Cycle × body · 6 min
Abdominal pain before period — causes, mechanism, and when to take it seriously
Abdominal pain in the last days before menstruation is one of the most commonly reported cycle symptoms. The mechanism is well documented: prostaglandins — substances produced in the endometrium just before it sheds — cause uterine contractions and can irritate the bowel. It's the same mechanism that produces typical menstrual cramps once bleeding begins.
What it feels like
- Dull pressure in the lower abdomen, sometimes radiating to the lower back.
- Cramps resembling mild menstrual pain.
- Bloating, sense of fullness.
- Looser stools or diarrhea in the last 1–2 days before menstruation.
- Tenderness on light pressure, but no sharp focal pain.
Why it's not "in your head"
Prostaglandin concentration in the endometrium rises at the end of the luteal phase. In people with stronger sensitivity to these substances, pain appears 1–3 days before bleeding. It's physiology, not imagination — and it doesn't need justification.
When it's no longer ordinary PMS
Take a closer look when:
- Pain starts 5–10 days before menstruation, not 1–2 — a signal worth discussing under suspicion of endometriosis.
- Pain is one-sided, sharp, stabbing — especially around or after ovulation.
- Pain is accompanied by intermenstrual bleeding or spotting lasting >3 days.
- Pain doesn't ease once menstruation starts — it intensifies.
- Standard NSAIDs (ibuprofen, naproxen) stop working.
- Pain causes vomiting, fainting, or missed work/school days.
Endometriosis — why it comes up
Average diagnostic delay for endometriosis is 7–10 years. One reason: premenstrual pain gets normalized — both the patient and the clinician accept that it's "just how it is". With 2–3 cycles of symptom tracking (when it starts, how long, intensity, what helps), the gynecology appointment becomes specific. Without it — you come back in a month asked to start tracking.
What actually helps
- NSAIDs taken prophylactically 1–2 days before expected pain (more effective than reactive use).
- Heat on the lower abdomen — comparable to mild NSAIDs in some studies.
- Continuous hormonal contraception — eliminates bleeding, and pain, for many.
- Magnesium (300–400 mg) in the second half of the cycle — moderate evidence.
- Low-intensity physical activity — raises pain threshold.
What doesn't help (myth)
- "Just relax" — the pain is biochemical, relaxation doesn't lower prostaglandins.
- Herbal detoxes — no evidence of real effect on menstrual pain.
- Cutting gluten/dairy without indication — placebo, or unrelated to cycle.
What's worth logging
If pain is cyclical, daily entries (when it started, intensity 1–10, duration, what helped) for 2 months give you actual data for a decision. Without it, the conversation with a doctor leans on memory — which preserves only the worst days.