(HealthDay News) -- Menstrual bleeding typically occurs about every 28 days, and lasts for about four days at a time.
Vaginal bleeding that occurs outside of the menstrual cycle has many potential causes, and should be evaluated by a doctor.
Here are possible reasons for vaginal bleeding between menstrual cycles, courtesy of the U.S. National Library of Medicine:
- Cancer of the cervix, uterus or, rarely, fallopian tubes.
- A side effect of certain procedures, including cervical or endometrial biopsy.
- Stress or changing hormone levels.
- Uterine fibroids or polyps, or vaginal dryness.
- Pregnancy complications, including ectopic pregnancy or miscarriage.
- Disease or injury to the vaginal opening.
- Using an IUD, or stopping or starting the birth control pill.
- An underactive thyroid.
- Taking a blood thinner.