What causes bleeding before an expected period?

Bleeding before an expected period, known as spotting or breakthrough bleeding, can have several causes:

1. Hormonal Imbalance: Hormonal fluctuations during the menstrual cycle, particularly an increase in estrogen and progesterone, can cause the uterine lining to shed, resulting in spotting.

2. Implantation Bleeding: When a fertilized egg implants into the uterine wall, it can lead to light bleeding or spotting. This usually occurs around the time when a period is expected.

3. Contraception: Starting a new oral contraceptive or switching birth control methods can disrupt hormone levels, leading to breakthrough bleeding.

4. Infections: Sexually transmitted infections (STIs) or other pelvic infections, such as vaginitis, may cause irregular bleeding.

5. Stress: Physical or emotional stress can disrupt hormone levels and lead to spotting.

6. Pregnancy Complications: Spotting can occur during early pregnancy and may be a sign of a miscarriage, ectopic pregnancy, or other complications.

7. Polyps, fibroids, or tumors: Growths in the uterus, such as polyps, fibroids, or cancerous tumors, can cause abnormal bleeding.

8. Medication side effects: Certain medications, such as blood thinners or hormone therapy, may lead to spotting.

9. Postmenopausal Bleeding: Women who have gone through menopause may experience spotting as a result of changes in hormone levels.

10. Perimenopause: During the transition period before menopause, hormonal changes can cause irregular bleeding patterns.

If the bleeding is heavy, persistent, or accompanied by other symptoms such as pelvic pain, fever, or a change in your menstrual cycle, it's essential to consult a healthcare professional to determine the cause and receive appropriate treatment.