Seeing black menstrual blood in your underwear or on your pad can be a little alarming. Your brain might immediately go, Wait, is that normal? The good news is, in most cases, it is.
Menstrual blood can range in color from bright red to deep brown or even black, and the shade often just reflects how long it’s been in your uterus before making its exit. Still, it’s understandable to have questions — because your period can tell you a lot about what’s going on inside your body. Here’s what black period blood really means, when it’s totally normal, and when it’s worth checking in with your doctor.
What does black menstrual blood mean?
For starters, black menstrual blood is usually totally normal. It tends to happen towards the beginning and end of your menstrual period. You may notice that your blood is a darker color, from brown to black, instead of the bright red that generally occurs during the middle of your period. This is simply what happens to blood when it’s exposed to oxygen and the atmosphere — it tends to lose some of its bright redness and appear darker.
Why is my menstrual blood black?
When blood is exposed to oxygen, it oxidizes, causing it to turn a darker color. This happens with all blood, think of maybe a time you got a cut, and when the blood dried, it was no longer bright red, but darker brown or black.
According to OB/GYN Dr. Rachel Miller, toward the beginning and end of your menstrual period, the blood is older. It’s been sitting in your uterus for longer before coming out, and has already been exposed to oxygen, causing it to appear darker.
Is black menstrual blood normal?
Yes — most of the time, black menstrual blood is totally normal. Many women tend to notice darker-colored menstrual blood, particularly on the front and back end of their menstrual periods.
Sometimes, though, it could be a sign of something else, such as infection or fibroids. When it’s accompanied by symptoms such as fever, foul odor, or pelvic pain, it is a good idea to schedule an appointment with your doctor for a work-up to make sure nothing more serious is going on.
Black blood from menstrual period: When it can happen
So, when exactly does black blood from your menstrual period show up? The short answer: it can happen at a few different points in your cycle — and not always for the same reason.
But understanding when it happens (and what else is going on with your body at the time) can help you tell the difference between what’s normal and what’s worth a quick chat with your doctor.
Black blood at beginning of menstrual period
Questions Women Are Asking
At the beginning of your period, the uterus sheds its lining at a slower pace. As a result, the blood that comes out has generally been sitting in the uterus for some time before exiting the body, giving it time to oxidize and darken. This is completely normal, and something many women will notice especially at the beginning of their period.
Black menstrual blood causes
When it comes to black menstrual blood, timing isn’t the only factor — sometimes, the cause matters too. While darker blood is often just older flow making its way out, certain health conditions or hormonal changes can also play a role.
There are a few different reasons you might notice this color change. Understanding these possible causes can help you figure out what’s normal for you — and when it’s time to get things checked out.
Black menstrual blood and fibroids
Sometimes, if your menstrual blood appears black and you’re also dealing with pelvic pain, heavier periods, or pressure in your lower abdomen, uterine fibroids could be part of the picture. These are non-cancerous growths that develop in or around the uterus — and while they’re incredibly common, they can sometimes make periods more intense or unpredictable. Dr. Miller explains that fibroids can slow the flow of blood, giving it more time to oxidize and darken before it leaves the body. Most fibroids are harmless and can be managed with monitoring or treatment if needed, but if your symptoms are new, worsening, or affecting your quality of life, it’s a good idea to check in with your OB/GYN to talk through options and find some relief.
Black menstrual blood with an IUD
Whether or not you have an IUD, it’s totally normal to see darker blood from time to time — often it’s just older blood taking its time to leave the body. But if you do have an IUD, especially a hormonal one, you might notice more spotting or irregular bleeding during the first few months as your uterus adjusts. This can happen because an IUD thins the uterine lining, which can lead to lighter, slower bleeding. When that blood lingers a bit longer before exiting, it oxidizes and turns brown or black. It can look a little strange, but in most cases, it’s nothing to worry about. If the spotting continues past the adjustment period, or if you’re experiencing pain or other changes, it’s worth chatting with your OB/GYN to make sure everything’s settling in as it should.
Black menstrual blood during pregnancy
According to Dr. Miller, any type of bleeding during pregnancy — even a small amount — is something to mention to your doctor. The color doesn’t necessarily point to a miscarriage; in many cases, light bleeding can be linked to harmless things like cervical changes or implantation. That said, black or dark brown blood during pregnancy can indicate older blood slowly leaving the uterus, so it’s always best to have it checked just to be safe. Every pregnancy is different, and only your OB/GYN can determine what’s normal for you. Reaching out early can offer peace of mind — and make sure you and your baby are both well cared for.
Black menstrual blood after menopause
After menopause, your periods have officially stopped — so any new bleeding, even a tiny amount, is worth investigating. That includes black or brown discharge, which might be older blood that’s taken longer to leave the uterus. While it’s not always something serious, Dr. Miller stresses that postmenopausal bleeding should never be ignored. It could be linked to something as simple as hormone changes or vaginal dryness, but it can also signal more concerning conditions like polyps, fibroids, or, in rare cases, endometrial cancer. Getting checked by your OB/GYN helps pinpoint the cause quickly and ensures you get the right care and reassurance you need.
Types and characteristics of black period blood
Not all black period blood looks or feels the same. Sometimes it’s thick and clotted, other times it’s sticky or tar-like, and occasionally it shows up in small streaks rather than full flow. These differences can offer clues about where you are in your cycle and how your body is shedding the uterine lining. Let’s break down the most common types and textures of black menstrual blood, and what each one can mean.
Black menstrual blood clots
Menstrual clots are completely normal — they’re simply a mix of blood and uterine tissue that your body releases during your period. These clumps can vary in size and color, often appearing darker when the blood is older. According to Dr. Miller, this usually isn’t a cause for concern. However, if you notice a very large, black clot (like the size of a golf ball), it’s best to check in with your OB/GYN to rule out anything more serious.
Black sticky or thick menstrual blood
If your period blood looks black and feels sticky or thick, it’s usually just due to clotting. As your body sheds the uterine lining, blood can mix with that tissue and thicken in texture — especially when it’s older. It might look a little different, but it’s typically nothing to worry about.
When it’s best to see a healthcare professional
If you ever notice black menstrual blood along with other symptoms, like a fever, pelvic pain, a strong or unpleasant odor, or unusually large clots — it’s worth getting checked out. While darker blood on its own is often harmless, these extra signs can sometimes point to something more serious, such as an infection, fibroids, or another underlying condition. It’s best to see your OB/GYN if anything feels off or different from your usual cycle. Most of the time, though, black blood is simply older blood leaving the body — a normal part of how your period cleans house.
Black blood, red blood, and everything in-between
Black menstrual blood might look a little alarming at first glance, but for most people, it’s just another part of your body’s natural rhythm. Period blood can change in color, texture, and flow from month to month, and that variation often says more about timing than about health problems. Still, your cycle is a powerful messenger. Paying attention to what’s normal for you can help you catch any changes early and feel more confident about what’s happening in your body.
If something feels off, whether it’s black blood with a strong odor, severe cramps, or bleeding outside of your usual cycle, don’t hesitate to reach out to your OB/GYN. But if it’s just a few dark streaks at the start or end of your period? You can take a deep breath — your body’s simply doing its thing.
Nora Rosenfeld is an editorial intern at Rescripted, studying Journalism and Global Health at Northwestern University. She is passionate about women’s and mental health and plans to pursue health and science writing.
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