Embryo Freezing

Embryo Freezing

This is a procedure which is used to freeze either surplus embryos or to freeze all embryos of an IVF cycle These embryos can be cryopreserved by freezing them in the laboratory using specialized freezing equipment and the embryos can then be safely stored in liquid nitrogen. The method used in our lab is called vitrification. Through a series of carefully orchestrated steps, the embryos are ultimately frozen at temperature of minus 196 degrees below zero leaving them in a state of suspended animation in which they can remain for many years. Even embryos that have been stored for more than 5-6 years have successfully generated pregnancies (although most patients tend to use their frozen embryos within 3 to 5 years after they are frozen). We have successfully given pregnancy to a lady with enbryos frozen in our lab 9 years back.

(https://timesofindia.indiatimes.com/city/delhi/embryo-frozen-for-9-years-used-for-ivf-birth/articleshow/67169513.cms) The pregnancy rates associated with replacing frozen embryos depend on the age of the patient and the quality of the embryos at the time of cryopreservation.

Freezing embryos is appropriate for:

  • Women who have made more than 3 embryos(surplus) during an IVF cycle.
  • Couples facing cancer treatment that may affect the eggs or sperm quality.
  • Frozen Embryos can be used for next pregnancy
  • It also permits the uterus environment to return to normal after the process of egg retrieval.
  • Couple can also opt for genetic screening of these embryos.
  • It’s a good preventive step for OHSS in cases of PCOS. We are routinely following this for our cases of Polycystic ovaries.
  • If the uterine lining is not good, it’s a good option to freeze the embryos. Bloom IVF group is one of the first ones in starting vitrification programmes in India.
  • Freeze all : overall the success rates of frozen thaw embryo transfers are better than those of fresh embryo transfer. Many times it is better not to transfer in the same fresh cycle and transfer in the next cycle for getting better results . This is called freeze all.

Step-by-Step Procedure of Embryo Freezing

Creation of embryos by conventional IVF/ICSI cycle
Culture of the embryos for 3 to 5 days
The created embryos are frozen using a technique called VITRIFICATION as explained above. This rapid cooling avoids formation of ice crystals and prevents damage to the crystals.
These embryos are stored in specialized tanks which are filled with liquid nitrogen to maintain them.

Common Questions

If you could not find an answer to your query, please contact us.

The embryos can be easily stored for a period of 10 years. In the recent time a baby has been delivered using embryos that were frozen 27 years ago!
The chances are 37 to 38% per cycle. The cumulative success rates can go upto 60% in three cycles.
The chances of abnormalities with frozen cycle and fresh cycles are the same and there are comparable to the chances of age related abnormalities with general population.
The con is a few percentage of the embryos may be lost in the thawing process.