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What is FSH ?
FSH is an acronym which
stands for Follicle Stimulating Hormone. Hormones are
chemicals in your body that are made in one place and
are used in another. As the name suggests, FSH is
responsible for stimulating the growth of the
egg-bearing follicles in your ovaries. It is one of the
two gonadotropins (so called because it stimulates the
gonads), the other being its partner, LH, which stands
for luteinising hormone. LH and FSH are secreted by the
pituitary gland, a small pea-shaped gland below the base
of your brain.
FSH levels vary during the
menstrual cycle and will peak prior to ovulation. This
is why the level of FSH in your blood is best measured
on Day 3 , and this is called the baseline ( basal)
level. FSH blood tests are generally performed on the
second or third day of your menstrual cycle, when they
provide the most accurate predictions of ovarian
reserve. The FSH is often measured along with the LH
level; and
estradiol .
Ovarian Reserve and
Follicle Stimulating Hormone
Your ovarian reserve refers to the number of
eggs that you have available for fertilization. A high
ovarian reserve usually indicates a good number of
viable eggs present in your ovaries. A low ovarian
reserve may indicate that you have fewer available eggs.
In order to test ovarian reserve, we measure your FSH
level , which correlates inversely with the number of
eggs that you have "on reserve" in your ovaries - your
ovarian reserve. Women with a poor ovarian reserve are
said to have reached their oopause. You can read more
about this at
www.drmalpani.com/oopause.htm. Women with poor
ovarian reserve will have high FSH levels. Some women
find it difficult to understand why FSH levels are high
in women with poor quality eggs. Intuitively, more is
better, so higher levels should mean better eggs,
shouldn't it ? As one patient asked me, " If FSH stands
for Follicle Stimulating Hormone, and I have high levels
of FSH, then doesn't that mean that I have the ability
to stimulate lots of follicles ? A high FSH should mean
that I should have lots of eggs ! "
Let’s look at the basic
biology. If the ovary has many eggs, the FSH in a
woman’s blood is low because the body doesn’t need to
produce much FSH to induce normal ovulation. However, if
the egg number is low, the body needs to work harder to
produce ovulation, so it increases the amount of FSH in
an effort to push the ovaries. A high FSH means the egg
number is reduced, sometimes to levels so low that
pregnancy is not possible.
What is a good level?
Well that depends on each individual lab. For most
centers, anything over 12 mIU/ml is considered poor .
In fact, some centers will not give fertility treatment
to those over 12 because the odds of pregnancy become
low.
Interpreting Levels of
Follicle Stimulating Hormone
A normal FSH level is
usually between 3 mIU/ml – 10 mIU/ml. Levels of more
than 12 mIU/ml are worrisome and suggest impaired
ovarian reserve. Levels of more than 25 confirm ovarian
failure and are found in menopausal women. FSH levels
can also be artificially raised by ovulation inducing
drugs such as clomiphene citrate ( clomid).
Low levels of FSH ( less
than 2 mIU/ml) are found in a condition called
hypogonadotropic hypogonadism. Women on birth control
pills as well as pregnant women also have low levels of
FSH.
The FSH level is best
interpreted in conjunction with your estradiol level.
Estradiol is one of the estrogens produced by the
ovaries. Estradiol levels above 75 pg/ml on Day 3 may
indicate a poor ovarian reserve. In some women , a high
baseline estradiol level ( because of poor ovarian
reserve) can artificially suppress the FSH level, so
that it appears to be normal, thus misleading the doctor
into believing that the ovarian reserve is normal. This
is why it’s a good idea to measure the estradiol level
when checking the FSH level on Day 3. If the estradiol
level is high, then even if the FSH is normal, we cannot
assume that ovarian reserve is normal.
A normal FSH and
estradiol level probably indicate that you have a good
ovarian reserve.
Elevated FSH levels may
suggest impaired ovarian reserve and may imply that you
consider begin treatment right away.
High levels of FSH may
indicate that you should consider using an egg donor.
Your eggs may not be fertile
Treatment for a high FSH level
Traditional teaching states that there is no treatment
for a high FSH level. Once the ovarian reserve is
depleted, the ovary cannot grow any new eggs. However,
if you have a borderline high FSH levels, there are many
alternative options you can explore to try to improve
your ovarian reserve.
These
include:
1.
yoga, to improve pelvic blood flow
2. acupuncture, to improve ovarian blood supply
3. DHEA ( dehydroepiandrosterone, 75 mg daily)
However, no clinical trials have been done to prove the
efficacy of these interventions, so you need to
understand that the results are unpredictable. However,
you might want to explore these alternatives, so you
have peace of mind you tried your best.
Monitor your own FSH levels
If you
live in the USA, the good news is that you can now
monitor your FSH levels yourself , to track your ovarian
reserve ; and see how it's responding to your
interventions.
You
can do this at
MyMedLab !

The
Clomiphene Challenge Test
Sometimes, doctor may
choose to perform a clomiphene challenge test. This is
an extension of the FSH test, however, it is more
sensitive. Think of it as a “stress-test” for your
ovaries !
This is the way to do the
test.
On Day 3 , you need to do
a blood test to measure your levels of FSH,LH,PRL and
TSH.
Take 100 mg clomiphene
citrate ( clomid) from Day 5 - Day 9.
Repeat the blood test for
FSH again on Day 10 .
If the Day 3 plus Day 10
FSH levels are more than 25, this suggests you have
ovarian failure, and that donor egg IVF would be your
best treatment option, if you are willing to consider
this.
If it is less than 25,
then consider IVF with your own eggs.
It is also necessary to
consider age when undergoing fertility treatment. Age is
an excellent predictor of both ovarian reserve and
conception rates. Women over the age of 43 have a
smaller chance of becoming pregnant than women under the
age of 43, no matter what their FSH levels. This means
that younger women with poor FSH levels may still want
to try using their own eggs before seeking a donor.
Other
tests for ovarian reserve
The other tests for
ovarian reserve include testing for
inhibin levels; and
AMH
levels.
Vaginal ultrasound
scanning is also useful for measuring the antral
follicle count.
FSH and LH levels in
patients with PCOD
We
often measure both FSH and LH levels. Normally, the
ratio is 1, which means the FSH level and LH level are
approximately the same. In patients with
polycystic
ovarian disease (PCOD), this ratio is reversed; and
patients with PCOD typically have a high LH level and a
normal FSH level. This is called a reversal of the
FSH:LH ratio; and in patients with PCOD it is 2 or
more.
FSH as a test versus FSH
as a medication
Measuring
the level of FSH in your blood is a very useful
diagnostic tool . FSH is also used as a medication to
help in superovulation during your IVF treatment. Brand
names include Follistim and Gonal-F.
Need help in
interpreting the results ?
Need help in
making sense of your lab results ? Please enter your lab
values and your clinical details in our Free Second
Opinion form at
www.drmalpani.com/malpaniform.htm and I’ll help you
interpret your results !
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