By now, most people are aware of this fact. If you have ovaries, the ability to get pregnant
using the eggs in your ovaries goes down as you get older. Judging by the messages that
we get here at InfertilityTV, people still have a lot of more specific questions. For example,
how fast does fertility decline? What age does it START to go down? Does it drop off suddenly
at a certain age? At what age am I no longer able to get pregnant? Stay tuned and I will explain
Two major factors determining your current fertility are how many eggs you have and their
quality. The eggs in your ovaries start forming while you are a fetus inside your mother’s uterus.
While you are a fetus, the number of eggs rapidly increases into the millions.
However, about three months before birth, all of the egg production
stops. From that point, the eggs start degenerating. As a result,
the older you get, the less eggs you have remaining. That is problem number one.
Time takes its toll on your eggs. The longer your eggs have been sitting in your ovaries,
the more their quality declines. Lower quality eggs are less likely to produce a pregnancy
and more likely to result in abnormal embryos which can miscarry. That is problem number two.
We know that this decline starts before you are born but when does it first become a problem?
In other words, when does it first start to become harder to get pregnant?
To answer this and other questions, we can look at three different types of studies
Study Number 1. General population numbers. We can look at a group of people and ask what
percentage of people are getting pregnant at various ages. This is relatively easy
to do but one problem with this type of study is that it cant take into account
who is TRYING to get pregnant. Let’s say we look at a group of people and determine
that there are less pregnancies in 45 year olds compared to 25 year olds. Is that because their
fertility is lower or because not as many 45 year olds are trying to get pregnant?
Study Number 2 IUI Studies - Older couples don’t have intercourse as often as younger couples.
This may lower their chance for pregnancy. To remove that variable, we can make sure
that everyone attempting pregnancy is being exposed to sperm at the time of ovulation
by looking at people having an intrauterine insemination. An even better group to study are
people using donor sperm. This reduces the chance that sperm problems are causing fertility issues
Study Number 3 IVF - In several countries, programs that perform IVF are required to
report pregnancies along with information about the patients including age. Since IVF is a common
treatment, we have very large databases that allow us to look at the impact of age
Okay. question #1. When does fertility start to decline? Fertility starts to decline
in the early twenties. When we look at various populations we see that the
chance for pregnancy starts to decline from age 20. It is a gradual and steady decline.
Some of this may be due to factors other than age. If we look at IUI pregnancy rates, we also
see a decline from the 20s but it appears to be more gradual. If we look at patients doing IVF,
pregnancy rates are pretty similar until the early 30s when they start to decline.
Question #2 - Is there an age when fertility drops suddenly? For our population that is not using
fertility treatment, there are two time points when fertility decreases a bit more rapidly.
At age 20 and age 35. The changes are pretty subtle, however. For IUI, it drops off more
rapidly after age 39 or 40. The same is true for IVF but again this is not a dramatic change
Question #3 Is there an age beyond which pregnancy using your own eggs
is no longer possible. That is hard to define so lets say the age at which
it is really really unlikely to be able to get pregnant. For this population, beyond age 45,
pregnancy was exceedingly rare. This was mostly true for IUI and IVF as well
Our InfertilityTV Bottom Line is this. If you have ovaries, the decline in fertility starts
in your early twenties. It declines fairly gradually so that by age 45, it is pretty rare
to be able to get pregnant on your own. If you are doing fertility treatment with IUI or IVF,
fertility is preserved a little better until maybe the late 20s or 30. It then starts to
decline more rapidly and it gets pretty difficult to get pregnant after age 45.