how your period works
the cycle that runs your body every month
the 4 phases
Each phase brings hormonal shifts that affect your energy, mood, and body.
tap any phase to learn more
what's normal
"Normal" covers a surprisingly wide range. Here's what the research shows.
Cycle Length
21–35 days (average is 28)
Period Length
2–7 days
Some variation (a few days earlier or later each month) is completely normal. Cycles can also shift due to stress, illness, travel, or major life changes.
common normal symptoms
What's "normal" varies person to person. What matters most is knowing YOUR normal, so you can notice when something changes.
period pain
Period pain (dysmenorrhea) is extremely common, but the cause and severity vary widely. It's important to distinguish between pain that's a normal part of menstruation and pain that could signal an underlying condition.
Primary Pain
Normal process- Cramping caused by prostaglandins (natural chemicals that make your womb muscle contract), a normal hormonal response
- Usually worst on day 1–2, then fades within a few days
- Manageable with heat, rest, and OTC pain relief (ibuprofen/naproxen)
Secondary Pain
Needs attention- Caused by an underlying condition (endometriosis, fibroids, adenomyosis…)
- Often gets worse over time, not better with age
- Needs a doctor's evaluation. Don't normalize worsening pain
Sources: WHO, ACOG, NIH. Not a substitute for medical advice.