7 Things That Can Cause Spotting Between Periods

Have you ever thought your period was over, only to notice spots of blood in your underwear a few days later? You’re not alone.

Menstrual cycles usually last between 24 and 38 days, with a regular period running anywhere from a few days to about a week. If you bleed between periods, however, it’s considered irregular. Depending on how heavy it is, it can be referred to as spotting or intermenstrual bleeding.

“Spotting can happen at any point in the cycle, but it’s not a steady flow,” says Ma Lourdes Mina, MD, an OBGYN with Coliseum Medical Centers in Macon, Georgia. Spotting can include pink blood on your toilet paper after sex or urination, or spots of blood in your underwear either before or after your period. It’s considered spotting if it’s so light it wouldn’t require the use of a panty liner.

Although most reasons for spotting are benign, like switching birth control, others are more serious. Spotting along with certain other symptoms might point to an underlying condition. In general, if you notice spotting, it’s never a bad idea to schedule a visit with your healthcare provider (HCP). “Any bleeding that is concerning needs to be checked,” says Dr. Mina. Your gynecological practitioner might point to one of the following reasons for your spotting.

Birth control pills stop a person’s egg from being released from the ovaries. This happens because the pill contains hormones—usually estrogen and progestin—that stop the production of hormones that tell your body to ovulate. If the egg is not released, sperm has nothing to fertilize, which prevents pregnancy.

“If you miss a pill, change birth controls in the middle of a pack, or skip your placebo pills, you're adjusting your body’s hormone levels,” says Mina. That manipulation of hormones can cause spotting.

If you notice blood and your menstrual cycle lasts longer than 38 days or is shorter than 24 days, it’s a good time to see your HCP. Oral contraceptives differ in their regimens and certain formulations are continuous, so be sure to discuss the cycle lengths you should expect and when you should report an abnormal length. Remember to mention other medications you take—including over-the-counter drugs, vitamins, and herbal supplements—since certain drugs can interact with the pill and cause spotting.

Emergency contraception is a type of birth control that temporarily stops an ovary from releasing an egg or prevents that egg from being fertilized. It’s technically effective within five days of unprotected sex, though many pills work best when used as soon as possible within the first three days. If you choose to use it, be sure to check with an HCP about timing, and ask which method might be best for you. Certain methods may be less effective for people considered to be obese.

Mina says that it's not uncommon to have spotting or bleeding like a period, or any type of bleeding within that range, when using an emergency contraceptive. “If your spotting lasts longer than a few days, or becomes heavier,” she notes, “you should speak with your gynecologist.”

When you do get your period afterward, it might come earlier or later than what you consider normal.

Any sexually transmitted infection (STI) affecting the cervix can cause bleeding, especially after sex. Two common examples are chlamydia and gonorrhea. If you have painful urination or increased discharge along with your irregular bleeding, it’s important to see your HCP. Chlamydia often comes without symptoms, so even if you are only experiencing irregular bleeding, it’s a good idea to get checked out just to be safe.

Left untreated, these types of STIs can lead to complications like pelvic inflammatory disease (PID), which may also cause bleeding between periods, or even infertility. The good news? Both chlamydia and gonorrhea can be treated with antibiotics, so the sooner you see an HCP for diagnosis and treatment, the better off you'll be.

If you’re sexually active, speak with your HCP about regular STI screening and a Pap test to stay on top of your health.

When you experience perimenopause, the transitional phase leading up to menopause, your menstrual cycle often becomes less predictable than it once was. In some cases, it could get shorter, going from 28 days to, say, 26 days. Some people might skip their period altogether, or it may become heavier or lighter. Other symptoms can include hot flashes, night sweats, and mood swings.

But once you reach menopause (defined as going 12 consecutive months without a menstrual period), it's never normal to experience spotting or vaginal bleeding, so see an HCP if you do. Some common causes for bleeding after menopause include endometrial atrophy (when estrogen levels drop, causing the endometrium, or lining of the uterus, to thin), or endometrial hyperplasia (when the endometrium thickens). Treatment for post-menopausal bleeding will depend on the cause. Prompt diagnosis and treatment of endometrial hyperplasia, in particular, is essential. Left untreated, it can lead to cancer.

Uterine fibroids are tumors that grow in the wall or inside the cavity of the uterus. They may grow as a single tumor or in groups. They're fairly common, especially among those in their 40s and early 50s, and they are nearly always benign (not cancerous).

But if the growth occurs within the innermost layer of the uterus, spotting between periods can result. Other symptoms might include heavy and painful periods, frequent urination, and painful sex. Some people who have uterine fibroids don’t experience symptoms at all.

Treatment will vary depending on the symptoms you’re experiencing as well as the size of the fibroids. Over-the-counter medication or birth control may be used to treat less severe symptoms, while other drugs or even surgical removal of the tumors may be necessary to treat more severe cases.

Fibroids are also genetically linked to endometriosis, another uterine condition that may also cause spotting. The most noticeable symptom of endometriosis, however, is pelvic pain. If you experience pain and spotting, talk to your HCP.

A miscarriage, or a loss of pregnancy, can happen at any time, but usually occurs in the first trimester, sometimes before a person even realizes they’re pregnant. “When people who typically have regular, predictable periods miss a period or have less bleeding than normal, it can be a sign either of pregnancy or a miscarriage,” says Mina. Other symptoms of a miscarriage might include lightheadedness, pain in the abdomen, brown discharge, or other irregular bleeding.

It's important to note that if someone knows they’re pregnant and experiences irregular bleeding, it doesn’t necessarily mean it’s a miscarriage. Spotting during pregnancy isn’t uncommon and can happen at any time. But if you’re pregnant and you experience spotting, call your HCP to discuss your symptoms.

Most cancers of the reproductive organs—including vaginal, cervical, uterine, and ovarian cancer—can have intermittent, abnormal bleeding as a symptom.

If you experience bleeding lasting two weeks or longer, see your HCP. That goes double if you’re having bleeding along with other symptoms such as pelvic pain, bloating, frequent urination, or itching/burning in the vulva. The symptoms for each gynecological cancer vary from person to person and depend on the type of cancer. (For a full list, check the Gynecologic Cancers page from the Centers for Disease Control and Prevention.)

Pap tests can help detect cervical cancers. Other cancers, like ovarian cancer, are harder to detect because there is no formal screening. If the cancer is at a more advanced stage, surgery and chemotherapy might be used for treatment.