Brown vaginal discharge may look alarming, but it isn’t always a reason for concern.

You may see this color throughout your cycle, usually around the time of menstruation.

Why? When blood takes extra time to exit the body from the uterus, it oxidizes. This can cause it to appear light or dark brown in color.

If you’re experiencing brown discharge, take note of its timing and other symptoms you encounter. Doing so may help you pinpoint the underlying cause.

Your menstrual flow — the rate at which blood exits the vagina from the uterus — is generally slower at the beginning and end of your period.

When blood leaves the body quickly, it’s usually a shade of red. When the flow slows, the blood has time to oxidize. This causes it to turn brown or even black in color.

If you see brown blood at the beginning or end of your period, this is completely normal. Your vagina is simply cleaning itself out.

Other times, brown discharge may signal a hormonal imbalance.

Estrogen helps stabilize the endometrial (uterine) lining. If you have too little estrogen circulating, the lining may break down at different points throughout your cycle.

As a result, you may experience brown spotting or other abnormal bleeding.

Low estrogen may also cause:

  • hot flashes
  • insomnia
  • mood swings or depression
  • difficulty concentrating
  • urinary tract infections
  • weight gain

Hormonal contraception, like birth control pills, may lead to spotting in the first months of use.

Breakthrough bleeding is more common if your contraceptive contains less than 35 micrograms of estrogen.

If there’s too little estrogen in the body, your uterine wall may shed between periods.

And if this blood takes longer than is typical to leave the body, it may appear brown.

If your spotting continues for more than three months, consider talking to a doctor about changing birth control methods. A contraceptive with more estrogen may help stop the spotting.

A small number of people — around 3 percent — experience ovulation spotting at the midpoint of their menstrual cycles. This is when the egg is released from the ovary.

The color of the spotting may range from red to pink to brown and may also be mixed with clear discharge.

Other symptoms of ovulation include:

  • discharge that has an egg white consistency
  • low abdominal pain (Mittelschmerz)
  • a change in basal body temperature

Keep in mind that you’re most fertile in the days before and including ovulation.

Ovarian cysts are fluid-filled pockets or sacks that develop on one or both ovaries.

A follicular cyst, for example, may develop if an egg doesn’t successfully burst from the ovary at the time of ovulation. It may not cause any symptoms and it may go away on its own after a few months.

Sometimes, the cyst doesn’t resolve and may grow larger. If this happens, it may cause anything from brown spotting to pain or heaviness in your pelvis.

Cysts of any type that continue to grow risk rupturing or twisting the ovary. If you suspect that you may have a cyst, see a doctor or other healthcare provider.

Sexually transmitted infections (STIs) may lead to brown spotting or bleeding.

Some infections, such as gonorrhea or chlamydia, may not cause symptoms in the beginning stages.

In time, possible symptoms include pain with urination, pelvic pressure, vaginal discharge, and spotting between periods.

Bacterial vaginosis (BV) is another possible infection that isn’t necessarily transmitted with sexual contact.

Instead, it’s caused by an overgrowth of bacteria that can lead to changes in the texture, color, or smell of your discharge.

It’s important to see your doctor if you suspect you have an STI or other infection.

Without treatment, you may develop what’s called pelvic inflammatory disease (PID) and risk infertility or chronic pelvic pain.

Endometriosis is a condition where the uterine lining grows in places outside of the uterus. It may cause anything from painful, heavy periods to spotting between periods.

Without a way to exit the body when it is shed, the endometrium becomes trapped and may cause severe pain, brown discharge, and fertility issues.

Other symptoms may include:

  • bloating
  • nausea
  • fatigue
  • constipation
  • diarrhea
  • painful urination
  • pain during vaginal sex

With PCOS, you may experience irregular or infrequent menstrual periods.

You may have as few as nine periods a year, or more than 35 days between each menstrual period.

You may develop ovarian cysts and experience brown spotting between periods due to skipped ovulation.

Other symptoms may include:

  • headaches
  • acne
  • darkening of the skin
  • thinning hair or unwanted hair growth
  • depression, anxiety, and other mood changes
  • weight gain

Implantation occurs when a fertilized egg embeds itself into your uterine lining.

It happens 10 to 14 days after conception and may cause light bleeding of various shades, including brown.

Other early pregnancy symptoms may include:

  • uterine cramping
  • bloating
  • nausea
  • fatigue
  • aching breasts

Consider taking a home pregnancy test if your period is late or you’re experiencing brown spotting in its place.

If you receive a positive test result, make an appointment with a doctor or other HCP to confirm your results and discuss next steps.

Sometimes a fertilized egg may implant itself into the fallopian tubes or in the ovary, abdomen, or cervix. This is called an ectopic pregnancy.

In addition to brown spotting, ectopic pregnancy may cause:

  • sharp pain in the abdomen, pelvis, neck, or shoulder
  • one-sided pelvic pain
  • dizziness
  • fainting
  • rectal pressure

See a doctor or other healthcare provider right away if you’re experiencing any of these symptoms alongside brown spotting.

Without treatment, ectopic pregnancy can cause your fallopian tube to burst. A ruptured tube may cause significant bleeding and requires immediate medical treatment.

Anywhere from 10 to 20 percent of pregnancies end in miscarriage, usually before the fetus reaches 10 weeks of gestation.

Symptoms may come on suddenly and include a gush of brown fluid or heavy red bleeding.

Other symptoms may include:

  • cramping or pain in your lower abdomen
  • passing tissues or blood clots from the vagina
  • dizziness
  • fainting

Bleeding in early pregnancy can be normal, but it’s important to report brown discharge or other unusual symptoms to a doctor.

They can help diagnose the underlying cause and advise you on any next steps.

Lochia refers to a four to six week period of bleeding after childbirth.

It begins as a heavy red flow, often filled with small clots.

After a few days, the bleeding typically slows. It may become more pink or brown in color.

After about 10 days, this discharge changes yet again to more of a yellow or creamy color before it trails off completely.

See a doctor if you develop foul-smelling discharge or fever, or pass large clots. These could be signs of infection.

The months and years before menopause are referred to as perimenopause. Most people begin perimenopause sometime in their 40s.

Perimenopause is characterized by fluctuating estrogen levels. This can cause irregular bleeding or spotting, which may be brown, pink, or red in color.

Other possible symptoms may include:

  • hot flashes
  • insomnia
  • irritability and other mood changes
  • vaginal dryness or incontinence
  • libido changes

After reaching menopause, spotting or bleeding between periods or after sex — of any color or consistency — is the most common sign of endometrial cancer.

Unusual vaginal discharge is also a common side effect of cervical cancer.

Symptoms beyond discharge generally do not arise until cancer has progressed.

Symptoms of advanced cancer may include:

  • pelvic pain
  • feeling a mass
  • weight loss
  • persistent fatigue
  • trouble urinating or defecating
  • swelling in legs

Keeping up with annual pelvic exams and regular discussions with your doctor are key for early detection and prompt treatment.

In many cases, brown discharge is old blood that’s taking extra time to leave the uterus. This is especially true if you see it at the beginning or end of your menstrual period.

Brown discharge at other points in your cycle may still be normal — but be sure to take note of any other symptoms you experience.

You should see a doctor or other healthcare provider if you notice changes in your discharge during pregnancy or experience symptoms of infection.

Seek immediate treatment if you experience irregular bleeding or spotting after menopause.