What do you do if you opted to do chromosome testing on your embryos during IVF and they
all came back abnormal? Should you stop trying because further IVF attempts would be futile?
Or should you keep going? In the hopes that a future attempt may produce one or
more normal embryos. A new study has helped us to answer those questions. Stay tuned.
Most of the embryos that human beings produce are abnormal meaning that they do not have the
ability to produce a live birth. One of the most common abnormalities is when an
embryo does not have the correct number of chromosomes. Doctors refer to this as
aneuploidy. We have known for some time all women produce chromosomally abnormal
embryos but that older women produce more abnormal embryos than younger women.
During IVF, we have the ability to test embryos for aneuploidy. This is referred
to as preimplantation genetic testing or PGT for short. If you look at the percentage of abnormal
embryos produced by women of different ages, you will find, as expected, that the percentage
of abnormal embryos is higher when the eggs come from older women. For example, at my IVF center,
if we look at women under the age of 32, we find about 40% of the embryos we test are
abnormal. If we look at 38 to 40 year olds, we find that over 60% of the embryos are abnormal.
Where does that 60% number come from? Hundreds of couples produce thousands of
embryos that are tested. If we add up all of the embryos from all of those couples,
over 60% of them are abnormal. However, if we look at each individual couple,
we find some couples, on a given IVF cycle will have 0% abnormal embryos. Other couples
will have 100% abnormal. And still other couples have some percentage in between.
Is this just random chance? Or do some couples have a specific problem that makes
them more likely to produce all abnormal embryos? If that were true, then we would
counsel those patients that they should stop trying or use donor eggs or donor embryos.
Recently, doctors here in the USA, did a study. They looked at 538 couples who had all of their
embryos come back abnormal in their first IVF but who returned to do a second attempt. They
found that 56% of those couples had at least one normal embryo in their second attempt. Those
couples who did not find a normal embryo in their second attempt were on average 3 years older,
had less eggs, less embryos, a lower percentage of embryos that reached the blastocyst stage and
less embryos that could be tested. In fact, those couples who did have a normal embryo on
their 2nd attempt, had, on average, 3 embryos to test compared to one in those that didn’t.
Overall, women aged <37 years had more than an 80% chance of obtaining a normal embryo in
their second cycle. In contrast, only 25% of women aged >42 years were able to get
a normal embryo. However, in older women who produced at least three embryos for testing,
about half were able to produce a normal embryo.
Finally, when the researchers looked at the chance for a live birth,
couples that had an embryo for transfer in their second attempt, had a similar live birth
rate to those who were able to transfer a normal embryo in their first attempt.
Our Infertility TV Bottom Line is this. Don’t be too discouraged if all of the embryos in
your first IVF attempt were abnormal. There is still a pretty good chance for finding normal
embryos with a subsequent attempt especially if you are younger or have many embryos to test.