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What is Black Menstrual Blood?

What is black menstrual blood? We explain what black discharge means

Dots, particles, clots and lines. Shades ranging from pink, brown, red and all kinds of colors. As we all know, there is no limit to the different situations regarding menstrual periods. However, if you check your Modibodi menstrual panties and notice black menstrual blood in them, you may feel a little worried.

It may be scary, but we're here to tell you that black menstrual blood is "usually" completely normal. There are many reasons that can cause black blood and we have compiled some of the common causes of black menstrual blood for you.

Why is my period blood black?

We can see different types of things when washing your Menstrual Panties and black blood is no exception. As blood remains in our body, it oxidizes through exposure to oxygen and turns from red to brown and eventually black.

You usually see this black discharge at the beginning or end of your menstrual period, but it can occur at any time. Don't worry though. Black menstrual blood is a natural occurrence for the following reasons:

  • Each menstrual period is different. The color of blood may change during menstruation.
  • When the lining of the uterus stops shedding, blood flow slows down. Therefore, it takes longer to pass through the vaginal area.
  • Blood from your previous periods may remain in the uterus and come out during your next period.

These are part of being a menstruating person. A small amount of black menstrual blood is not a cause for concern. However, if you notice large amounts and/or other symptoms, you may need to look for other causes.

Other causes of black menstrual blood

Apart from the fact that the uterus takes a little longer to shed blood and tissue, black menstrual blood can occur for a few other reasons. Here are some common reasons behind darker discharge:

  • sexually transmitted infections
  • Endometriosis, PCOS and other conditions
  • Hormones
  • implantation bleeding
  • foreign bodies
  • postpartum
  • Cervical cancer

sexually transmitted infections

Sexually transmitted infections, such as chlamydia and gonorrhea (genorrhea), can cause blood to rapidly decompose and turn into dark discharge. If an STD is suspected, it is important to get it checked out immediately as it can cause serious conditions, infertility, and pelvic inflammatory disease.

Endometriosis (Chocolate Cyst), PCOS and other conditions

Black blood can sometimes be a result of conditions such as endometriosis and PCOS (Polycystic Ovary Syndrome), which affect the uterus and ovaries. Black menstrual blood sometimes resembles coffee grounds and can last up to 7 days in those with endometriosis.


Hormonal changes can cause many things in our body. Unsurprisingly, hormones can also lead to black menstrual blood. Thyroid problems, premenopause, and excessive uterine stress can cause blood oxidation and changes in the lining of the uterus.

implantation bleeding

A quarter of pregnant people will experience implantation bleeding as a result of the embryo implanting in the lining of the uterus. Since there is only a small amount of blood that may take longer to pass through the vaginal area, black menstrual blood can be a sign of pregnancy.

foreign bodies

Forgotten or stuck foreign objects, such as tampons and birth control devices, can become stuck in the vagina and cause infection. Sometimes sex toys, like condoms and the diaphragm, can irritate the vaginal wall, leading to an infection that can cause black blood discharge.


Postpartum bleeding and vaginal discharge is called “Louchia” and can continue for up to 8 weeks after birth. During the first 5 days, the blood is mostly oxidized, so it may appear black or dark brown.

Cervix (cervix) cancer

Unfortunately, symptoms of cervical cancer may not always appear. However, symptoms may include irregular menstrual periods and bleeding after sexual intercourse. If you are experiencing bothersome symptoms, it is important to consult your healthcare provider.

Time to see a doctor

We understand, seeing black menstrual blood and discharge can be upsetting. Although black menstrual blood is generally normal, if it causes concern, it would be beneficial to consult your doctor.

If black blood occurs along with other symptoms such as pelvic pain, pain during and after sexual intercourse, watery discharge, or an unpleasant odor, you should get checked by a healthcare professional. Likewise, it is important to inform your doctor if the black blood becomes more intense or lasts longer than 2 days.

Stay in touch with your body

Modibodi menstrual panties make it easier to notice changes in your menstrual cycle and stay connected to your body. Browse the leak-proof underwear options and find the one that suits you best.

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