Normal Menstrual Parameters*

Frequency

≥ 24 to ≤ 38 days

Cycle length is defined as the number of days from first day of one menstrual period to first day of the next.

Regularity

≤ 7 to 9 days

Regularity is defined as variation of cycle frequency between the shortest and longest cycles.

Duration

≤ 8 days of bleeding per cycle

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Volume of bleeding

< 80 mL

Clinically, patient's description of bleeding as normal volume

Clinically, precise measurement bleeding volume is not feasible. Assessment of bleeding volume is based on the patient's description (light, normal, heavy).

Clinicians sometimes estimate by asking how many pads or tampons are saturated over time (heavy bleeding is likely if patients saturate a pad or tampon within 3 hours or less and/or if they pass blood clots larger than 1 inch [2.5 cm] in diameter).