What FSH level indicates low ovarian reserve?

The higher the FSH level, the lower the ovarian reserve. It is the opposite of AMH: the lower the AMH, the worse the ovarian reserve. Depending on the laboratory kit that we use to measure it, the higher the FSH is the worse the indicator will be to measure our ovarian reserve.

FSH at the beginning of the cycle may be helpful to detect low ovarian reserve – why? Because FSH is one of the molecules which stimulate the ovary and when the ovary produces estrogens, growing follicles produce estrogens, FSH drop down. So, when we receive high FSH, should mean that ovary does not working well and has low estrogens level and it means that woman has low ovarian reserve but if we compare FSH and AMH level, the problem that FSH is until the end of ovarian function will be more or less okay, probably slightly higher but more or less okay because even if we have only one follicle but this follicle produce some amount of estrogens, FSH will not be very high and when ovary will be totally empty, FSH will bumps rise dramatically.

No. High FSH doesn’t always mean low ovarian reserve but it is an indicator that things are shifting and changing and it will change every month. What it does mean when the follicle stimulating hormone is high – it means that it’s trying to sort of jump start the ovaries. It is a marker of low ovarian reserve depending on how high it is.

FSH stands for follicle stimulating hormone and it’s a hormone that is used when it’s released by a gland in the brain called the pituitary gland and it’s used to stimulate the ovary to release one egg each month and it works on a series of negative feedback. If your estrogen is low, the brain produces more FSH that makes you release an egg and then once the egg is growing and the estrogen levels rise, it gives negative feedback to the brain and the FSH level falls, goes down and this is what is done through with each menstrual cycle. Now women with Polycystic Ovarian Syndrome tend to have normal or sometimes slightly raised estrogen levels and because of that they tend to have either normal or low FSH levels. It’s one of the treats, if the women have raised estrogen levels, then they’ll have low FSH levels. If the estrogen levels are normal, then their FSH levels are normal and FSH is sometimes used as an indirect way of of measuring a woman’s ovarian reserve and if a woman has a low FSH which is typical in women with Polycystic Ovarian Syndrome, it implies that they have lots of eggs, there are many eggs there and so it’s an indirect way of estimating a woman’s ovarian reserve. If a woman’s FSH is high and what we consider a woman to have a good ovarian reserve if our FSH level is less than nine. We consider her to have polycystic ovaries, if FSH is less than three because that shows that she has lots and lots of eggs and we consider her to have a low ovarian reserve if her FSH is above nine. With FSH levels over 14, we tend to think of a woman as being perimenopausal and if it’s over 30, sometimes that’s diagnostic of being in the menopause.

Usually the other way around – FSH does not give us indication of low ovarian reserve. Usually we use FSH and we see extreme measures of FSH not more than 10, even more than 15 or 20 when women go through a perimenopausal period. What happens is as the ovarian reserve drops, the egg quality can become worse with the advanced female age, what happens is poor egg quality is to lower estrogen levels, so no good quality eggs that we have low estrogen levels. This low estrogen levels will not have negative feedback to FSH, what will happen that way the FSH will remain high, so basically high FSH perhaps means not good egg quality or comes from the egg is not of good quality but doesn’t mean that there is indicator of low ovarian reserve and cannot be used like that because of the fluctuations that you can see. In one year time doesn’t mean all the eggs that you will release will be of poor quality. If at some point we measure the FSH, the baseline FSH and it is high, it doesn’t mean this is consistent unless we have the irregularity of the cycles like the second indicator that perhaps we run through the perimenopausal period.