| Table 1. Clinical dimensions of menstruation and menstrual cycle, and description of normal limits | ||
| Denomination | References | |
| Menstruation and menstrual cycle | ||
| Monthly frequency (days) | Frequent | <24 |
| Normal | 24–38 | |
| Infrequent | >38 | |
| Regularity of menstruation Variation in 12 months (days) | ||
| Absent | ||
| Regular | 2–20 days | |
| Irregular | >20 days | |
| Duration of flow (days) | Prolonged | >8.0 |
| Normal | 4.5–8.0 | |
| Shortened | <4.5 | |
| Volume of monthly blood loss (mL) | Increased | >80 |
| Normal | 5–80 | |
| Light | <5 | |