Preserving Oocytes for Delaying Motherhood
In vitro fertilization cycles, it is sometimes necessary to freeze a couple's supernumerary embryos, which are saved for future attempts. The criteria that embryos must meet to be frozen are very demanding since the processes of freezing and thawing can be aggressive for them.
This process does not modify or alter the quality of cryo-preserved embryos.
The technique of vitrification has exponentially increased the number of viable embryos compared to those transferred "fresh", since this freezing technique is very aggressive for embryos (compared to older slow-freezing techniques), which makes it possible to have Very high survival and pregnancy rates.
Patients who have vitrified embryos are contacted every 2 years to confirm that they want to keep their frozen embryos for another try. The embryos belong to them and the mission of the clinic is to ensure their custody.
Why cannot you always freeze the embryos left over from a fresh cycle?
We can freeze embryos in most cycles done in fresh. We leave the leftover embryos in the culture medium to control their evolution and the biologists determine whether they can be frozen or not.
The freezing criteria are different from the criteria for evaluating the transfer of fresh embryos: they must meet very specific requirements because freezing and thawing are potentially aggressive processes for embryos.
If we freeze all the surplus embryos, the cancellation rates of a subsequent transfer after thawing would be very high, therefore we cannot freeze all the embryos left in the laboratory after the fresh transfer. Despite these requirements, there is a percentage of cryo-blotting after defrosting and re-adaptation period in culture medium of about 8%.
In what cases is oocyte vitrification indicated?
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To preserve fertility and delay the time of future motherhood.
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For surgical medical reasons or prior to chemo or radiotherapy
treatment affecting fertile ability
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For ethical-moral reasons when it is not desired to freeze embryos in an In Vitro Fertilization
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To increase the chances of pregnancy in cases of low ovarian response.
For patients with endometriosis who want to postpone their fertility or Surrogacy because of the effect that this disease can produce in the ovarian reserve.
Is there any relation between the freezing of embryos and the pregnancy of embryos transferred in fresh from the same cycle?
It is more difficult for embryos to develop in the laboratory than in the uterus of the mother. According to the studies carried out, there is no logical connection between the freezing of embryos and that of becoming pregnant after the transfer in fresh. So, it is not because we cannot freeze a part of the surplus embryos that you are not going to get pregnant or vice versa.
About the company
Dr Archana Dhawan is a reputed and one of the most celebrated Ivf Doctors in Delhi Ncr. She is the master of In Vitro Fertilization and assisted reproduction techniques.