Dark Period Blood: 6 Causes & When to See the Doctor

Endometriosis is the growth of endometrial tissue outside the uterus. This type of problem, or other conditions like adenomyosis, can cause severe pain in the pelvic region and dark discharge, similar to coffee grounds, that can occur both during and between menstruation.

What to Know About the Color of Period Blood

Young women who have just started their periods often worry about changes in the color of their period blood. They want to know whether it’s OK for blood to be brown and not red.

‌It’s considered normal for blood to vary between shades of red and brown during the first few years after menarche, or when you start having your periods. Even in later years, or as an adult, such color changes are considered normal. The color of period blood can change during the same period cycle as well. For example, it can start out bright red in the beginning and change to a rusty brown at the end of the cycle. It can even start as brown in the beginning and turn redder towards the end of your period.

Why Does Period Blood Have Different Colors?

‌The color of blood becomes darker the longer it stays inside your uterus and vagina because it starts to react with oxygen. The reaction causes the color to get darker. The longer the blood stays inside your body, the darker it gets.

Normal Colors Seen in Period Blood

It’s normal to see period blood in shades of pink, red, and brown. The shades can mean different things.

• Pink blood: Pink blood is often seen at the time your period starts. At this stage, some of the fresh, bright red blood may mix with vaginal discharge causing the color to lighten and look pink. Vaginal discharge is a mix of fluid and cells shed by your vagina to keep your vaginal tissues healthy, moist, and free from infection or irritation. If your periods are light, the blood may also appear pink.
• ‌Bright red blood: As your uterus starts to actively shed blood during your period, you may notice that the color is bright red. This just means that your blood is fresh and has not been in the uterus or vagina for some time.
• Dark red blood: Dark red blood is simply blood that has been in the vagina for longer. It can even be seen with blood clots. Clotting is also considered normal unless the clots are larger than the size of quarters.
• Brown or black blood: These are color variations seen in blood that has taken longer to exit the vagina. Black blood can be dark red or brown-colored blood that appears black. Sometimes, as your period comes to an end, the dark blood can mix with vaginal discharge and end up looking brown.

When to Consult Your Doctor

‌It’s normal to see period blood in pink, red, and brown colors. Consult your doctor if you have any questions or concerns about color changes in your period blood or if you experience unusual changes in your cycle.

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Also, consult your doctor if you experience any of the following:

• ‌Periods that last longer than seven days or if you need to change pads and tampons every one to two hours.
• Severe cramping during your menstrual cycle.
• ‌You experience dizziness or you feel lightheaded, weak, or tired.
• ‌You have chest pain or trouble breathing during or after your period.
• ‌Your menstrual blood contains clots larger than the size of quarters.
• You have spotting or bleeding anytime in the menstrual cycle other than during your period.
• Your period cycles are shorter than 24 days or longer than 38 days.
• ‌You haven’t had a period in three months and you’re not pregnant or breastfeeding.
• Your normal cycles have changed and they’re now irregular.
• ‌You haven’t had your first period by age 15.
• ‌You’re still bleeding after menopause, which is when your menstrual cycle comes to an end. Menopause usually takes place in your 40s or 50s.
• ‌Your vaginal discharge looks abnormal or smells unusually bad.
• You experience high fevers with your periods.
• ‌You experience nausea or vomiting with your periods.

Diagnosis of Period Problems

‌Your doctor will review your medical history and medications and conduct a physical examination to identify the causes of abnormal periods. The physical examination may include a pelvic exam as well as a pap test. Other tests your doctor may order include:

• ‌Blood tests to check if you have anemia or other medical conditions
• Vaginal cultures to check for possible infections
• ‌A pelvic ultrasound to check for fibroids (abnormal growths in the uterus), polyps (growths seen in the inner lining of the uterus called the endometrium), or cysts (abnormal and sometimes painful growths filled with a liquid or semisolid substance).
• ‌An endometrial biopsy where a small sample of tissue is taken from the lining of the uterus and is examined under a microscope to check for cancer or other cell abnormalities.

‌Your doctor will recommend the right course of treatment based on the cause of your abnormal periods.

Show Sources

Cleveland Clinic: “Abnormal Menstruation (Periods),” “Endometrial Biopsy,” “What Does the Color of Your Period Mean?”

Mayo Clinic: “Menopause,” “Vaginal discharge.”

MedicineNet: “Medical Definition of Menarche.”

OASH: “Period problems.”

TeensHealth: “Is Period Blood Always Red?”

Dark Period Blood: 6 Causes & When to See the Doctor

Generally, small quantities of dark blood during a period is normal and does not indicate any health problems. especially if it occurs at the beginning or end of a period. However, it occurs frequently, it can be a sign of hormonal changes, uterine problems, stress or a sexually transmitted infection.

This can also happen when taking a birth control pill for the first time, when birth control is changed, or if the morning-after pill is taken. In these cases, menstruation can also become darker or have a coffee ground texture, but it usually returns to normal by the next cycle.

If the color of your period blood changes from its norm, or if it you have any concerns about how it looks, you should consult your family doctor or gynecologist. They can assess for any abnormalities and intiate treatment as necessary.

Main causes of dark period blood

Menstruation blood which is black, brown, or similar to coffee grounds may be caused by:

1. Pregnancy

A small amount of pink, brown or dark red bleeding is common in the first weeks of pregnancy as the embryo attaches to the walls of the uterus.

However, when this bleeding occurs at a later stage of pregnancy or is accompanied by other symptoms such as abdominal pain, shoulder pain, dizziness or excessive fatigue, it may indicate an ectopic pregnancy or miscarriage. You should be assessed immediately if you have any of these symptoms to rule out any problems.

2. Emotional changes

Some changes in a woman’s emotional state, such as increased stress or depression, can affect the structure of the uterus by reducing the thickness of its walls. This change delays shedding of the uterine lining in preparation for menstruation, and blood has more time to become oxidized making it darker in color.

3. Hormonal changes

4. Sexually transmitted infections

Sexually transmitted infections caused by bacteria, such as gonorrhea or chlamydia, cause a more rapid breakdown of menstrual blood, which makes it darker. This type of blood is usually also accompanied by a foul smell, brown discharge before or after menstruation, pelvic pain and a fever above 38º C.

5. Endometriosis and other conditions

Endometriosis is the growth of endometrial tissue outside the uterus. This type of problem, or other conditions like adenomyosis, can cause severe pain in the pelvic region and dark discharge, similar to coffee grounds, that can occur both during and between menstruation.

In these cases, the period, besides being dark, can also last up to 7 days. In case of suspicion, you should go to the gynecologist for assessment and treatment as necessary (which may include surgery).

6. Post-partum

During the post-partum stage, dark blood is also an expected, normal finding. The uterus takes about 45 days to return to its normal size and bleeding typically happens during this time. This bleeding isn’t exactly menstruation, but it can be dark in color, and may confuse many women.

When should you go to the doctor?

Changes in menstrual bleeding are usually normal and do not indicate problems, but you should go to the gynecologist if you have other symptoms, such as:

• Period lasting more than 7 days
• No period for more than 3 months
• Vaginal bleeding between periods
• Vaginal pain
• Fever above 38º C or 100.4º F
• Dizziness
• Pale skin throughout the body or below the nails.

It is also important to remember that in cases of suspected pregnancy, the appearance of dark bleeding, with clots or in large quantities, is also a reason to see the doctor, because it may be a miscarriage, and a curettage may be necessary to clean the uterus.

Edited by Tua Saude editing team in May 2022. Medical review completed by Dr. Sheila Sedicias – Gynecologist in November 2018.

What does the color of period blood mean?

The color of a person’s period blood can relay vital health information. For example, orange or grey blood can sometimes indicate a vaginal infection.

During menstruation, the body sheds tissue and blood from the uterus through the vagina. This bloody discharge can vary from bright red to dark brown or black depending on how old it is.

Blood that stays in the uterus long enough will react with oxygen (oxidize). Blood that has had time to oxidize appears darker.

Hormonal changes and health conditions can also affect the color and texture of period blood.

In this article, we present a period blood chart and discuss what the different colors of period blood can mean. We also cover color changes during a period, what clots mean, and when to see a doctor.

Black blood can appear at the beginning or end of a person’s period. The color is typically a sign of old blood or blood that has taken longer to leave the uterus and has had time to oxidize, first turning brown or dark red and then eventually becoming black.

Black blood can sometimes also indicate a blockage inside a person’s vagina. Other symptoms of a vaginal blockage can include:

• foul-smelling discharge
• fever
• difficulty urinating
• itching or swelling in or around the vagina

Like black blood, brown or dark red is a sign of old blood, and it may appear at the beginning or end of a period. Brown or dark red blood has not had as long to oxidize as black blood and can appear in a variety of shades.

Pregnancy

Brown blood or spotting can sometimes also be an early sign of pregnancy that doctors refer to as implantation bleeding.

Brown discharge or spotting during pregnancy can indicate a miscarriage or an ectopic pregnancy, which is when the fertilized egg implants in a fallopian tube instead of the uterus.

It is important for women who experience spotting or vaginal bleeding during pregnancy to speak to their doctor or obstetrician.

Lochia

Dark red or brown vaginal discharge that occurs after giving birth is called lochia, or postpartum bleeding. Lochia is not a cause for concern and is the body’s way of expelling excess blood and tissue from the uterus.

Lochia typically begins with bright red blood and then transitions to a darker shade as the flow decreases. Over time, the discharge will then become lighter in both color and amount.

The duration of lochia varies from person to person, but it usually passes within the first few months after delivery. Women who experience very heavy bleeding after giving birth should see a doctor.

Not all women experience lochia after giving birth. Women may also experience irregular periods after giving birth due to changes in hormone levels.

Bright red blood indicates fresh blood and a steady flow. A period may start with bright red bleeding and darken towards the end of the period. Some people may find that their blood stays bright red throughout their period.

Unusual spotting or bleeding between menstrual cycles may be a sign of a sexually transmitted infection, such as chlamydia or gonorrhea. Growths in the uterine lining, called polyps or fibroids, can also cause unusually heavy bleeding.

Rarely, bright red bleeding may be a sign of cervical cancer. Other symptoms of cervical cancer include:

• heavier periods
• periods that last longer than normal
• bleeding after sexual intercourse
• foul-smelling vaginal discharge
• pain in the lower back, pelvis, or legs
• loss of appetite
• unexplained weight loss

Pink blood or spotting can occur when period blood mixes with cervical fluid.

Using hormonal birth control can lower estrogen levels in the body, which can lead to a lighter flow with a pinkish hue during periods.

Sexual intercourse can create small tears in the vagina or the cervix. Blood from these tears can mix with vaginal fluids and exit a person’s body as pink discharge.

Other causes of pink period blood can include:

• significant weight loss
• unhealthful diet
• anemia

Pregnancy

During pregnancy, pink discharge that contains tissue and occurs alongside cramps may indicate a miscarriage. It is important for women who experience vaginal bleeding while pregnant to see their doctor or obstetrician.

Blood that mixes with cervical fluid can also appear orange.

Orange blood or discharge often indicates an infection, such as bacterial vaginosis or trichomoniasis. People with orange blood should check for other telltale symptoms, such as vaginal itching, discomfort, and foul-smelling discharge.

Although orange period blood or discharge does not always indicate an infection, it is a good idea for a person to see a doctor or gynecologist for an evaluation.

Gray discharge is usually a sign of bacterial vaginosis, a condition that occurs due to an imbalance between beneficial and harmful bacteria in the vagina.

Other symptoms of bacterial vaginosis include:

• itching in and around the vagina
• foul-smelling vaginal odor that people often describe as “fishy”
• burning or painful urination

People with symptoms of bacterial vaginosis should see a doctor or gynecologist. Doctors usually prescribe antibiotics to treat bacterial vaginosis.

Pregnancy

During the later stages of pregnancy, gray discharge containing clots can indicate a miscarriage. Women who experience bleeding during pregnancy should see their doctor or obstetrician.

Blood can change in color and texture from month to month or even during a single period.

Hormonal changes, as well as a person’s diet, lifestyle, age, and environment, can all cause variations in period blood.

Period blood can vary from bright red to dark brown according to changes in flow. Infections, pregnancy, and, in rare cases, cervical cancer, can cause unusual blood color or irregular bleeding.

People who experience unusually long or heavy periods may require an appointment with a doctor.

Share on Pinterest A person should see a doctor if they have bleeding that requires a tampon or pad change after less than 2 hours.

Healthy period blood can contain visible pieces of the uterine lining. These small pieces of tissue, or clots, in the blood are not a cause for concern.

However, very heavy bleeding or large clots can be a sign of menorrhagia. According to the Centers for Disease Control and Prevention (CDC) , menorrhagia is when a person has unusually heavy menstrual bleeding or periods that last for more than 7 days.

The CDC recommend seeing a doctor if a person has one of the following:

• bleeding that requires a person to change a tampon or pad after less than 2 hours
• blood with clots that are the size of a quarter or bigger

The CDC also list the following as causes of menorrhagia:

• growths on the uterus, such as uterine fibroids or polyps
• hormonal imbalances
• pelvic inflammatory disease
• intrauterine birth control devices (IUD)
• bleeding disorders, such as von Willebrand disease
• certain medications, such as aspirin and anticoagulants
• cervical or uterine cancer

Without treatment, menorrhagia can lead to complications, such as anemia or chronic fatigue.

It is advisable for people to consult a doctor or gynecologist for any of the following symptoms:

• new or unusual vaginal discharge
• irregular periods that change in length and flow from one month to the next
• bleeding after menopause
• missing three or more periods
• foul-smelling vaginal odor
• thick gray or white vaginal discharge
• itching in or around the vagina
• fever

Anyone who is pregnant and notices any bleeding or unusual vaginal discharge should speak with their doctor or obstetrician.

The color and consistency of period blood can provide useful information about a person’s overall health.

However, everyone’s period is different, and blood can change color and consistency during a period and from month to month. So it essential for people to learn what is normal for them.

Healthy period blood typically varies from bright red to dark brown or black. Blood or discharge that is orange or grey may indicate an infection. Women who experience bleeding during pregnancy should see a doctor or obstetrician for an evaluation.

Last medically reviewed on April 1, 2019

• Infectious Diseases / Bacteria / Viruses
• Pregnancy / Obstetrics
• Women’s Health / Gynecology
• Cat 1
• vaginalhealth

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