FSH, or follicle stimulating hormone, is one of the most important hormones in a woman's reproductive health. Follicle stimulating hormone, as the name suggests, stimulates the female ovaries to produce a mature egg for fertilization. Measuring a woman's FSH levels can give doctors an indication of the quality of eggs a woman has as well as her chances of having a successful pregnancy.
Women are born with a set number of eggs. As they age the number and quality of eggs decreases. One of the ways doctors check to see the quality of eggs that a mom has is by testing her FSH level. Basically FSH goes up in response to a negative feedback loop. Meaning as a woman's eggs start to diminish in quality or number, her body will in turn make more FSH to compensate. The egg itself communicates with the women's body to tell it to make certain hormones. So testing a woman's hormone levels can help determine the quantity and quality of eggs a woman has.
In order for testing to be accurate, FSH levels must be checked during a certain time frame. Most doctors test around cycle day three. Sometimes a test may come back normal one month and abnormal another month but a rise in FSH levels is indicative of a problem. This is not to say that a woman can never get pregnant with a high FSH level. We have all heard of someone who was told that she could not get pregnant and some how beat the odds. But from a medical standpoint, abnormally high FSH levels make infertility increasingly difficult to treat.
One of the ways that doctors treat infertility is to use artificial means to increase FSH levels to force the body to ovulate or produce more eggs. If a woman is already producing a high level of FSH then artificially increasing her FSH levels will not likely improve her chances of getting pregnant. Also having high FSH levels can mean that the quality of eggs produced is diminished, not just the number of eggs being produced. So that even if a woman does become pregnant her chances of having a successful pregnancy are also affected.
There are options for women with high FSH levels but they may involve using donor eggs. If you are concerned about your fertility please talk to your doctor for medical advice.