Black Period Blood and Discharge Before, After, and At the Beginning of Period: Causes and When to Be Concerned

black period blood may be normal

Black period blood is normal but it may also be a sign of a health problem. It may or may not be accompanied by clots. When experienced, it usually occurs on lighter days at the end of the period. It is, however, possible to experience brown or black period blood at the beginning of your period or throughout the “cycle”. You can also experience dark menstrual blood or discharge in between periods when factors such as botched pregnancy are involved. This article investigates the reasons why your period blood may look black.

Why Is My Period Blood Black?

I googled, “why is my period blood black?” after spotting that in my pad and one of the resources pointed to cancer as a possible cause. I was devastated.

I got a sigh of relief when I learned that although uterine and cervical cancer can actually cause brown or black bleeding, it is not a common cause of the problem. Also, the bleeding is usually not confined to menstrual periods. It can also occur in between your periods.

The typically red to dark red menstrual blood may turn brown or black for the following reasons:

  • Loss of the oxygen bound to hemoglobin. Red blood cells contain a protein called hemoglobin to which oxygen binds. When blood leaks out of the normal circulation (blood vessels) and gets exposed to air, hemoglobin progressively loses its bonded oxygen. This causes the blood to turn dark red or even black when oxygen levels fall too low.
  • Exposure to certain chemicals. Some chemicals (including some birth control hormones) can also cause fast degradation and thus discoloration of red blood cells. This can then make your period blood turn black or brown by the time it flows out.
  • Degradation by bacterial enzymes. Bacterial infections can also manifest themselves in unusually-black period blood.

Causes of Black Period Blood

If your period blood looks black, then here are some of the possible reasons you need to be aware of. You may want to speak to your healthcare provider to rule these out:

1. Old or Delayed Period Blood

It is not uncommon to notice brown to black period blood towards the end of the period (say 4 days after the period begins for example). During this time, the flow is usually light. The WebMD says this is normal and not a cause for concern.

It is usually the result of menstrual blood that has been delayed in the body. As the blood gets older inside the body, it changes color from dark red to brown or black before it finally expelled from the body.

2. Birth Control Pills and Devices

Some women experience unusually-black period blood shortly after getting on the pill (contraceptive pills such as Mirena) or switching to a new birth control product. Cases have been reported with Depo-Provera injections, implants such as Nexplanon and Implanon, and IUD devices.

birth control pills

Morning after pills (emergency contraceptive pills) such as Plan B have also been implicated.

There are also women who experience brown to black period blood after stopping birth control.

According to O’Shea Molly, MD, a pediatrician based in Troy, Michigan, when you start a new birth control, hormonal changes occur in the body. Consequently, the lining of the uterus may not thicken as much as it normally does.

The rate at which a new pill or contraceptive device releases its hormones may be different from that of your previous birth control method. These factors can cause the uterine lining to slough off (shed) more slowly. This, in turn, makes menstrual blood to take longer to exit the body through the vagina. Thick, black period blood is often a manifestation of this.

Depending on their reaction to the hormones used, some women may actually never get the normal red menstrual blood when using certain pills, says Dr. Molly.

“Some women may actually never get the normal red menstrual blood when using certain pills.” – Dr. Molly

3. Pregnancy

I see the question “my period blood looks black, does it mean that I am pregnant?” relatively often. Black period blood can indeed be an early sign of pregnancy. It is often an indication of implantation bleeding.

pregnant woman

According to The American Pregnancy Association, implantation bleeding occurs when the fertilized egg attaches to the lining of the uterus. It takes place 6 to 12 days after conception.

Implantation bleeding is usually more of a spotting (few drops of blood in the underwear or pad) than actual bleeding (characterized by heavier blood flow).

Women who are not yet aware that they are pregnant may mistake implantation bleeding for an impending menstrual period.

The blood associated with implantation bleeding typically delays in the uterus before flowing out of the body which makes it range in color from dark brown to black. In some cases, however, the blood may come out more fresh (usually pink, but rarely bright red) and look more like normal menstrual blood.

If the perceived “black period blood” is actually a case of implantation bleeding, the spotting will continue over the course of 1 to 3 days. It usually will be accompanied by other symptoms of pregnancy such as cramps, lower back pain, nausea (morning sickness), headaches, bloating, and fatigue.

4. Miscarriage

Brown to black period blood just before the period or in between periods (when you don’t expect your periods) may be a sign of miscarriage.

Some women get pregnant and fail to notice it until they get a miscarriage.

If you are pregnant, see your doctor or health care provider immediately if you notice any vaginal bleeding, more so if it is accompanied by abdominal pain or laden with clots or tissues. These are usually the remnants of conception that are being ejected from the body.

In some cases, these remnants get retained in the uterus, a phenomenon known as missed abortion. This happens when the cervical os (the opening into the cervix from the uterus) doesn’t dilate enough to let the products of conception through. This later causes brown to black, foul-smelling vaginal discharge.

5. Female Genital Tract Infections

female reproductive system

Black blood that is not period (in between periods) can also be a sign of infections involving the female genital tract (pelvic inflammatory disease). The same is true of black period blood that occurs at the beginning of period or throughout the “cycle”. The darkening of the blood is attributed to rapid degradation of blood by the proteolytic enzymes produced by bacteria involved.

Endometritis is the most common culprit. This refers to inflammation of the lining of the uterus as a result of an infection. It is usually attributed to tuberculosis and sexually transmitted infections such as chlamydia and gonorrhea. The normally harmless vaginal bacteria can also overgrow and cause a condition known as bacterial vaginosis (BV) which often culminate in endometritis.

Endometritis is seen more commonly after childbirth or miscarriage, with C-section delivery and long labor being the main predisposing factors.

Cervix infection can also make period blood to turn brown or black as well as cause bleeding in between periods.

Other Causes of Black Period Blood and Vaginal Discharge:

  • Foreign object in the vagina. This could be a piece of a tampon or ruptured condom. Such objects can in addition cause vaginal discomfort and make the discharge have a foul smell.

Treatment of Period Blood That Looks Black and Vaginal Bleeding Between Periods

Stethoscope - Regular black period blood requires medical attention

As already mentioned, black period blood at the end of the period is normal and no reason to get worried, unless of course it occurs so frequently or is associated with particularly heavy bleeding.

If black discharge or blood is however experienced before period or at the beginning of the period (e.g. on the first day), or a few days or weeks after the period, it warrants the attention of your doctor or a gynecologist. The same is also true of vaginal bleeding that occurs after menopause.

Your doctor will make the proper diagnosis and help rule out serious underlying causes such as cancer.



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