While a handful of hormones are responsible for fertility, follicle-stimulating hormone (FSH) is the best indicator of the testes’ ability to produce sperm, as it is responsible for jumpstarting the chain of events that leads to sperm production. FSH also maintains sperm until they are ready to be released, making it a key hormone for fertility.
Testing for FSH
If you are found to have low sperm counts during your initial fertility evaluation, your Inovi fertility specialist will order blood tests to measure FSH levels along with other important hormones like Testosterone (T), Luteinizing Hormone (LH), Thyroid Stimulating Hormone (TSH) & Thyroid Hormone (T4), and Prolactin. The levels of these hormones will help create a clearer picture of your fertility.
The normal range for FSH varies widely between labs, but studies have shown that FSH levels greater than >7.0 IU/L correspond with an increased chance of an abnormal semen analyses. For this reason, measuring FSH is especially important if your semen analysis shows a low sperm count.
It is possible that ejaculatory problems or other anatomical issues are the cause of low or absent sperm rather than endocrine function, in which case FSH, LH, TSH/T4, Testosterone and Prolactin may be normal.
Causes of High FSH Levels
High FSH levels in men typically mean that the testes are not functioning properly. When this is the case, the pituitary gland that regulates hormones in your brain goes into overdrive, producing additional FSH to support sperm production.
High FSH levels due to testicular failure may be caused by:
- Chromosome abnormalities
- Undescended testicles
- Chemotherapy or radiation
- Testicular injuries
- Testicular damage from disease (cancer, alcoholism)
- Genetic problems
- Advancing age
- Hormonal disorders
- Certain medications
- HIV/AIDS
- Type 2 diabetes
In the case of complete testicular failure, blood test results will show high FSH levels and high LH with normal or low Testosterone.
Causes of Low FSH Levels
The most common cause of low FSH levels in men is the use of testosterone or steroids. These tell the brain that your body is producing enough Testosterone, causing it to shut down its natural production and, consequently, your body stops producing FSH. This chain reaction then shuts down sperm production, causing infertility. Low FSH levels are more pronounced with longer testosterone or steroid use.
The next most common cause of low FSH is a pituitary gland malfunction that could be caused by:
- Genetic conditions
- Head trauma
- Medications
- Auto-immune disorders
- Pituitary tumors
- Elevated Prolactin
Treatment for High & Low FSH in Men
Abnormal FSH levels often require additional testing to determine the cause before treatment can be implemented. In some cases the cause may be known in advance, such as genetic conditions, diseases, medications or history of treatment for cancer. If a hormone imbalance, such as low testosterone, is the cause of abnormal FSH levels, then your Inovi fertility specialist will refer you to a urologist that specializes in male fertility to provide treatment for your condition and to improve your chances to conceive. In cases where the sperm count cannot be increased with medication or surgery (e.g. early testicular failure) fertility treatments such as In Vitro Fertilization (IVF) or use of donor sperm may still be an option that allows you to achieve pregnancy.