High FSH Info

Here are some additional facts about FSH:

• FSH varies throughout a woman’s cycle. For fertility testing, FSH is typically tested somewhere on days 2 through 5. This is because the early fertility research used readings from days 2 through 5 for consistency. If you have an FSH reading from other days of your cycle, your doctor will need to interpret it for you. For purposes of this document, FSH refers to a reading taken from days 2 through 5. Note that some RE’s only do FSH testing on particular cycle days – e.g., day 3.

• FSH fluctuates from cycle to cycle. In young women, the FSH is nearly always low and the fluctuation is minimal. As a woman ages, the fluctuation becomes greater and the maximum readings get higher and higher until finally a woman enters perimenopause and, subsequently, menopause. Most RE’s believe (and there is some evidence in clinical studies to support this) that a woman’s ovarian reserve is only as good as her worst (highest) FSH reading. In other words, if a woman has an FSH of 25 one month and 5 the next month, then her ovarian reserve did not improve during the course of the month – diminished ovarian reserve is indicated by the reading of 25. Some RE’s, however, take this rule with a grain of salt and depending on the other indicators of ovarian reserve may accept a woman for an IUI or IVF cycle if a woman’s FSH is below the cutoff even if she has had other readings above the cutoff. Note that after a woman enters menopause, the FSH is elevated and stays elevated. So as long as the FSH is fluctuating, the odds of conception are higher than if it remains elevated.

• Age is a more important predictor of fertility than FSH. The most important factor that RE’s use to determine whether a woman has DOR is age. Age is considered a much more important factor than FSH, although most clinics have both age and FSH cutoffs. High FSH is viewed as less of an obstacle in younger women.

• FSH levels vary across laboratories. FSH is a complex hormone to measure and there is a lot of variation in its measurement across different laboratories. In the same cycle, a woman could go to three different laboratories and get three different FSH readings. This is important to keep in mind when discussing your case with a new RE. It’s best to retest the FSH in the new RE’s lab so that there is no confusion.