What to Know About the Color of Period Blood

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

What Does the Color of Your Period Mean?

Your period — it comes, it goes. It’s light, it’s heavy. But have you noticed it sometimes changes color — from crimson red to light pink to brown? What’s that all about? Ob/Gyn Swapna Kollikonda, MD, offers a color-coded guide to period blood.

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Why period blood has different colors

“The color of period blood depends on how long the blood stays in the uterus and vagina,” says Dr. Kollikonda. “The longer it sits, the darker it gets because the blood oxidizes — it reacts with oxygen in your body and gets darker.”

Period blood commonly takes on these different colors:

Pink period

When a period starts, your vaginal mucus discharge may mix with some fresh, bright red blood, which then gets diluted. What’s shed is blood with a pink hue. Lighter periods may also appear more pink than red.

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Bright red period

As your uterus actively contracts, it sheds blood quickly. Since the blood doesn’t have time to oxidize, it remains a vibrant red.

Dark red period

If you have a moderate period, it may take longer for the uterus to shed the lining. As it sits in the uterus, it gets darker.

Dark red + blood clots

If your uterus doesn’t contract well and sheds blood quickly, it can cause blood to stay in the uterus and clump together, forming clots. Clots can be tiny or big, but they are usually a deep red color.

Brown period

As your period ends, you might experience a lighter blood color, which then mixes with vaginal mucus discharge.

When to worry about the color of your period blood

“Ob/gyns are rarely concerned about the different colors of period blood,” says Dr. Kollikonda. “If you have spotting between your period or post-menopausal bleeding or a heavy flow or lighter flow, that’s when we want to investigate.”

She also wants to know if you:

• Often experience quarter-sized or larger blood clots.
• Are soaking a pad every hour, plus passing blood clots.
• Too frequent or infrequent periods.
• Prolonged bleeding for days during periods.
• Bleeding for a month at a time.
• Severe cramping during periods.

Dr. Kollikonda says color, consistency and amount are subjective. If you find it worrisome, then it’s worth reaching out to your provider. Most likely, you’ll get reassurance that what you are experiencing is normal.

Diagnosing period problems

To rule out problems, your ob/gyn will discuss medications you are taking. Drug interactions with birth control pills or not taking them correctly can also can also cause irregular periods.

Next, you will probably have a transvaginal ultrasound. During this painless procedure, your provider inserts an ultrasound probe into your vagina. The probe emits soundwaves that create detailed pictures on a screen.

“We use the pictures to help diagnose endometrial growths (polyps), fibroids or adenomyosis (when the uterine lining (endometrium) grows into the wall of the uterus),” says Dr. Kollikonda. “All these issues might impact how your uterus contracts and can cause clots or irregular bleeding or excessive bleeding.”

Depending on the findings, your doctor may want to run additional tests before figuring out how to best care for you.

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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.

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?”