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Think of your period as a sort of mood ring for your body. Color variations can be a unique personality trait of your uterus — or they could be a sign of something more serious.

Although most blood colors aren’t a cause for concern, some could be a reason to visit your doctor.

Brown period blood can indicate a couple of things. It can be an early sign of pregnancy or a normal part of your cycle. Let’s break it down.

Your period is starting or ending

Brown period blood is common at the beginning and end of your cycle, when your flow is slower. Blood that stays in your body longer becomes oxidized and darkens in color. The result is brownish discharge.

You’re pregnant

Brownish blood or spotting can be a sign of implantation bleeding — an early sign of pregnancy that occurs roughly 10 to 14 days after conception.

Other signs of implantation include mild cramping, an increased body temperature, swollen breasts, nausea, and vomiting.

You’ve recently given birth

After giving birth, you might experience lochia, postpartum bleeding that can last for 4 to 6 weeks. Lochia starts out heavy, but around day four, the blood often becomes pinkish or brown.

You’re experiencing a missed miscarriage

A missed miscarriage happens when the fetus stops developing but doesn’t pass through your uterus for at least 4 weeks. Some women experience heavy, bright red bleeding and clotting, while others have dark brown spotting or moderate bleeding.

If you’re pregnant and you experience bleeding of any color, it’s always a good idea to check in with your doctor.

You have PCOS

Missed periods could be a sign of polycystic ovary syndrome, which can cause darker discharge, irregular bleeding, and spotting in between periods.

Other signs of PCOS include:

  • excessive hair growth
  • oily skin or acne
  • weight gain

Period blood that’s black can be alarming, but like brown blood, it’s usually just older blood that has taken its sweet time exiting your body. It usually occurs at the beginning or end of your period when the flow is low.

Less commonly, black blood can indicate a missed miscarriage or a blockage in your vagina.

Other signs of a blockage include:

  • foul-smelling discharge
  • fever
  • difficulty peeing
  • vaginal irritation (itching or swelling)

Dark red blood is blood that’s almost ready to turn brown or black but hasn’t had enough time to oxidize. Most often it’s the blood that flows out first thing in the morning after sitting in your uterus overnight.

Here are some other times dark red blood might show up:

Near the end of your cycle

It’s normal to see the blood in your flow darken toward the end of your cycle. This just means the blood is moving slowly and has had more time to oxidize.

During lochia (postpartum bleeding)

After giving birth, you might experience heavy bleeding that contains clots. The blood is often dark red for the first 3 days and then transitions to darker shades as the flow slows.

Bright red blood usually occurs early on in your flow. This is fresh blood that passes out of your body quickly, after having little time to oxidize.

Occasionally, bright red blood can signal an abnormal menstrual flow. If you’re bleeding through several pads, tampons, or menstrual cups per hour, something may be up.

Infection

Sexually transmitted infections (STIs) like gonorrhea or chlamydia can cause bleeding between periods.

Other signs of an STI include:

  • foul-smelling discharge
  • pain during sex
  • a frequent, urgent need to pee

If you suspect an STI, it’s a good idea to contact your doctor ASAP.

Uterine growths

Fibroids or polyps are noncancerous growths in the uterus and can cause unusually heavy bleeding. They range in size and can cause other symptoms, like abdominal pressure or pain.

Adenomyosis

Heavy bleeding is a symptom of adenomyosis, which occurs when tissue that normally lines your uterus grows into your muscle tissue instead. This leads to thicker uterine tissue that causes longer, heavier periods and pain during menstruation and intercourse.

Cervical cancer

Rarely, bright red bleeding can be a sign of cervical cancer.

Other warning signs include:

  • heavier or longer-than-usual periods
  • bleeding after sex
  • foul-smelling discharge
  • lower back pain, leg pain, or pelvic pain
  • loss of appetite
  • unexplained weight loss

If you’re pregnant

Bleeding during pregnancy isn’t always a cause for concern. Pregnancy is different for every woman. For some, bleeding could be a sign of miscarriage, but for others it’s not.

Sometimes women who experience bleeding go on to deliver healthy babies. But it’s always a good idea to check in with your doctor if you see blood during your pregnancy.

Pink period blood happens when your period blood mixes with cervical fluid.

Here are some possible reasons for it:

Low estrogen

Using hormonal birth control, particularly a type that’s low in estrogen (like the mini pill or Mirena IUD), can lead to lighter, pink-toned periods.

This can also be a sign of perimenopause, the beginning stage of menopause.

Other signs of low estrogen include:

  • mood swings
  • hot flashes
  • pain during sex
  • breast tenderness
  • irregular or missing periods

Ovulation

Ovulation occurs midcycle when one of your ovaries releases an egg. It’s normal to see some light pink spotting around this time.

Lochia

Toward the end of lochia, usually on day four and onward, it’s normal for blood to turn a pinkish or brownish color.

Orange period blood, like pink period blood, is usually the result of period blood mixing with your cervical fluid, lightening the color of your flow.

It could be implantation bleeding, which is typically light pink or orange. Not all pregnant peeps experience this, though.

Your period blood shouldn’t be gray. If it is, call your doctor and have them check it out.

Gray blood can be a sign of an infection like bacterial vaginosis, which is caused by an overgrowth of the natural bacteria in your vagina. Be on the lookout for other symptoms like fever, pain, itching, odor, or a burning sensation when you pee.

Clots are a normal part of a healthy flow. For your period blood to leave your body, your cervix has to contract (hello, cramps) to expel the contents of your uterus.

Your body releases anticoagulants (aka blood thinners) to allow everything to pass more freely, but when your flow outpaces the speed at which that process happens, you’re left with clots.

Clotting is most common on heavy flow days. It’s usually nothing to worry about, as long as the clots are smaller than a quarter and are bright or dark red.

Large clots

But clotting can also be an indication of something wrong, such as adenomyosis, endometriosis, fibroids, a hormonal imbalance, cancer, or a bleeding disorder called Von Willebrand disease.

Keep an eye out for clots that are larger than a quarter and are accompanied by other symptoms like pelvic pain, difficulty getting pregnant, pain during sex, gastrointestinal issues, and weight loss or gain.

If you’re pregnant and experiencing heavy bleeding or clotting, it might be an symptom of miscarriage.

Anemia

If you’re passing large clots regularly, you might want to ask your doctor to check for anemia. Some symptoms of anemia are fatigue, weakness, paleness, shortness of breath, and chest pains.

You know your body better than anyone else. Talk to your doctor if anything about your cycle seems off, especially if you have signs of an infection.

This is extra important if you have any bleeding during pregnancy. Some spotting and bleeding can be normal, but it might mean you’re experiencing a miscarriage or some other pregnancy complication.

It’s also time to touch base with your doctor if you’re bleeding through multiple pads per hour or have period pain that lasts longer than a few days and requires pain relievers.

Your period shouldn’t keep you from school, work, or socializing. If it does, you could be dealing with a condition like endometriosis, adenomyosis, or fibroids.

Remember:

Excessive bleeding and severe period pain are not normal, and you shouldn’t have to just deal with them. Your doctor can help you figure out the cause and find some relief.

Trust your gut and try to stay calm. Lots of things that look alarming, like black period blood or clots, are usually no big deal.

On the other hand, many women are told period pain and heavy bleeding are just normal parts of their cycle, when in reality those things can indicate an underlying health issue.

When in doubt, talk to your doctor. And if necessary, seek a second opinion. Just say no to painful periods.