Introduction infertility clinic in delhi,india priory clinic - copy
Best IVF Expert India
Dr. S.Basu | Dr. S.N.Basu
• At Priory Clinic, we recognize that several
diverse factors could affect a couple’s fertility;
we also understand how much anxiety
infertility can cause to couples. We have state
of the art facilities at Priory Clinic that help
you to get to the root of the problem. We
strive to provide you with a solution through
various methods. Cryopreservation is one of
the facilities offered at our fertility clinic. Let
me tell you all about it.
Understand what it is
The word ‘Cryo’ comes from the Greek word ‘kruos’, which means icy cold; in the combining form,
it refers to low temperatures. So basically it means preserving in very low temperatures.
This is essentially a process whereby cells, whole tissues, or anything else that is likely to be
damaged due to chemical reactions or the passage of time, are preserved, by cooling them to
extremely low temperatures. In infertility clinics, embryos, gametes, sperms, and ovarian and
testicular tissue are the materials preserved in this manner, for use in the future. This
method is more efficient and cost effective, and more convenient for the couple.
To protect the materials from further damage that may be brought about by ice formation while
freezing, they are usually coated with ‘Cryoprotectants’.
At our clinic it is a two-step process: First, we collect the sample from the couple in special straw
like tubes. Next, they are stored at sub-zero temperatures in special solutions; before use,
these specimens are thawed.
There are several types of Cryopreservation, and they differ in these areas: specimen type,
temperature, type of cryopreservant, freezing and thawing times.
• Improves Efficiency: The extracted sperms, eggs or embryos can be used
whenever needed, saving money, energy and time. The woman does not have
to go through repeated ovarian stimulation; single oocyte retrieval is sufficient.
• Avoids hyper stimulation syndrome: Multiple medical stimulation of the
ovaries is risky and strenuous for the ovaries, and can even cause death in
extreme cases. With this method, that risk is eliminated as stimulation is done
• R & D: Many preserved embryos are used for research; often, a couple
conceives in the first attempt and they donate the rest of the embryos for
• Eliminates need for multiple implants: Earlier, to improve the chances of
conception, multiple implantations were made but nowadays in a single
attempt, only one or maximum two embryos are implanted, with the others
being frozen for later use.
• Preservation of Fertility: Couples facing risk of becoming infertile, like those
undergoing chemotherapy, or women with early menopause genes, can
greatly benefit from preserving their eggs, sperms and embryos for future use.
Cryopreservation is basically a process of freezing human tissues to keep
them ‘live’ for a long period of time. This means that the cells have to be
preserved undamaged, so that once thawed, they can function normally,
and become active. There are several different conventions to be followed
for achieving this.
Cryosurvival refers to the process of thawing the frozen tissues and making
them active again. The necessity of maintaining water movement inside
the cell membrane to ensure the cell’s survival makes this a very
challenging task. In spite of the low external temperature, if water
movement inside the cell is constant, it will maintain the same pressure.
Do bear in mind that all human cells do not have the same structure; the
water movement varies across cells. Hence, it is crucial to determine the
protocol for freezing and thawing, depending on the material being
Let us take a look at the methods of cryopreservation of different cells in our clinic.
1. Gametes: preserving the male gametes is quite simple, as thousands of
sperms are found even in a little semen. Even with less than perfect
preservation techniques, sufficient number of sperms will remain viable.
Survival is nearly double when the semen is taken via the normozoospermic
method as compared to the oligoozoospermic method. Preparation of the
semen is also crucial. The survival rate can be increased by a further 12% -
27% with the ‘swim up’ technique and 23% with the centrifugal technique.
2. Oocytes: Preservation of these cells is far more difficult as eggs are extremely
delicate and their outer shells get injured easily even in spite of the
precautions taken. However, emergent technologies in this field are now
helping us to preserve oocytes much better than before; in fact, the survival
rate is up to 60%. Yet, the incidence of live births with the use of survived
oocytes is still low in comparison to fresh oocytes. One of the innovations has
been the use of rapid freezing; it was observed that slow freezing diminished
the survival chances of the oocyte.
3. Embryos: Embryos can be cryopreserved efficiently and successfully. Research has
shown that while the chance for a live birth through a preserved embryo is around
5%, it could be doubled by preserving blastocytes. In my opinion it is prudent to
fertilize the oocyte in lab, and then freezing it for preservation. Whether or not the
implanted embryo develops into a baby depends on, a) the embryo’s
developmental stage at freezing, and b), the implantation time post thawing. At
Priory Clinic we recommend the freezing of the embryo when it has grown to a
size of over 6 cells. Implantation of such embryos has a higher chance at success.
Waiting for the thawed embryo to commence division and replication before
implanting it, also increases its survival odds.
4. Testicular and Ovarian Tissue: There may be cases where there is paucity of time
for ovarian stimulation or gamete collection; either the patient may not have
reached puberty, or has been prescribed treatment that may cause infertility (like,
say, chemotherapy for cancer). Gonadal tissue is collected to preserve fertility.
However, readers need to understand that this is still in the experimental stage,
and wide success has not yet been reported.