Embryo Freezing and Frozen embryo transfer:
Sperm can be frozen for future use either in artificial insemination or other fertility treatments, or be donated. Donated sperm has to be stored for six months before it can be used in treatment, in order to screen the donor for infection.
It is indicated in
- Cancer patients as a part of the fertility preservation strategy in those who are scheduled for cytotoxic chemotherapy.
- Stored as a backup when patients are undergoing fertility treatment especially when they have low counts/ collection problem or deteriorating semen parameters.
- It is also stored for donation for a period of six months as a part of the donor quarantine for infectious diseases.
After thawing the stored sperms, almost 50% of them do not survive and there is a definite deterioration in the quality of the semen. Depending on the quality of the thawed sample, it can be used either for IUI, IVF or ICSI.
Embryo freezing is a process where in the unused embryos are frozen at -196 degrees in liquid nitrogen using a method called vitrification. The embryos are normally stored up to five years subject to periodic renewal of charges. If you wish to continue beyond that period, the center has to be intimated about it. If you wish to discontinue before five years, again you have to intimate the center 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).
The frozen thawed embryos can be transferred into the uterus either in a natural cycle or in a downregulated cycle.
Natural cycle FET: It can be done if you have ovulatory cycles. Your cycles would be monitored by scans for follicular growth and ovulation and the embryos are transferred at the appropriate time following ovulation.
Downregulated FET: Your natural cycle is suppressed using medications and a period is artificially induced, Followed by hormonal medication to prepare the uterus. Once the lining of the uterus is ready, the embryos are transferred at the appropriate time.
Once the frozen embryos are thawed to room temperature, only about 80-85% of them survive. Upon transferring these embryos the success rate is good as a fresh embryo transfer approximately 50%.