Step 1: AMH directly tracks the number of small growing follicles, so it falls as the ovarian pool depletes. Fertility specialists use it to predict response to ovarian stimulation.
Step 2: A low value of AMH, specifically a reading under $1$ ng/mL, signals a poor remaining reserve and a likely weak response to fertility medication.
Step 3: The higher option ranges correspond to adequate or robust reserve rather than a depleted one, so they cannot represent low reserve. The level associated with low ovarian reserve is therefore less than 1.
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