Follicle Stimulating Hormone, or FSH, is a hormone secreted by the pituitary gland in the brain that stimulates the growth of the egg follicle every month as part of the menstrual cycle . Women with PCOS often do not ovulate every month due to low FSH levels.
If your healthcare provider suspects you may have PCOS, they will order a blood test for FSH along with other hormones before diagnosis. Older women tend to have elevated levels of FSH in their blood, indicating ovarian maturation. This is because the ovary requires more hormones to activate and stimulate the egg follicle.
FSH levels during your cycle
FSH levels change throughout the menstrual cycle. Healthcare professionals will often check your FSH levels on day 3 of your cycle. Their reference levels are considered. FSH is part of a complex hormone that includes luteinizing hormone (LH), estradiol, and gonadotropin-releasing hormone (GnRH). FSH stimulates the growth of an immature follicle. Once it has grown, it releases estradiol, which indicates the release of GnRH and LH, which induces ovulation.
Before ovulation, FSH levels peak, indicating that the ovary will release an egg. Once ovulation occurs, levels will return to or slightly below baseline.
Normal baseline FSH levels in menstruating women are between 4.7 and 21.5 mIU / ml.
Some medications, such as birth control pills, clomiphene, digitalis, and levodopa, can change the test results. Your healthcare provider will recommend that you stop taking these medications before your FSH test. In the case of hormonal contraception, it should be stopped for at least four weeks before testing.
FSH and pregnancy planning
Since women with PCOS have low FSH levels and therefore do not ovulate regularly, she generally seeks out a reproductive specialist or reproductive endocrinologist to help her during pregnancy when the time is right.
These specialists, known as reproductive endocrinologists, will use a variety of medications and hormones to stimulate ovulation and stimulate the secretion of sex hormones in women with fertility problems. FSH is one of the hormones that you use regularly.
Reproductive endocrinologists will use a synthetic form of FSH (such as Gonal-f, Follistim, or Bravelle) to stimulate the ovaries to produce egg follicles for intrauterine insemination (IUI) or in vitro fertilization (IVF) .
Many women often want to hear that injections are necessary to stimulate ovulation. While injections can be inconvenient, it is important not to lose sight of the big picture: delivery.
FSH and ovarian reserve
In women who want to become pregnant at a later age, FSH levels are used to check ovarian reserve (the number and quality of eggs left behind by the woman). Your healthcare provider will do a blood test on the third day of your menstrual cycle. Results are usually available within 24 hours, depending on the lab.
A fertility specialist can use lab tests to assess your chance of getting pregnant, even if you are nearing menopause .
Initial FSH levels will increase as women enter perimenopause , indicating a decrease in the number of oocytes (eggs). Perimenopause lasts an average of four years and ends when a woman has not had a period for 12 months.
At this point menopause begins. FSH levels steadily increase during menopause to 30 mIU / ml and higher.