Why is my period darker than usual?
Last updated September 3, 2026.
Almost always oxidation: blood darkens as it ages - brown or rust at the start or end of a period, or in slow light months, is older blood that lingered before leaving. It looks alarming and means almost nothing alone. The meaningful variations: bright red heavy flow matters only when soaking-heavy or clot-heavy; gray with a bad smell is infection (or a retained tampon - urgent), not period blood. The flags: missed period with dark spotting and one-sided pain (test - ectopic is same-day), recurring dark spotting between periods, or a change that persists across several cycles.
What to do
- Expect brown at the edges. Start and end of flow: old blood, normal.
- Test for pregnancy with odd spotting. Especially with one-sided pain.
- Treat gray and foul as infection. Same-week care; retained tampon is urgent.
- Track persistent changes. Three cycles of new pattern: bring the log in.
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