This article will explain common causes of bloody discharge, when to see a healthcare provider, and how to treat or prevent it in the future.

Causes of Bloody Discharge

Bloody discharge does not always indicate that something is wrong. In fact, there are many cases where it points to normal bodily responses.

Menstrual Cycle

Menstruation, the shedding of the uterine lining, is the most common form of bloody discharge. It can indicate the beginning of your menstrual cycle or period. A regular period occurs, on average, every 28 days or about 14 days after regular ovulation.

The color of your period may change during your cycle, starting with pink, brown, or black blood and transition into burgundy or red blood.

During Early Puberty

Age is often a factor in irregular menstruation. Menarche, or the onset of menstruation, is a normal process that usually occurs around the age of 12 in girls.

After getting your first period, it’s common to not get another period for a few months, causing bloody discharge to appear on an irregular schedule. This is because it can take a while for the hormone cycle that is responsible for ovulation and regular menstruation to mature.

Perimenopause and HT

Perimenopause is the phase leading up to menopause—or your last period. In general, most women begin noticing perimenopausal symptoms in their 40s, with the average age being 47 years old.Menstrual cycle changes are normal during perimenopause. Your periods may be shorter, longer, heavier, or lighter than usual. You may even miss some periods.

Hormone therapy, or HT, refers to a combination of the female hormones estrogen and/or progesterone medication. Some women may be prescribed these to lessen perimenopause and menopause symptoms. One known side effect of HT is irregular bleeding.

While bleeding during pregnancy may be a problem, it’s actually quite common during the first trimester, or first three months of a normal pregnancy.

About 15% to 25% of pregnant women have bleeding in the first trimester. The bleeding is typically light and occurs after fertilization (when the fertilized egg implants in the lining of your uterus). This type of bleeding is also sometimes called implantation bleeding and isn’t cause for concern.

While implantation bleeding is common, always check in with your healthcare provider about bleeding during pregnancy because it can be an indication of something more serious.

Concerning Causes of Bloody Discharge

In some cases, bloody discharge or bleeding between periods can point to more severe conditions. In all cases, it’s important to track your symptoms holistically and see your healthcare provider, as bloody discharge is often one of many symptoms that help lead to a diagnosis.

Endometriosis

Endometriosis is a chronic inflammatory condition in which tissue normally found in the uterine lining forms in other organs of a woman’s reproductive or endocrine system.Symptoms vary in severity and can cause irregular menstrual bleeding or spotting between periods. Endometriosis is challenging to diagnose, so it’s important to monitor other symptoms like severe cramps, unexplained pelvic pain, painful sex, fatigue, and bladder problems.

Cancer

Many common cancers experienced by women rarely cause symptoms at early stages. If early symptoms do occur, it’s often bleeding or spotting outside of menstruation.

Uterine cancer is the most common gynecological cancer in the United States. It primarily refers to two types of cancer that affect the uterus: Endometrial carcinoma and uterine sarcoma. Both can lead to bleeding between menstrual cycles or after menopause, among other symptoms.   Cervical cancer occurs in the cervix and most cases are attributed to the human papillomavirus (HPV), a sexually transmitted infection (STI). One of the most common early symptoms of cervical cancer is irregular bleeding. This can occur outside of menstruation, in excess during menstrual bleeding, or bleeding after intercourse. Ovarian cancer affects a woman’s ovaries and surrounding structures. There are often no early symptoms. But younger ovarian cancer patients often have germ cell tumors (tumors that start from the cells that produce the eggs), or sex cord stromal tumors (structural tissue cells that hold the ovary together and produce the female hormones estrogen and progesterone).  In these cases, abnormal vaginal bleeding or bleeding similar to a period is a common symptom.

Burst Ovarian Cyst

An ovarian cyst is a fluid-filled sac that forms within or on top of an ovary. They are common and usually resolve on their own, but in some cases can burst and be associated with abnormal bleeding or bloody discharge.

A burst ovarian cyst will usually cause sharp and sudden pain located on one side of the pelvis. This often happens after sex or strenuous activity.

Infectious Causes

Vaginosis: Bacterial vaginosis (BV) is a common condition in which the normal balance of the vaginal flora is disrupted due to sex, body products, or antibiotics, leading to an overgrowth of anaerobic bacteria. Symptoms are usually mild but can include bleeding after sex, burning sensation when urinating, or a “fishy” odor.   STIs: Bleeding or spotting between periods can also be a symptom of an STI, like chlamydia, gonorrhea, or trichomoniasis. STIs symptoms may be accompanied by abnormal discharge, or pain or itching in the vaginal region.  

Pregnancy Problems

While bleeding during early pregnancy is common, you should always check in with your healthcare provider because in some cases it can be cause for concern.

Ectopic Pregnancy: One cause of bleeding in early pregnancy that is not normal is an ectopic pregnancy. An ectopic pregnancy occurs when the fertilized egg implants somewhere other than the uterus wall, typically in one of the fallopian tubes. Vaginal bleeding is sometimes the only sign of an ectopic pregnancy. Miscarriage: While very upsetting but not uncommon, miscarriage (also called early pregnancy loss) is the loss of a pregnancy before the 20th week (or roughly four and a half months) of pregnancy. Typical symptoms of a miscarriage include bleeding (from spotting to heavy) along with fluid and tissue discharge. Preterm Labor: Labor that begins before 37 weeks is called premature or preterm labor. Signs and symptoms of preterm labor include a change in vaginal discharge (bloody, watery, mucus), abdominal or pelvic pain, and contractions.

Thyroid Disease

The thyroid gland is a small butterfly-shaped gland located at the base of the front of your neck. In addition to controlling metabolism, heart rate, and other functions, the thyroid hormone plays an essential role in reproductive health. 

Women are 10 times more likely to develop thyroid disease than men, which can lead to complications in menstruation. Too much or too little thyroid hormone can make your periods very light, heavy, or irregular. Thyroid disease also can cause your periods to stop for several months or longer, a condition called amenorrhea.

Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a chronic condition that affects about 1 in 10 women of childbearing age and can impair fertility. The symptoms of PCOS vary making this chronic disease so confusing.

One common symptom of PCOS is irregular, absent, or heavy menstruation. That’s because people with PCOS typically have higher levels of male hormones called androgens, which throw off the ratio of female sex hormones (like the ones that control your menstrual cycle).

This can lead to absent periods for several months or irregular ones that may come two or more times in one month.

Obstructive Causes

Bleeding doesn’t always point to a medical condition. Sometimes common obstructions can cause bloody discharge.

Retained tampon: It’s easy to lose track of a tampon inside the vagina. Forgetting to remove one before sex or before inserting another can cause discomfort and in some cases bloody discharge. IUD: An intrauterine device (IUD) is a small, flexible, plastic device that is shaped like the letter T. It’s inserted into the uterus to prevent pregnancy. Some IUDs may make menstrual periods lighter or stop a woman from having them altogether. Spotting between periods is common in the first three months after insertion.

Anatomical Causes

Bloody discharge can also point to benign growths or masses in the genital region.

Polyps: Uterine polyps, also called endometrial polyps, are usually small, bulb-shaped masses of endometrial tissue attached to the uterus by a stalk. Many people experience abnormal uterine bleeding, which includes spotting between periods or after intercourse. Fistulas: A fistula is a passage or hole that has formed between two organs or an organ and skin. A fistula that has formed in the wall of the vagina is called a vaginal fistula. There are several types of genital fistulas. In all cases, symptoms may include fluid leaking or flowing out of your vagina, including blood or puss.  

When to See a Healthcare Provider

Any unexplained vaginal bleeding between periods is a reason to see your healthcare provider. It is especially important if you haven’t yet gone through puberty, if you are past menopause, or if you are pregnant.

If menstruating, your healthcare provider might ask you questions about when it occurs, how long it lasts, and how heavy the bleeding is. Consider keeping track of your cycle using an app, a calendar, or a diary.

In addition, your healthcare provider may ask questions about any other symptoms you’re experiencing. So monitoring any pain, dizziness, or other discharge will help direct them to a cause.

To help diagnose your bloody discharge, they may perform a pelvic exam, blood tests, colposcopy, ultrasound, hysteroscopy, or other diagnostic tests.

Summary

Bloody discharge can be normal and isn’t always a sign of an emergency. There are many cases where it is a normal body response. When bloody discharge occurs during menopause, later in pregnancy, or is accompanied by other symptoms, it may point to a more severe condition. Age, lifestyle, and medical history all come into play when determining the cause of bleeding outside of menstruation, so it’s important to track your symptoms and see your healthcare provider.

A Word From Verywell

Seeing blood in your underwear when you’re not expecting it can be alarming. Our bodies are in constant communication with us, using symptoms to clue us into natural processes or unusual conditions. When it comes to bloody discharge, it’s not always bad news. Keeping track of your period is a simple way to help understand the cycles of your body, what’s normal for you, and what should be flagged.