Vaginal Bleeding: Causes and When to Worry

What is normal vaginal bleeding?

A typical menstrual cycle in adults:

• comes every 24 to 38 days
• lasts up to 8 days
• varies by no more than 7 to 9 days from one cycle to the next
• loses an amount that does not soak through protection every 1 to 2 hours or interfere with life

Periods are often irregular in the first few years after they start and in the years before menopause (perimenopause).

Causes of abnormal vaginal bleeding

Doctors use the PALM-COEIN system to group causes of abnormal uterine bleeding: structural causes (Polyps, Adenomyosis, Leiomyoma or fibroids, Malignancy) and non-structural causes (Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not otherwise classified). Pregnancy is always considered first.

Pregnancy-related causes

• Implantation bleeding: light spotting around the expected period.
• Miscarriage: bleeding with cramping in early pregnancy.
• Ectopic pregnancy: a pregnancy outside the uterus, causing one-sided pain and bleeding. Life-threatening if it ruptures.
• Later pregnancy: placenta previa, placental abruption or labor.

Hormonal causes

• Ovulatory dysfunction: irregular or absent ovulation, common in teens, perimenopause, polycystic ovary syndrome, thyroid disorders, high prolactin, stress, weight change and excessive exercise.
• Hormonal contraception: breakthrough bleeding, especially in the first months or with missed pills.

Structural causes

• Uterine fibroids: benign muscle growths causing heavy, prolonged periods and pressure.
• Endometrial polyps and cervical polyps: bleeding between periods or after sex.
• Adenomyosis: endometrial tissue in the uterine wall, causing heavy, painful periods.
• Endometrial cancer and endometrial hyperplasia: most often after menopause; risk is higher with obesity, PCOS, diabetes and tamoxifen use.
• Cervical cancer: bleeding after sex or between periods. Regular screening prevents most cases.

Infections and other causes

• Infections: chlamydia, gonorrhea, cervicitis and pelvic inflammatory disease can cause spotting, especially after sex.
• Bleeding disorders: von Willebrand disease is a common, underdiagnosed cause of heavy periods since the teens.
• Medicines: blood thinners, some antidepressants and tamoxifen.
• IUDs: copper IUDs can make periods heavier.
• Vaginal dryness and atrophy after menopause.
• Injury or a foreign body.

Bleeding by life stage

Bleeding after sex

Bleeding after intercourse (postcoital bleeding) is most often from the cervix: cervical ectropion (a harmless area of delicate cells), infection, polyps or, less commonly, cervical cancer. Recurrent bleeding after sex needs a pelvic exam and an up-to-date cervical screening test.

Bleeding after menopause

Any bleeding 12 or more months after the last period should be evaluated promptly. Most causes are benign, but endometrial cancer must be excluded. Found early, it is usually curable with surgery. See vaginal bleeding after menopause.

How doctors find the cause

1. History: timing, amount (pads or tampons per day, clots, flooding), pain, sexual activity, contraception, medicines, pregnancy possibility, family history of bleeding disorders.
2. Pregnancy test for anyone who could be pregnant.
3. Pelvic examination and cervical screening (Pap or HPV test) if due.
4. Blood tests: blood count for anemia, ferritin, thyroid function, prolactin, and clotting tests or von Willebrand testing when indicated.
5. STI tests.
6. Transvaginal ultrasound to look at the uterus lining, fibroids and polyps.
7. Endometrial biopsy for women over 45 with abnormal bleeding, after menopause, or younger women with risk factors.
8. Hysteroscopy: a camera in the uterus to find and remove polyps.

Treatment

Treatment depends on the cause:

• Hormonal treatments: combined pill, progestin pills, the hormonal IUD (very effective for heavy periods) or injections.
• Non-hormonal medicines: tranexamic acid reduces heavy flow; NSAIDs taken during periods reduce flow and cramps.
• Iron supplements for anemia.
• Procedures: polyp removal, fibroid removal (myomectomy), uterine artery embolization, endometrial ablation and, when other options fail or for cancer, hysterectomy.
• Antibiotics for infections.
• Emergency care for ectopic pregnancy and heavy bleeding.

Frequently asked questions

When should I worry about vaginal bleeding?

Seek emergency care for heavy bleeding soaking a pad an hour, dizziness or fainting, or bleeding with severe pain in early pregnancy. See a doctor promptly for any bleeding after menopause, any bleeding in pregnancy, repeated bleeding after sex or between periods, and periods that are much heavier or longer than usual.

What causes bleeding between periods?

Common causes include hormonal contraception, missed pills, ovulation spotting, polyps, fibroids, infections such as chlamydia, cervical changes and early pregnancy. Less commonly, endometrial or cervical cancer. Recurrent bleeding between periods should be checked.

Is spotting normal?

Light spotting can be normal around ovulation, in the first months of hormonal contraception, and occasionally in early pregnancy. Spotting that is frequent, persistent, after sex, or after menopause should be assessed by a doctor.

How much bleeding is too much?

Bleeding is considered heavy if you soak a pad or tampon every 1 to 2 hours, pass clots larger than a quarter, need to change protection at night, or bleed for more than 7 days. Soaking one or more pads an hour for 2 hours is an emergency.

Can stress cause abnormal vaginal bleeding?

Yes. Stress can disrupt the hormones that control ovulation, causing delayed, missed or irregular periods and spotting. Stress should be a diagnosis of exclusion; pregnancy, thyroid problems, PCOS and structural causes should be considered first.