Cryopreservation
is a technique in which sperms, eggs and embryos are froozen at a sub-zero temperature
to preserve them for future when the need arises. There are 3 types of Cryopreservation
in IVF spectrum: 1) Sperm Cryopreservation 2) Eggs Cryopreservation 3) Embryos Cryopreservation
Sperm Cryopreservation:
Sperm are frozen to preserve because of a string of reasons: a) To develop sperm
bank; b) To donate stored sperm; c) To use it during the treatment if the male partner
is unable to ejaculate on the stipulated day; d) Before undergoing vasectomy; e)
Prior to Cancer treatment which might adversely affect fertility; f) Retrieved sperms
from epididymis (PESA) or testes (TESA).
If sperm are frozen for the impending treatment of the donor, the storage period
is usually 1 year. For the pre-chemotherapy storage, the duration is mostly of 10
years which can be extended in certain circumstances.
Eggs (oocytes) Cryopreservation:
Eggs Cryopreservation is for women who are about to undergo medical treatment for
ailments such as cancer etc. which may affect her ability to produce eggs in the
future. This technique is also useful for women who are career-oriented and does
not want early motherhood. Eggs are frozen within few hours of collection through
the standard freezing process. Later, when women are ready to be pregnant, the frozen
eggs are thawed, fertilized with the husbands’ sperms and resultant embryo is implanted
in the uterus.
Embryos Cryopreservation:
During the treatments like IVF, ICSI the best embryos are selected and transferred
during the first cycle, if any good quality ‘surplus’ embryos are left, they are
frozen to preserve for the future use while curing infertile couples. It is to be
noted that only the embryos of top-notch quality survive the freezing and thawing
process.