Cryopreservation or freezing is the process to preserve biological material e.g. egg, sperm, embryo or gonadal tissue at extremely low temperature. Vitrification is an ultra-rapid method of freezing where formation of intracellular ice crystal is totally prevented. The biological material is stored at -196֯ C in liquid nitrogen. At such low temperature all biological activity of living material is stopped and whenever it is taken out at normal temperature, all the cellular activities resume. The purpose of cryopreservation is to store the egg/sperm/embryo for later use. In assisted reproduction there are various indications for cryopreservation. DREAMZ IVF has a very good cryopreservation program where we have achieved 100% post warming recovery of the frozen genetic material.
Fertility preservation is cryopreservation of gametes, embryos or gonadal tissue in order to preserve future fertility. Men and women who want to delay parenthood due to social reason or if they are undergoing treatment for a medical or surgical condition which may hamper their reproductive capacity, can consider fertility preservation.
SPERM FREEZING
Sperm freezing is an effective way to store semen sample for later use. Men can store semen sample by ejaculation or surgically retrieved sperms through PESA/TESA. Couples, who require donor semen for fertility treatment, also get frozen sperms from the semen bank.
Indications of semen freezing:
- Back up semen freezing: If male partner is out of station or unable to procure semen sample at the time of ART procedure
- Very poor semen parameters
- PESA/TESA SAMPLES
- Fertility preservation in cancer patients or any other medical condition
- Donor semen/semen banking
Semen sample is collected under sterile conditions and screened for the sperm count, motility & morphology. Then semen sample is either frozen using slow freezing or vitrification method. The quality of frozen sperms is almost same as before freezing. Studies have shown that babies born after use of frozen semen do not have any birth defects.
EGG FREEZING/OOCYTE FREEZING
As women ages, there is decline in the number and quality of eggs in her ovaries which lead to decreased chances of pregnancy, increased risk of miscarriage and birth defects in the child born. Egg freezing is a boon for women who want to delay motherhood for social or any medical reason. Egg freezing is also used for egg donation cycles.
In egg freezing first the ovarian reserve of the women is assessed. Then she is given hormonal injections for 8 to 12 days to produce more number of eggs and the monitoring is done with trans-vaginal ultrasound. When we get the desired response, the woman is given ovulatory trigger and after 34-36 hours of this injection, the eggs are taken out from the ovaries through ultrasound guided special needle under short anesthesia. Then eggs are denuded to screen out mature eggs and these unfertilized eggs are frozen using vitrification method. They can be stored up to 10 years.
When the woman is ready for pregnancy, these eggs are warmed and inseminated with partner’s sperms through ICSI. The embryos thus formed are transferred back to her uterus.
DREAMZ IVF has > 80% post thaw survival and fertilization rate of frozen oocytes and the pregnancy rate are comparable to fresh oocytes.
EMBRYO FREEZING
Embryo freezing has become an integral part of IVF cycles. With the latest developments in cryopreservation techniques, we are able to achieve 100% post warming recovery and excellent pregnancy rates with frozen embryos. There are certain situations where embryo freezing is indicated:
- Excess good quality embryos formed during an IVF cycle can be stored and later utilized to take another attempt without undergoing the complete cycle of hormonal injections and egg collection.
- If the endometrial lining is inadequate then also embryos are frozen and transferred later.
- In women with PCOS, who have higher risk of ovarian hyper-stimulation, all the embryos are frozen in order to prevent complications.
- Fertility preservation
- PGT cycles
When woman is ready for embryo transfer, the embryos are warmed and replaced in the uterus. Embryo freezing is safe and have no adverse effects on the woman and her baby. As per ICMR guidelines embryos can be stored up to 5 years.
FROZEN EMBRYO TRANSFER
FET or frozen embryo transfer is the process where the embryos frozen from previous cycle are warmed and transferred in the uterus. It can be done in a natural or a hormone replacement cycle. The purpose of either is to get a receptive endometrium. The growth and pattern of endometrium is studied through serial trans-vaginal ultrasound. When the endometrium is adequately prepared, the embryos are taken out from -196֯ C and cultured for few hours at 37֯C before transferring in the uterus. After the embryo transfer, medications and precautions are advised in a manner similar to fresh transfer. At DREAMZ IVF, pregnancy rate with frozen embryos is at par with fresh embryos.