Follicle-stimulating hormone, known as FSH, is produced in the pituitary gland. It is intimately connected with your reproductive system. In women, low FSH can decrease fertility and interfere with your menstrual cycle by not signalling for your ovaries to stimulate follicles and release eggs. Men with low FSH may not produce as much sperm. Low FSH levels are a common symptom of the following conditions: hypopituitarism, polycystic ovarian syndrome (PCOS), Turner syndrome and Klinefelter syndrome.
Individuals with low FSH may recognise some of these symptoms. Low FSH is often associated with infertility both for men and women. For women, FSH signals ovulation and the production of oestrogen, which regulates the menstrual cycle. Low FSH can keep women from ovulating and may cause excessive body hair, weight gain and deepening of the voice. For men, FSH controls the production of sperm, reducing fertility when FSH is low. Men with low FSH may experience slight breast growth, less body hair than normal and tall height.
Hypopituitarism is caused by a disorder of the pituitary gland that decreases its function and prevents it from excreting the hormones your body needs, including FSH. The pituitary gland is in the brain, and anything that can damage the brain can potentially damage this gland, including trauma to the head, treatments for brain cancer, stroke and diseases of the brain. Treatment for hypopituitarism involves hormone therapy for the hormones that it no longer produces in great enough quantity.
Polycystic Ovarian Syndrome (PCOS)
PCOS occurs when the ovaries develop cysts, generally from underdeveloped follicles that cannot mature and release their eggs. These cysts interfere with the hormone cycles that cause menstruation, which can lead to low FSH. If you have PCOS, you may experience irregular menstruation, growth and darkening of body hair and weight gain. PCOS can lead to infertility. This condition is treated with birth control pills and other drugs that regulate your menstrual cycle.
Our sex characteristics are, in part, determined by our genetic chromosome make-up. Men have XY chromosomes and women have XX chromosomes. Turner syndrome is caused by a female lacking one or part of one X chromosome. Occurring in one of 2000 births, this condition is fairly common and cannot be prevented. Many people with Turner syndrome will experience ovarian failure, which, among other symptoms, can cause low FSH levels. Individuals with Turner syndrome may be treated with growth hormones, and women who wish to give birth can consider a donor egg.
Klinefelter syndrome is another chromosomal condition in which a male has an extra X chromosome. Male infertility is a common symptom of Klinefelter syndrome. As FSH is responsible for the production of sperm in men, it is part of the diagnosis for this condition. Testosterone treatments can help increase fertility and encourage male secondary sex characteristic for individuals with Klinefelter syndrome.