Inhibin B

What is inhibin B?

Inhibins are proteins thatre responsible for inhibiting the production of FSH. FSH, or folliculotropic hormone, is the substance responsible (along with other hormones) for regulating the menstrual cycle in women, stimulating the maturation of ova, and the production of sex hormones, both in women and men.

Inhibins are produced by the gonads (testes and ovaries), pituitary gland, and in pregnant women also by the placenta and corpus luteum. There are two subtypes of inhibins, namely inhibin A and inhibin B, and their levels in the blood rve depending on the phase of a woman's menstrual cycle – the highest levels of subtype B occur during the follicular phase.

Inhibin B – when to perform?

As this substance regulates the normal function of the ovaries– in terms of reproductive health and a woman's ability to become pregnant, abnormal levels– may be primarily associated with impaired conception.

Determining inhibin B levels in conjunction with testing anti-mullerian hormone is the most basic test for diagnosing female infertility, as both tests are an effective indicator of remaining ovarian reserve, that is, how many ovarian chambers will still be able to produce.

Inhibin B concentrations decline with a woman's age, reaching levels that are virtually indeterminate during menopause. Its values, therefore, are directly proportional to the number of remaining folliclesovarian follicles in the ovary.

Inhibin B – who should perform it?

Most commonly, inhibin B tests are performed in women during the diagnosis of reproductive health disorders. Symptoms of this type of disorder may include:

• difficulty getting pregnant
• irregular periods
• premature symptoms of menopause

This test is also performed in men when diagnosing fertility disorders and abnormalities in sex hormonemanagement.