By measuring a woman's baseline FSH on day 3 of the cycle (we do it on day 2, 3, or 4), we get an indication as to whether she has normal “ovarian reserve”. We are looking at how hard her body needs to “step on the gas” early in the menstrual cycle to get a follicle growing.
FSH is best tested on day 3 of a woman's menstrual cycle, but could be done between days 2 and 4. At-home FSH tests use a woman's urine (at the doctor's office, we analyze FSH levels in her blood) and provide the range of FSH, either normal or elevated. If the test is elevated, fertility is most likely decreased.
Estradiol, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) all need to be tested on day 3 of the menstrual cycle to get the most clinically meaningful results.
FSH, LH and oestradiol should be checked early in the menstrual cycle (day two – six, where day one is the first day of menstruation). Elevated FSH suggests reduced ovarian reserve and the possibility of impending premature ovarian failure.
The FSH test
The ideal time to sample blood for FSH levels is on day 3 of a cycle although day 2-5 will probably suffice. Any testing outside of these days is irrelevant. When used as a screening test for ovarian reserve, levels of estradiol should also be measured.
LH should be measured on day 2-5 of your cycle with a blood test. Progesterone – prepares the lining of the womb (endometrium) for the embryo (baby) to implant. It goes up in the second half of your cycle after you ovulate, so is measured to check for ovulation (that you are releasing an egg every month).
There is no value in measuring the hormones FSH, LH and E2 at the same time as a Day 21 progesterone because their interpretation is not of any value if the progesterone is raised, as it should be in the mid-luteal phase.
The follicular phase of the menstrual cycle is the stage between the first day of menstruation and ovulation. During this phase, FSH stimulates several follicles inside the ovaries, which causes them to start maturing. FSH levels are highest during the first week of this phase.
Conclusions: The initial FSH rise in the cycle occurs consistently 4 days before menses, is related to a drop in estrogen levels, and is not affected by reproductive ageing.
Also, as mentioned earlier, FSH is elevated during the early follicular phase and then begins to decline until ovulation. In contrast, LH is low during the early follicular phase and begins to rise by the mid-follicular phase due to the positive feedback from the rising estrogen levels.
Why do we measure the FSH level on day 3? By measuring a woman's baseline FSH on day 3 of the cycle (we do it on day 2, 3, or 4), we get an indication as to whether she has normal “ovarian reserve”. We are looking at how hard her body needs to “step on the gas” early in the menstrual cycle to get a follicle growing.
At InVia Fertility Specialists, we like the FSH level to be < 10 mIU/mL. A value between 10 and 15 mIU/mL signifies diminished ovarian reserve. A value > 15 mIU/mL (and definitely > 20 mIU/mL) signifies severely diminished ovarian reserve and a pregnancy rate with IVF of < 1%.
In women with regular menstrual cycles, FSH levels tend to range from 1.4-9.9 mIU/mL during the first half of the menstrual cycle before rising up to 17.2 mIU/mL during ovulation.
Our results indicate that in the normal cycle, the onset of FSH rise occurs consistently 4 days before menses, is directly related with a drop in estrogens levels, and is not affected by reproductive ageing.
Conditions Related to High FSH
If this is the case, you will have other signs of menopause as well, like missing your period and low levels of estrogen. These symptoms may be more severe than in women in natural menopause, and is considered atypical as it begins much earlier.
FSH levels are lowest at the beginning of the menstrual cycle and then go up, helping a follicle to grow and the egg to mature. At this time, the follicles release estradiol. These higher levels of estradiol tell the pituitary gland to produce less FSH.
In women, FSH helps control the menstrual cycle and stimulates the growth of eggs in the ovaries. FSH levels in women change throughout the menstrual cycle, with the highest levels happening just before an egg is released by the ovary.
What does having high FSH levels mean? An elevated FSH indicates diminished ovarian reserve. Diminished ovarian reserve is associated with a reduced number of follicles or eggs, often of questionable quality.
Blood tests for women
On day 2 FSH (Follicle Stimulating Hormone) levels will be measured. This helps us check how responsive your ovaries are. You may also have a blood test for AMH (Anti-Mullerian Hormone) for the same purpose. Antibodies to rubella (German measles).
15-25 mUI/ml: FSH levels are elevated and this could be a sign your ovaries are struggling to grow an egg each cycle. At this point you may be experiencing perimenopausal symptoms, even though you are still menstruating and ovulating. As long as you are ovulating, it is still possible to conceive.
Serum FSH levels are known to fluctuate during different phases of menstrual cycle in premenopausal women, and increase considerably after the menopause as a result of ovarian function cessation.
FSH causes ovarian follicles to enlarge and produce estrogen. Over time, fewer and fewer follicles remain to be stimulated and thus estrogen levels decline as a woman ages. This decline in estrogen leads to an increase in FSH as there is not enough estrogen being produced to "turn off" the brain's production of FSH.