The short explanation
Sudden sharp pain low on one side with light bleeding and a late period needs urgent medical attention. One important possibility is an ectopic pregnancy, where a pregnancy grows outside the womb, usually in a fallopian tube. This can cause internal bleeding and is an emergency. It can happen even if you used contraception or had a negative test earlier. Other causes include a burst or twisted ovarian cyst, appendicitis or a miscarriage. These also need prompt care. Please do not wait to see whether it settles.
What depends on your situation
The parts of this that change from woman to woman. Uncertainty is stated, not hidden.
- Warning signs of internal bleeding include feeling faint or dizzy, pain in the tip of the shoulder, a fast heartbeat, pale or clammy skin and pain when passing stools.
- At the hospital, doctors usually do a pregnancy test, blood tests and an ultrasound. These help to tell the causes apart quickly.
- If you are alone, ask someone to go with you. Government hospitals have emergency departments that can see you at any hour.
What this answer cannot determine
The boundary of online education. These need a clinician who can see you.
- This answer cannot tell what is causing your pain. It needs urgent examination, a pregnancy test and usually a scan.
Questions for your clinician
Take these with you. You can add any of them to an appointment card.
- Could this be an ectopic pregnancy, and how will we check?
- What did the scan show?
- What happens next if it is an ovarian cyst or ectopic pregnancy?
- What should I watch for after I go home?
When to seek help
Clinician-approved guidance for this topic. When in doubt, being seen is never the wrong choice.
Emergency — call 112 now
- Call 112 or go to the nearest emergency department now if you have sudden severe one-sided pain, especially with fainting, dizziness, shoulder-tip pain or heavy bleeding.
Get help the same day
- Get care the same day, within hours, if you have one-sided pain and a late period even if the pain is milder.
Sources
The evidence this explanation is built on.
- Pelvic pain NHS
- Pelvic pain MedlinePlus (NIH)
- Stopped or missed periods NHS
Who wrote and reviewed this
Every AskHer answer names its author. A clinically reviewed answer also names the clinician who signed it off — if no clinician is named below, it has not been clinically reviewed.
- Author
- AskHer Editorial (AI-assisted draft) AskHer's editorial team — not an individual clinician Works in English, தமிழ், हिन्दी
- Clinical reviewer
- Nobody yet No clinician has signed this answer off, and no person on the editorial team has read it yet. That is what the “Written with AI assistance” label means. It is queued for an editor to read, and then for a clinician who works in this area. The sources it was drafted against are listed above.
- Review status
- Written with AI assistance — not yet reviewed by a person
- Last reviewed
- Not yet reviewed by a person
- Version
- 1
Correction history
Substantive changes are listed, not quietly edited away.
No corrections have been made since this answer was first published.
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