Vaginal bleeding has many possible causes, from a normal period to hormonal shifts, pregnancy, infections, or growths in the uterus. The answer depends heavily on timing: whether the bleeding lines up with your cycle, happens between periods, follows sex, or occurs after menopause. Most causes are not dangerous, but some need prompt medical attention.
What Normal Period Bleeding Looks Like
A typical period lasts about 5 days, though anywhere from 2 to 7 days falls within the normal range. Total blood loss is roughly 1 to 5 tablespoons across the entire period. If your bleeding fits that pattern and arrives on a predictable cycle (every 21 to 35 days), what you’re experiencing is likely a standard menstrual period, even if it feels heavier or lighter than usual month to month.
Bleeding becomes a concern when it soaks through a pad or tampon every hour for several hours in a row, lasts longer than 7 days, or shows up at unexpected times. Those patterns point to something beyond normal menstruation.
Bleeding Between Periods
Spotting or bleeding outside your regular period is called intermenstrual bleeding, and it’s one of the most common reasons people search for answers. Several things can cause it.
Ovulation spotting. Some people notice light pink or brown spotting around the midpoint of their cycle, roughly two weeks before the next period. This happens because estrogen drops briefly right after an egg is released, which can cause a small amount of the uterine lining to shed. It’s harmless and usually lasts a day or two at most.
Hormonal birth control. Breakthrough bleeding is extremely common when starting a new contraceptive. Up to 30% of people experience irregular bleeding during the first month on combination birth control pills. The good news: the frequency drops significantly by the third month. IUDs, implants, and injections can also cause spotting, especially early on. If the bleeding persists beyond three months or becomes heavy, it’s worth checking in with your provider.
Infections. Sexually transmitted infections like gonorrhea and chlamydia can inflame the cervix, leading to bleeding between periods. Gonorrhea in particular lists vaginal bleeding between periods as a key symptom. These infections often cause no other noticeable symptoms, so unexpected bleeding can sometimes be the first clue. Left untreated, they can lead to pelvic inflammatory disease, which can affect fertility.
Bleeding Related to Pregnancy
If there’s any chance you could be pregnant, bleeding takes on a different set of meanings.
Implantation bleeding occurs when a fertilized egg attaches to the uterine lining, typically 10 to 14 days after ovulation. It looks more like discharge than a period: light, spotty, and brown or pink in color. It should not soak a pad. If the blood is bright red, heavy, or contains clots, it’s probably not implantation bleeding and could signal something else.
Ectopic pregnancy is a more serious possibility. This happens when a fertilized egg implants outside the uterus, usually in a fallopian tube. The first warning signs are often light vaginal bleeding paired with pelvic pain. A distinctive clue is shoulder pain or a sudden urge to have a bowel movement, which can occur if blood leaks from the fallopian tube into the abdomen. Severe pelvic pain with vaginal bleeding during early pregnancy is a reason to seek emergency care immediately.
Miscarriage is another cause of bleeding in early pregnancy, typically accompanied by cramping and tissue passing from the vagina. Any significant bleeding during a confirmed pregnancy warrants a call to your provider.
Bleeding After Sex
Post-sex bleeding is surprisingly common and usually not serious, but it can be unsettling. One frequent cause is cervical ectropion, a condition where the softer cells normally inside the cervical canal are present on the outer surface of the cervix. Somewhere between 17% and 50% of people with a cervix have this variation. It rarely causes problems, but those delicate cells can bleed lightly with friction during intercourse.
Vaginal dryness is another common culprit, particularly during perimenopause or while breastfeeding, when lower estrogen levels thin the vaginal walls. Insufficient lubrication during sex creates friction that can cause small tears or irritation.
The reason post-sex bleeding still deserves attention is that cervical cancer can produce the same symptom. The bleeding itself is rarely cancer, but it’s one of the reasons routine cervical screening matters.
Uterine Polyps and Fibroids
Growths in the uterus are a common structural cause of abnormal bleeding, particularly heavy periods, bleeding between periods, or periods that are unpredictable in timing and flow. Uterine polyps are overgrowths of the uterine lining that range from the size of a sesame seed to as large as a golf ball. They can cause irregular bleeding, very heavy periods, or spotting between cycles. Some people with polyps have no symptoms at all.
Fibroids, which are noncancerous muscle growths in the uterine wall, cause similar bleeding patterns. They’re particularly common in the 30s and 40s and can make periods significantly heavier or longer than usual. Both polyps and fibroids are typically diagnosed with an ultrasound and are treatable.
Bleeding After Menopause
Any vaginal bleeding after menopause (defined as 12 consecutive months without a period) needs evaluation. Most of the time, the cause is benign: vaginal thinning from low estrogen, polyps, or hormone therapy side effects. But about 9% of postmenopausal people who see a doctor for bleeding are eventually diagnosed with endometrial cancer. That means roughly 1 in 11 cases turns out to be cancer, a high enough rate that even a single episode of postmenopausal bleeding should be checked out. Early-stage endometrial cancer is highly treatable, which is exactly why prompt evaluation matters.
When Bleeding Signals an Emergency
Most abnormal bleeding can wait for a scheduled appointment, but certain situations call for urgent care. You should seek help right away if you’re soaking through one or more pads or tampons every hour for several consecutive hours, if you feel dizzy or lightheaded from blood loss, or if heavy bleeding is accompanied by severe pelvic or abdominal pain. Bleeding during pregnancy with pain, particularly sharp one-sided pain or shoulder pain, also qualifies as an emergency.
Outside of those scenarios, unexplained bleeding that persists for more than a few cycles, bleeding that happens after menopause, or post-sex bleeding that keeps recurring are all worth bringing to a provider. A combination of a pelvic exam, ultrasound, and sometimes lab work can usually identify the cause quickly.