IVF why do some people get more eggs than others?
You just had your egg retrieval. You got 8 eggs and are pretty happy with yourself.
Then you go online and you see somebody else got 18 eggs and another got 28
eggs. Why do some people get more eggs than others? Stay tuned and I will explain
The number of eggs that you can get during an IVF egg retrieval depends on four factors 1)
The number of eggs remaining in your ovaries 2) The ability of your ovaries to respond to
fertility medications 3) The dose of medication used to stimulate your ovaries and 4) your anatomy
The number of eggs remaining in the ovaries is called ovarian reserve. The eggs in the
ovaries are formed before birth. During the time that a fetus is developing, the number
of eggs in the ovaries are increasing. But about 3 months before birth, all of the egg production
stops. Then the eggs start degenerating. This causes the number of eggs remaining to drop.
As a result, as women get older, the number of eggs remaining in the ovaries gets
lower and lower. As a general, older women will have lower ovarian reserve compared to younger
women. Sometimes, however, younger women can also have a low reserve.
Women with low reserve do not get as many eggs during IVF, on average,
as women with a normal reserve. Therefore, Measuring ovarian reserve is an extremely
important group of tests to have before doing IVF. I talk about that extensively in this video.
People with a high reserve can get a larger number of eggs during IVF. One example of a
group of people with a high ovarian reserve are people with PCOS. People
with PCOS have more eggs and follicles than other people of a similar age. As a result,
they respond better to fertility medications and therefore produce a higher number of eggs.
Some people with a normal reserve of eggs, may still not respond well to the medications we use
for IVF. To understand why this could happen, we need to understand how fertility medications work.
Each egg in the ovary is surrounded by a group of cells called granulosa cells. The
granulosa cells have protein receptors on their surface. Hormones such as FSH, which stands for
Follicle Stimulating Hormone, will attach to the receptor. After the FSH attaches, a signal
is sent into the cell. These signals tell the cell to do a variety of things. In some people,
these hormone receptors may not work correctly. One possible cause of a malfunctioning receptor
are mutations in the gene that makes the receptor. Scientists have discovered a
small fraction of the mutations which cause these receptors to not work well but there are likely
hundreds of others. Some of these mutations may cause only a mild problem with the receptor.
Some may be more severe. If the receptor does not work correctly, then the ovaries may not respond
to the medications as well and those people may not get as many eggs during the egg retrieval
As of right now, we don’t ha ve an easy way to identify if a person is going to have this problem
In general, there is a relationship between how much medication is given
and how many eggs are retrieved but this isn't true 100% of the time.
For example, in women with poor reserve or in those who have resistant ovaries,
increasing the dose of medications may not increase the number of eggs
Even if the ovaries respond to fertility medications, the doctor still has to be able
to get them out. A person who has ovaries that are difficult to access may end up with some
eggs left behind in the ovary. This can happen in people who have scar tissue which is pulling
their ovaries into an inaccessible position or masses like fibroids might get in the way.
Being overweight can also make it more difficult to get to the ovaries to retrieve eggs.
One final point, there is a large amount of variation in the ovaries from one month
to the next. It is possible to get more eggs on one attempt and less on another.
Watch this video for more information about that
Our InfertilityTV Bottom line is this. There are a number of variables that can
result in a difference in your ability to get eggs during IVF. Some of these
you might know about ahead of time but some you may not.