Cryopreservation is a procedure that involves freezing and storing of oocytes, sperms or embryos for a later date. The specimens are stored in liquid nitrogen at -1960C
Women who are diagnosed with cancer and need to undergo chemotherapy and radiation for treatment. These treatments can cause permanent damage to ovaries leading to infertility.
Women who want to delay childbearing in order to pursue educational or career goals. Unlike the ovaries and oocytes, the uterus does not age and therefore cryopreserving oocytes can ensure a chance for future pregnancy.
Eggs are frozen by a highly specialized technique called vitification. Vitrification involves plunging oocytes into liquid nitrogen after exposure to a cryoprotectant solution.
Egg retrieval is similar to IVF where hormone stimulation is given for the growth and maturation of eggs. A needle is passed through the vagina under anesthesia and ultrasonographic guidance. The eggs are retrieved and frozen in a couple of hours.
Eggs can be frozen for long periods without any deterioration in quality. However, due its single cell status egg freezing and survival are even more challenging than embryo freezing.
Sperms are frozen for a variety of reasons. They are preserved if the husband has to travel during the treatment cycle of his wife and can not be present at the time of procedures such as IUI, IVF/ICSI. They are also frozen as a back up sample before IVF.
Patients are required to give a sample with an abstinence of 3-5 days. The specimen is analyzed and cryopreserved in liquid nitrogen at -1960C after mixing with a cryoprotectant solution. This technology allows for the use of sperms in numerous procedures for the purpose of future fertilization and pregnancy.
Sperms can be frozen for an indefinite period of time without compromising its quality.
Patients are required to undergo a viral screening test for HIV ½ antibody, Hep B surface Antigen, and Hep C Antibody and should show negative results for these Sexual abstinence of 3-5 days
Sometimes in IVF, due to stimulation with hormones, a large number of oocytes are retrieved. Subsequently after transfer of good quality embryos into the uterus, surplus good grade embryos may remain. Under such circumstances or when a patient goes into OHSS (ovarian hyperstimulation) after retrieval, cryopreservation of embryos is offered.
Embryos are frozen using a technique called vitrification that has exponentially increased the post thaw survival, implantation and pregnancy rates.
In a majority of fresh cycles, surplus good embryos can be frozen. The embryos are placed in a specialized solution to monitor their growth and development. Our scientist then decides whether they can be frozen or not. The freezing criterion is dependent on the potential of the embryo to survive post thaw as cryopreservation is an aggressive process to the embryo.
The success rates of FET cycle are nearly the same as fresh cycles. Maternal age at the time of embryo freezing remains a primary indicator of pregnancy chance. The potential for success remains the same no matter the amount of time between embryo freezing and thawing. When stored in liquid nitrogen the embryos are frozen in time and do not age.
Women of 37 years and younger can achieve a success rate of 50% per thaw cycle. This rate declines as the maternal age at the time of embryo freezing increases.
Embryos can be frozen for an indefinite period of time as cryopreservation does not have any effect on quality. Renewal of rental period with hospital can ensure storage for as long as the patient desires.
Oocyte freezing is a procedure which consists of freezing viable oocytes (eggs) prior to fertilization. These frozen oocytes can be thawed and fertilized with sperm at some date in future for the purpose of treatment.
It is usually considered for:
Ovarian stimulation and oocyte collection procedures are similar to standard IVF. The oocytes are then frozen within 24 hours of collection. At any later date, they can be thawed and injected with sperm as in ICSI (Intracytoplasmic Sperm Injection) to achieve fertilization. The timing, preparation of uterine cavity and embryo transfer are as for frozen-embryo transfers.
Oocyte freezing is still considered to be in its experimental stage. In comparision with frozen embryo cycles, oocyte freeze/thaw cases are much lower in number due to the poor survival rate of oocytes. However, after the introduction of Vitrification, the technique has significantly improved.
Sperms can be frozen for a number of reasons: