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Follicle Output Rate

Meaning

Follicle Output Rate (FOR) is a clinical metric used in reproductive endocrinology to quantify the capacity of the ovary to produce mature follicles in response to controlled ovarian stimulation (COS) during assisted reproductive technology (ART). It specifically measures the number of pre-ovulatory follicles that develop per unit of exogenous gonadotropin administered, offering a more dynamic assessment of ovarian function than static markers like Anti-Müllerian Hormone (AMH). A high FOR indicates robust ovarian responsiveness, which is a strong prognostic factor for successful fertility outcomes.