Inhibin B is another hormone produced by the ovaries that
decreases as women approach menopause. Inhibin B testing can be used alongside
AMH to get a more comprehensive assessment of ovarian function and reserve.
What is Inhibin B?
Inhibin B is a hormone produced by the granulosa cells in
the ovarian follicles.
Levels of Inhibin B decline as women age and approach
menopause.
How is the Inhibin B test used for menopause?
·
The Inhibin B test can provide information about
a woman's ovarian reserve and help assess her proximity to menopause.
·
Declining Inhibin B levels are often an early
indicator of diminishing ovarian function.
·
Inhibin B testing is sometimes used along with
other tests like AMH and FSH to get a more comprehensive evaluation of ovarian
aging.
What do the Inhibin B test results mean?
·
Normal pre-menopausal Inhibin B levels are
typically between 45-400 pg/mL.
·
Levels below 45 pg/mL are generally considered
indicative of diminished ovarian reserve and impending menopause.
·
Very low Inhibin B levels (under 10 pg/mL) are
often seen in women who have reached menopause.
How is the Inhibin B test done?
·
The Inhibin B test is a simple blood test that
can be done at any time during the menstrual cycle.
·
The blood sample is analyzed in a lab to
determine the Inhibin B concentration.
Limitations of the Inhibin B test:
·
Inhibin B levels can fluctuate throughout the
menstrual cycle, so timing of the test is important.
·
Inhibin B is not as predictive of the timing of
menopause as AMH for some women.
·
Other factors like medications, chemotherapy,
and certain medical conditions can also affect Inhibin B levels.
Comparing Inhibin B to Other Menopause Tests:
·
Inhibin B complements tests like AMH and FSH to
provide a more complete picture of ovarian function.
·
AMH is considered a better predictor of the
timing of menopause onset.
·
However, Inhibin B can sometimes detect ovarian
aging earlier than AMH.
·
FSH levels rise as menopause approaches, but
Inhibin B starts declining sooner.
Clinical Utility of Inhibin B Testing:
·
Inhibin B is particularly useful for evaluating
ovarian reserve in younger women.
·
It can help identify women at risk of premature
ovarian insufficiency.
·
Monitoring Inhibin B over time can track the
progression towards menopause.
·
Inhibin B is also used to assess ovarian
function in women with polycystic ovary syndrome (PCOS).
Clinical use examples
Examples of how Inhibin B testing is used in the clinical
management of women's health conditions:
1.
Assessing Ovarian Reserve:
a. Inhibin
B testing is commonly used to evaluate a woman's ovarian reserve, particularly
in the context of infertility or family planning.
b. Lower
Inhibin B levels can indicate decreased ovarian function and a shorter
remaining reproductive lifespan.
c. This
information helps guide decisions about fertility treatments, egg freezing, or
the timing of family planning.
2.
Diagnosing Premature Ovarian Insufficiency
(POI):
a. Inhibin
B is used to help diagnose premature ovarian insufficiency, also known as
premature menopause.
b. Women
with POI have elevated FSH and low Inhibin B levels before the age of 40.
c. Inhibin
B testing can identify POI earlier than just relying on FSH and other hormone
levels.
3.
Monitoring Ovarian Function in PCOS:
a. Inhibin
B levels are often assessed in women with polycystic ovary syndrome (PCOS).
b. In
PCOS, Inhibin B levels may be higher than normal due to the increased number of
ovarian follicles.
c. Monitoring
Inhibin B over time can provide insights into ovarian function and help guide
PCOS management.
4.
Evaluating Ovarian Function After Cancer
Treatment:
a. Inhibin
B testing is used to assess ovarian reserve and function in women who have
undergone chemotherapy or radiation therapy for cancer.
b. Lower
Inhibin B levels may indicate ovarian damage and increased risk of premature
menopause.
c. This
information helps guide fertility preservation options and long-term care.
5.
Investigating Menstrual Irregularities:
a. Inhibin
B can be measured in the evaluation of irregular menstrual cycles or amenorrhea
(absence of periods).
b. Abnormal
Inhibin B levels, along with other hormones, can point to the underlying cause,
such as hypothalamic amenorrhea or perimenopause.
Overall, the Inhibin B test is a helpful tool that, when
used together with other menopause tests and clinical evaluation, can provide
valuable insights into a woman's ovarian function and proximity to menopause.
But it should not be solely relied upon for making a diagnosis.
