Black Period Blood: Causes, Symptoms and Treatments

Black period blood or black vaginal bleeding is it normal?. This is a common question most women ask. Menstrual blood color ranges from bright to dark red. Dark blood is common at the beginning of period, before period, while on the pill or IUD and also after period.

Most of the time it is nothing to worry about but it may also be a sign of infection, miscarriage, uterine fibroids, polyps or even endometriosis.

Black menstruation blood is normal if it is just an older blood that is getting expelled at a slower rate.

If it is at the beginning of your period, then it is old left over blood from previous menstrual cycle that is been shed away first.

A healthy and normal period blood is usually bright red in color which indicates that the blood is fresh and it is being expelled from the uterus at a fast rate.

Why is my period blood black?

​There are various reasons why your blood could appear darker than normal.

Black or dark blood period occurs when blood is not being expelled from the uterus fast enough. This blood becomes deoxygenated and the colour changes from bright red to black.

This color change indicates the blood has stayed longer it stays in the uterus.

Any abnormal black thick vaginal discharge when pregnant should brought to your doctor's attention immediately.

What causes black brown blood

There are variety of reasons for this black bloody discharge or period. Some are nothing to worry about, while others indicate something is wrong.

1. Old Blood from previous cycle

Some times the uterus doesn't expel all its blood content during the menstruation process.

This left over blood is retained in the uterus which can be expelled as dark brown discharge some days after period or at the start of your next period.

Normally this should go away after the first day of period and your normal bright red period blood should be back.

A thick dark blood is a mixture of an old blood and uterine lining.

2. End of period ​

Another common time, a darker blood flow is noticed is at the end of the menstrual cycle.

​Towards the end of your menstrual cycle, the blood gets discolored especially if your flow is very slow,

​If the blood passing from the uterus into the vagina is not quick enough, it becomes deoxygenated.  This makes the color of the blood to become black or dark brown.                                                                                                                              

Dark brown blood at the beginning and at the end of your period is usually nothing to worry about.

3. ​Hormonal Imbalance

The color of your period can provide clues to what is going on in your body especially your hormonal health.

A black or dark blood during period can be a sign that you have high levels of estrogen hormone. Estrogen is the hormone that is responsible for thickening the uterus lining.

If your period contains large blood clot, it may be caused by serious hormonal imbalance problems.

4. Birth control (iud, depo provera, nexplanon)

Birth control pills contain artificial hormones that disrupts the natural balance of hormones in the body.

One of the side effects of mirena is brownish or black period and discharge. Mirena is an hormonal intrauterine device that is inserted into the uterus.

Some women who use mirena and other contraceptive pills, birth control implants(nexplanon) or even depo provera shots have complained about seeing black vaginal discharge or black blood.

Other side effects of hormonal birth controls are spotting or bleeding between periods.

5. Blood Clots

It is normal to see dime sized blood clot in your period from time to time. The color of the blood cloth can range from bright red to black or dark brown.

Blood clots are common during heavy periods. Your body releases anticoagulants to thin blood during menstruation.

But blood clots are formed when you have a heavy flow of blood that is expelled quickly giving no room to the anticoagulants to work.

A larger than a quarter blood clot is a sign of a serious underlaying condition.

See a doctor immediately if this happens to you.

5. Pregnancy

One of the first signs of pregnancy is implantation bleeding or spotting.

It happens around a week before your expected period.

Implantation bleeding is usually pink or red in color but in some cases it is brown or black in color which signifies old blood that occurred during the implantation process.​

Implantation bleeding only lasts for a few hours and the blood is scanty not a normal period flow.

If you are pregnant and you notice an abnormal vaginal discharge or bleeding, see the doctor immediately. 

6. ​ Miscarriage

A miscarriage is the loss of pregnancy within the first 24 weeks. A miscarriage than happens before the first 12 weeks is known as early miscarriage.

A​ miscarriage that happens between week 12 and week 24 is known as a late miscarriage.

One of the common causes of black blood with tissues is a miscarriage.

Because most miscarriages occur before week 4 of pregnancy, most women are not even aware they were pregnant until they see an abnormal period with large blood clot and tissues. 

After a miscarriage some blood could also be retained in the uterus. This retained blood is expelled at a later date as black or old blood.

7. uterine fibroid

Uterine fibroids are non-cancerous tumors that grows on the walls of the uterus. The exact cause of uterine fibroid is unknown. But genetics and hormones levels play a huge role in why fibroids grow or shrink.

Most women with fibroids do not know that they have it. One of the common symptom of fibroid is heavy period.

Fibroids obstructs the normal flow of blood. It also makes the womb to grow bigger.

When the normal flow is obstructed, blood is retained back in the uterus.

8. Endometriosis

Endometriosis is a condition in which the tissues that line the uterus(womb) are found in the fallopian tubes, ovaries and pelvis.

Endometriosis causes cramping and pain in the lower abdomen.​

The symptoms of endometriosis are abnormal vaginal bleeding and brown spotting between periods. 

Endometriosis is also known as chocolate cyst because of the dark brown or blackish blood it produces. 

9. Polyps​

Uterine polyps occurs when cells overgrow in the lining of the uterus. uterine polyps is also known as endometrium polyps.

The symptoms of polyps include irregular menstrual bleeding, excessive menstrual bleeding and bleeding after menopause.

What to do about Dark Period Blood

If you have an abnormal menstrual bleeding, see the doctor immediately to investigate further.

A normal period is usually bright red in color with small sized clots.​

A dark brown or almost black color of blood is not a problem at the beginning or at the end of period. ​

Frequently asked Question

what does Black stringy Period Blood at the beginning of period mean?

"Why is my menstrual blood brown on the first day"

Dark blood at the beginning of period is common. It is the way the uterus gets rid of old blood that  it didn't expel in the previous cycle.

Your period should be back to normal red after 1 -2days of black period spotting or flow.

Black Blood Before Period

Black blood a few days before period is a sign of pregnancy or it could be caused by an infection or disease.

Black menstrual Blood On the Pill

Thick black blood is a common side effects of women who use any form of hormonal contraceptive.

Most women get abnormal looking period at some point in their lives.​

Black vaginal discharge with IUD 

IUD are used to prevent pregnancy. They are small coils often T shaped placed in the uterus.

The side effect of IUD is that it increases bleeding during menstruation. It also causes  black discharge after period.

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