Why Is My Discharge Black? 9 Causes of Black Discharge

Nothing rings alarm bells more than seeing unusual vaginal discharge, but it isn’t always a cause for concern. Menstrual blood can be a range of colors, and while some are alarming, most are completely normal.  

In this post, we’ll explore black discharge, including the potential causes and when you should seek out medical help.     

Is black discharge normal?

Black discharge is usually the result of blood that has taken extra time to exit the uterus and while it may be alarming, black is a normal color that you might see throughout your cycle.  Because the blood has been in the body for longer it has had time to oxidize, which naturally darkens the color. 

What does the color of your period blood mean? 

The flow of blood from the vagina is a mixture of both blood and tissue from the lining of the uterus and can be affected by a variety of factors.  Hormonal activity, the intensity of menstrual bleeding, infection, age of blood, and even a person’s diet can all cause variations in the color of period blood.  

Changes in flow over the course of your cycle can cause period blood to vary from bright red to dark brown. In general, bright red blood is expected at the beginning of your period when the uterine lining is being shed at a rapid pace and the discharge doesn’t have a chance to oxidize.

In some cases, the color of your period blood may indicate an issue.  If you have any concerns about your flow or have noticeable changes, it’s best to seek advice from a doctor.  

What are possible causes of black discharge or period blood?

Before a period 

You may see black spotting or dark discharge before your period starts.  Blood left over from your last period may still be in your body and has had a chance to oxidize, turning it darker in color.  Your vagina is simply cleaning itself out  and the menstrual flow can also be slightly slower at the beginning of a period, giving old and new blood a chance to oxidize as it slowly leaves the body.  

After a period 

As your period ends, blood flow will begin to slow down again and the blood in your uterus may take longer to leave the body.  During this process the blood will change from the standard bright red to a dark brown or black as it is exposed to oxygen and becomes oxidized.  The longer it takes for the blood to leave your body, the more time it has to turn darker.  

Something stuck in the vagina 

Black discharge or blood can be a sign that there is a foreign object in the vagina.  The most common culprit is a forgotten tampon (or accidentally putting in a second tampon) but other objects can get stuck as well.  Sex toys, condoms, and contraceptive devices like sponges, rings, or diaphragms can all get lodged in the vagina. 

Over time, irritation of the vaginal lining can trigger an infection that along with black blood, could also be accompanied by smelly discharge, discomfort or itching, rash, fever, difficulty urinating, and pelvic or abdominal pain.  If your black period blood is accompanied by any of these symptoms you should seek medical attention immediately.  In rare instances, it could lead to an infection that is life-threatening, like toxic shock syndrome. 

Retained period blood 

When menstrual blood can’t leave the body for whatever reason it is a condition known as hematocolpos.  Also known as retained menses, the blood fills the vaginal canal and vagina and grows darker as it oxidizes over time.  This is usually due to a congenital issue with the pelvic anatomy and is diagnosed during adolescence, but it can also occur as a result of surgical complication.     

Pelvic Inflammatory Disease (PID)  

Sexually transmitted infections (STI), especially gonorrhea and chlamydia, may come with a host of symptoms like unpleasant discharge, pain, burning while urinating, itching, and even black discharge.  Left untreated, the infection is able to spread from the cervix and vagina to the upper genital tract where it is known as Pelvic Inflammatory Disease (PID).  

Unusual bleeding or black vaginal discharge along with a foul odor is usually a symptom of infection and you should seek treatment.  Without proper treatment, most women will go on to develop PID, a leading cause of infertility that can make getting pregnant much more difficult.   

Implantation

Some women experience light bleeding or spotting during the implantation process.  If the blood produced during this process takes some time to leave the vagina, it may be darker in color and look black.  Not all women experience this type of bleeding but if it is also accompanied by symptoms of early pregnancy or if it develops into a heavy flow, see a doctor.    

Lochia 

Postpartum bleeding is a type of discharge that is similar to your menstrual period and known as lochia.  Although it is similar to a menstrual period, this bleed typically lasts four to six weeks and contains blood, pieces of the uterine lining, mucus, and white blood cells.  The flow starts out heavy and red but changes to pink or brown as time passes.  If the blood is especially slow, it may even turn dark brown or black.        

Miscarriage

Black bleeding or discharge may be a sign of miscarriage, a fate for 10 to 20 percent of known pregnancies.  There may not be any other signs of miscarriage, in which case the black discharge may indicate a silent or missed miscarriage.  In these cases, the baby has stopped developing in the womb but the body has not yet recognized the loss of pregnancy and the pregnancy tissues have not been physically miscarried.          

Cervical cancer (in rare cases)  

In very rare instances, black period blood or black discharge may be a sign of cervical cancer.  If it is combined with other signs such as irregular bleeding after sex or between periods, it may be a warning of cervical cancer.  In the more advanced stages of cervical cancer other symptoms include weight loss, fatigue, pelvic pain, swelling in your legs, and difficulty urinating and passing bowel movements.  

How to treat black discharge

When black discharge is part of your normal menstrual cycle or vaginal discharge there’s nothing you need to do for treatment.  However, if you have concerns, or it is accompanied by other symptoms, it’s best to see a doctor.  

Treatment options will be dictated by what’s causing the black discharge to occur in the first place.  For example, a foreign object stuck in the vagina will require a different treatment plan than one for a miscarriage or cervical cancer.  Medical assistance runs the gamut from antibiotics to treat an infection to surgery to remove a blockage and will be developed by your healthcare provider.  

When to see a doctor

If black discharge or black period blood is not normal for you, it might point to a serious underlying issue though and it’s important to consult a doctor.  If your black discharge is also accompanied by any of the following symptoms, seek medical attention:

• Foul-smelling discharge
• Vaginal discomfort
• Heavy discharge
• Cramping, pain, fever

The average menstrual cycle lasts anywhere between 21 to 35 days and can vary from month to month and woman to woman.  Black discharge or bleeding outside of your “regular” time frame should be discussed with your doctor.  Tracking your menstrual cycle and learning your patterns can help you with this.   

Black discharge and period blood FAQ

Winding down

It can be alarming to see black discharge but it isn’t always a cause for concern.  If your bleeding is unexpected, or you’ve recently delivered a baby and you see black blood you should seek medical attention.  Likewise, if black discharge is accompanied by other symptoms such as fever, chills, or cramping you should also see a doctor.  Otherwise, black discharge can be a normal occurrence in your menstrual cycle.