freezing is a relatively new treatment where in the ovaries are stimulated with hormonal medications for about 8-10 days, follicular growth is monitored by serial scans and blood tests. Once the follicles are ready, a HCG trigger is given and Oocyte retrieval is planned after 36 hrs. These Oocytes are vitrified and stored in liquid nitrogen at -180 degrees.Oocyte freezing may be considered:
- If you are diagnosed with a cancer requiring chemotherapy or radiotherapy which is likely to destroy the ovarian reserve.
- If you are concerned about your age but are not yet ready to bear children.
Once you decide to go ahead with egg donation, you have to register in the donor bank who would provide you with an anonymous donor matching your requirements. Neither your identity nor the donor’s identity will be revealed to each other, but you will have access to all the requisite information about the donor.
Oocytes can be stored up to five years subject to periodic renewal of the freezing charges. If you wish to continue beyond that period, the centre has to be intimated about it. If you wish to discontinue before five years, again you have to intimate the centre and you have the option of either discarding them or donating them for research or donating them for third party reproduction (as an anonymous donor).
Once you decide use the frozen Oocytes, your endometrium is prepared with hormones similar to the frozen embryo transfer cycle. The vitrified Oocytes are thawed at appropriate time and ICSI is done. The resulting embryos are cultured for 3-5 days and then transferred.
Oocyte freezing is not as efficient as embryo freezing and results in a much lower survival rates as the embryo freezing. The success rates are much less than the fresh or frozen embryo transfer and vary from centre to centre.