Brown period blood tends to appear at the end of the menstrual cycle or during ovulation. But if you have other symptoms, it can sometimes indicate another health condition.

You probably know what to expect during your period: how long it will last, when it’ll be the heaviest, and which days you’ll feel the worst. So when you spot something abnormal, such as brown discharge or dark brown blood, you may be concerned.

Every woman experiences menstruation differently. Your cycle might run like clockwork, with few cramps and short periods. Other women may not be able to get out of bed for the first few days of their period, bleed very heavily, and never know how long it will last once it arrives. Even if you have a regular, predictable period, you may notice variation from month to month.

In most cases, brown blood during your period is normal.

The color and consistency of blood can change throughout your menstrual cycle. It may be thin and watery one day, and thick and clumpy the next. It may be bright red or brown, heavy or light. It’s normal for your periods to vary in length, heaviness, and level of discomfort.

Brown blood is usually present toward the end of your cycle. As your body sheds the uterine lining in the first few days of your cycle, the blood is normally red. However, near the end of your cycle, the discharged blood is older and can be discolored.

Sometimes, spotting or brown discharge occurs in the middle of your cycle, during ovulation. This is more common in younger girls who are just starting to have their periods, women starting birth control, or women nearing menopause. When you experience bleeding between periods, you should see a doctor or nurse practitioner to make sure it’s not a symptom of a problem.

Certain types of birth control can cause brown discharge during your period, or even between periods. These include birth control implants such as Nexplanon, known as “the bar.” Birth control affects your hormone levels, so in many cases brown discharge is normal, even at the beginning of your period.

Occasionally, brown, bloody discharge accompanied by other symptoms can indicate a problem.

Tell your doctor right away if you’re pregnant and experiencing brown-colored bleeding. This can mean that something is wrong with your pregnancy. You may need immediate medical care.

Call your doctor if you experience any of the following:

  • periods that last longer than 7 days
  • less than 21 days between periods or more than 35 days between periods
  • not having a period for more than three to six months
  • bleeding between periods
  • bleeding after sex
  • bleeding after menopause
  • spotting (any color) any time during the month
  • pain in your vagina or lower abdomen
  • fever that could indicate an infection
  • fatigue
  • heavy bleeding beyond your normal period flow
  • brown discharge after the insertion of an intrauterine device (IUD)
  • seeing brown discharge when you’re taking tamoxifen, a breast cancer treatment

Polycystic ovary syndrome (PCOS) can also cause brown discharge during your period. Other symptoms of PCOS include:

The cause of PCOS isn’t known. It can be passed on genetically. If your brown discharge happens along with these other symptoms, ask your doctor to test you for it. Untreated PCOS can make you more susceptible to conditions such as type 2 diabetes, infertility, and cardiovascular disease. Getting tested and treated early on can help prevent these issues from developing.

Some causes of brown discharge, including menopause, aren’t a problem. However, discharge can be a symptom of a yeast infection or a sexually transmitted infection (STI) such as gonorrhea or chlamydia, that requires treatment. Brown discharge can also be a sign of inflammatory conditions such as cervicitis or vaginitis. In rare cases, brown discharge can indicate cervical cancer. Talk to your doctor if you think you might have any of these issues. If you haven’t already done so, you may consider getting routine cervical cancer screenings or the human papillomavirus virus (HPV) vaccine.

Some light bleeding or brown discharge is normal during early pregnancy, but any time you have bleeding during pregnancy, you should call your doctor or midwife.

Brown discharge during pregnancy can be a sign of early miscarriage. If you see brown discharge, note whether you have other abnormal symptoms, such as tissue or heavy pink fluid coming out of your vagina. Other warning signs related to early pregnancy include:

If you feel any combination of these symptoms, see your doctor right away to make sure they aren’t signs of a miscarriage or ectopic pregnancy.

Some substances, including cigarettes, alcohol, and illicit drugs like marijuana or cocaine, can cause miscarriages. It’s recommended that you avoid all of these substances completely while pregnant.

A similar discharge that varies in color, called lochia, can appear after you have a baby. Follow your doctor or midwife’s directions about when to follow up.

Brown discharge can also often happen after an abortion. If you have recently had an abortion, follow the directions you were given about who and when to call with symptoms.

As you age, your periods may change. The stage before menopause is called perimenopause. Brown discharge is normal during this stage as long as you don’t experience other abnormal symptoms. Menopause officially begins once 12 months have passed since your last period. During the postmenopausal stage, after you’ve gone 12 months without having a period, you shouldn’t have any bleeding or brown discharge.

Most of the time, bleeding or discharge during menopause isn’t a serious problem. However, blood and discharge can be related to inflammation of your vaginal lining (atrophic vaginitis), noncancerous polyps in your cervix, or other issues in your uterus or cervix including cancer.

If it’s been over a year since you’ve had your last period, see your doctor to identify any issues that may be causing bleeding or discharge. Many conditions that cause postmenopausal bleeding can easily be treated, especially if they’re caught early.

Brown menstrual blood is usually nothing to be concerned about, but talk to your doctor if you feel that your bleeding is abnormal. Also call your doctor if you are troubled by other symptoms that feel out of the ordinary.