FSH, or Follicle Stimulating Hormone, is a hormone that is produced and released by the pituitary gland in the brain and it stimulates the ovaries to develop follicles, ripen the eggs and eventually release the eggs. FSH oscillates from one cycle to another but in young women with good ovarian function, FSH level is normally low and the fluctuation is minimal.
As a woman ages, her ovaries produce less oestrogen and the brain tries to jump-start the process by sending more FSH into the bloodstream. The higher level of FSH prompts the ovaries to recruit more than the dozen follicles, typically developed, to produce oestrogen for the next cycle.
During the perimenopause period, while there may be regular cycles, the follicles’ response to FSH becomes unpredictable and oestrogen levels can be unusually high and low with a wide variety of symptoms.
FSH fluctuation becomes greater and the maximum reading gets higher and remains high until finally the woman enters menopause at an average age of 51 following 10 to 15 years in the transition period.
FSH is often used as a gauge of Ovarian Reserve
High FSH is an extremely frustrating diagnosisA baseline FSH blood test on day 2 or 3 of the menstrual cycle is expected to be below 10 iu/l (international unit) in women with reproductive potential.
- In general, FSH level under 6 is excellent, 6-9 is good, 9-10 fair, 10-13 indicates diminished ovarian reserve. 20+ indicates that the egg pool is pretty much exhausted.
- Most IVF treatment involves giving injections of the hormone FSH to encourage the ovaries to produce more than the one egg. If your pituitary gland produces already high amount of FSH, your ovaries are unlikely to respond to fertility drugs.
The preparations of FSH most widely used in the UK are Gonal-F and Puregon. Menogon, Menopur and Merional also contain LH (luteinising hormone).
- FSH levels of 10-12 iu/l are considered borderline for IVF treatment and if the FSH is much above 10 iu/l, then attempts to stimulate the ovaries may be a complete failure.
If it is above 15 iu/l, they are very poor indeed. It is virtually never worth considering IVF if the level is over 20.
- In PCOS testing, the LH:FSH ratio may be used in the diagnosis. The ratio is usually close to 1:1, but if the LH is higher, it is one possible indication of PCOS.
- When a woman’s FSH blood level is consistently elevated to 30 mIU/mL or higher, and she has not had a menstrual period for a year, it is generally accepted that she has reached menopause.
- FSH matters in men as well. If a man’s FSH levels are high, the testes may have stopped producing sperm and if very raised, there may be a total testicular failure.
Finding FSH levels in the menopausal range is very common among our patients and it is a difficult issue to deal with as high FSH indicates a poor ovarian reserve with the number of eggs left in the ovaries declining and the woman is undergoing menopausal transition. As a consequence, the woman becomes progressively less fertile.
Many women with high FSH levels are told that there is nothing that can be done to help with this. They cannot even embark on IVF or IUI until their FSH drops to 11 or 12, the usual cut-off line, as they are more likely to be poor responders to fertility drugs.
Hormone Replacement Therapy using contraceptive pills or oestrogen replacement therapy can artificially suppress FSH and relieve symptoms but the use of an exogenous synthetic hormone can cause suppression of the natural hypothalamus-pituitary-ovarian axis feedback communication and does not necessarily improve a poor ovarian reserve or increase the chance of conception. Fertility drugs or hormonal replacement treatment do not address the cause for the failure of the ovaries.
Women with high FSH levels are often advised to consider IVF with donor eggs. However, Most women with high FSH prefer a treatment that will restore their ovaries and hormonal system to fully functional health and will hopefully enable them to conceive with their own eggs and have their own genetic children.
Degree of Oestrogen deficiency
Symptoms of oestrogen deficiency often develop with high FSH in many, but not all, patients. The symptoms include night sweats; insomnia; headaches; restlessness; lethargy; short menstrual cycle with scanty bleeding; irregular periods; amenorrhea; early ovulation; anovulation; lack of cervical mucus; infertility. These symptoms may appear suddenly over a couple of months, or gradually over several years. My article on Premature Ovarian Failure (POF) is here.
Seeing my female patients mostly in their late 30s and early 40s, when hormone regulation or steroid decline becomes a problem compounded with subtle metabolic changes, not only fertility issues, I often observe signs and symptoms of whole body transitions.
From the mid 30s, it is not only circulating major hormones such as growth hormone, insulin, thyroid hormone, cortisol and sex steroids that undergo changes but the functions and sensitivities of many glands and tissue receptors decline. Changes in sex steroid levels during perimenopause are compounded by a lowered metabolic state with numerous repercussions in lowered cellular activities, adrenal gland compensation with stress response pathology, chronic inflammation, autoimmunity and coagulopathy (clotting disorders).
The cell’s environment, the signals and substances and energy it receives is complex and its manifestations can be across the spectrum. When it comes to ovarian depletion, we see it as a continuum of impaired ovarian function rather than a dichotomous state. Everyone’s transition has different shades, therefore the assessment and the treatment should be individualized and multi-faceted.