By-and-large, women considering egg freezing fall into two main groups. Group one will
include women when they have a medical reason to consider egg freezing such as a family
history of early menopause usually on the mother’s side or when they’re diagnosed
with cancer and they’re concerned about the impact of chemotherapy on their egg reserve.
These patients are quite often fast tracked obviously in order to optimise the outcome.
Then you have the other group of patients that they fall within the category of what
we call social egg freezers and these are mainly women that are mid to late 30’s without
any partner who are concerned about the impact of the biological clock on their egg reserve
and of course egg quality.
You cannot compare the success rate of a frozen
embryo to a frozen egg. Obviously, when you have a frozen egg, the egg will have to go
through the process of egg warming so some of the egg may not survive. The egg will have
to be fertilised and the fertilised eggs have to obviously develop to a normal embryo. So
when you achieve an embryo from a frozen eggs, then the success rate between the embryo
that’s coming from the frozen egg versus a normally fertilised embryo will be almost
the same. The key in all this is egg survival. But if the egg survives, then the fertilised
egg will have the same, almost the same implantation potential as a fresh egg, as it were.
By-and-large, from the age of 35, fertility starts declining in women, and therefore,
for instance, if the upper age of egg donation in the UK is 35 and this is the reason why women
do get concerned about the impact of age on the egg quality and of course egg reserve.
The best age to freeze eggs in women who have no partner is between 35 and 40. However,
when women go beyond the age of 40, one has to be very careful in terms of alerting a
patient as to the importance of number 1, checking if they have good enough egg reserve
to benefit from egg freezing and number 2, they should be given the full information
about the impact of age on the quality of the egg because a big percentage of the egg
from the age of 40 onwards start having chromosomal abnormality that will have an impact on the
implantation potential of the embryo. So going back to what’s considered the ideal age,
obviously, it’s a very difficult area to define what is specific age, but by-and-large,
age 35-40 would be the optimum age.
The novel technique of vitrification, which
is a new way to freeze an egg, has been a game-changer in the field of assisted reproduction.
It has really opened new horizons for clinicians and for patients as well in the sense that
it would have been unthinkable a few years ago to have an egg bank. And now, we run a
large program of egg donation using frozen egg with excellent results. This enable us
to give time for matching, give the patient the right choice, et cetera, et cetera. In
addition, it also helps women where for instance they have a gynaecological condition such
as severe endometriosis where they have a significant disease in the ovaries and they
require surgery. These patients now can freeze their eggs prior to undergoing surgery in
order to optimise the outcome and of course it also enables patients with history of early
menopause or cancer to preserve their fertility.