What is high FSH?
FSH is a hormone produced by the pituitary gland that is controlled by hormones produced by eggs in the ovary (primarily inhibin and estradiol). Specifically the more eggs there are in the ovary the higher estrogen and inhibin levels, the lower FSH will be. A low FSH is therefore indicative of more eggs in the ovary, a high FSH is indicative of low numbers, low ovarian reserve. FSH naturally increases as a woman ages. FSH levels in menopause are very high typically above 40 IU. If FSH is elevated in a younger patient this is known as premature ovarian aging.
It has been shown that high FSH, i.e., low ovarian reserve also relates to the quality of eggs. A young patient with an elevated FSH level is likely not only to get fewer eggs than her aged appropriate cohorts, but also eggs of lesser quality. At the Florida Institute for Reproductive Medicine these patients are aggressively treated, moving quickly to IVF. We have seen very encouraging pregnancy rates with the addition of growth hormone therapy in such patients.
IVF success related to FSH level.
In general, success of IVF is dependent on the number and quality of eggs obtained, assuming there is no significant uterine factor and there are viable sperm. Low to normal FSH levels again indicate normal or high ovarian reserve, i.e, a greater probability of obtaining a large number of good quality eggs hence embryos. Other estimates of ovarian reserve include anti-mullerian hormone level (AMH), as well as the antral follicle count (AFC), the number of small follicles at the beginning of the menstrual cycle determined by vaginal ultrasonography.
FSH versus AMH versus Antral Follicle Count
FSH is probably the most widely used measure of ovarian reserve and has been used since the early 90s. Most infertility specialists are very comfortable interpreting FSH levels. One of the drawbacks to FSH is that it has to be checked early in the menstrual cycle, ideally on day three. In addition an estradiol level should be drawn to properly interpret FSH levels. More recently anti-mullerian hormone levels have been shown to be a more accurate predictor of ovarian reserve especially when interpreted along with antral follicle count. An AMH level can be drawn anytime in the menstrual cycle, even if a patient is on a birth control pill. At the Florida Institute for Reproductive Medicine we rely primarily on anti-mullerian hormone levels and antral follicle count to assess ovarian reserve.
Should women with elevated FSH levels be offered infertility treatment?
Many fertility centers as well as many insurance companies will ask for ovarian reserve testing to determine whether a patient will be offered treatment. At the Florida Institute for Reproductive Medicine as long as a patient does not have a menopausal FSH or AMH level, is age 47 or below – she will be offered treatment. We believe what is most important is proper informed consent, allowing the patient to make the decision whether to treat. If a patient’s ovarian reserve is very poor it will be explained to her that certainly donor egg in vitro fertilization is going to provide the greatest chance for pregnancy. There are many patients who need to try with their own eggs before donor egg is an option.
FSH, Anti-Mullerian Hormone level, Antral Follicle Count – guesstimates of ovarian reserve.
The gold standard in terms of determining ovarian reserve is to stimulate the patient with high doses of gonadotropin for 6-7 days with follow up ultrasound to assess follicle development. Unfortunately gonadotropin medications are expensive and frequently not covered by insurance, if a patient feels very strongly about trying to conceive with her own eggs this is offered at the Florida Institute for Reproductive Medicine. Depending on response a cycle can be continued to egg retrieval, i.e., IVF or couple can do timed intercourse or insemination.