Implantation and menstrual periods are not the only causes of vaginal bleeding. These are some other possible causes.
- Early pregnancy complications, such as ectopic pregnancy or miscarriage
- Growths, such as cervical polyps, endometrial polyps, uterine polyps, or uterine fibroids
- Hormone fluctuations from thyroid disease, polyendocrine metabolic ovarian syndrome, or birth control pills
- Infections like vaginitis, chlamydia, gonorrhea, or cervicitis
- Irritation from sex, an injury, a Pap smear, obstetric or gynecological surgery, or sexual abuse
- Certain cancers, including uterine cancer, vaginal cancer, cervical cancer, or ovarian cancer
- Other medical conditions, such as celiac disease, obesity, kidney or liver disease, or blood-clotting disorders
Editor’s Note: Following a May 2026 global consensus, polycystic ovary syndrome (PCOS) is now officially called polyendocrine metabolic ovarian syndrome (PMOS), highlighting the metabolic roots of the condition.
Hormonal Birth Control
Hormonal birth control can also cause bleeding or spotting, which doctors call “breakthrough bleeding.” Any type of hormonal birth control method can cause this symptom, including a pill, implant, shot, patch, vaginal ring, or intrauterine device.
Breakthrough bleeding is more common in people who take a continuous dose of hormones to skip their period and those who smoke cigarettes.
Stress
During stressful times, your body produces more of hormones like cortisol and endorphins. These hormonal changes can make periods more erratic. Some periods may be late, and some people may skip them entirely, when stress is long term.
Significant weight gain or loss, infection, and extreme exercise can also lead to irregular bleeding.
