It may not be a common discussion, but your period can sometimes effectively determine the state of your health. Its color can indicate whether or not there’s something wrong. But if you’ve woken up one day thinking, “why is my period blood brown?” should you be concerned?

In this guide, we will dive into the causes for period blood, looking different from what you expect, what it means, and when you should get a physician’s opinion.

So, Why Is My Period Blood Brown?

Since you began menstruating, you may have become used to the color of your period looking a certain way. Along with this, consistency, texture, and flow are also critical indicators to which you’ve likely become accustomed. Seeing a different color or consistency altogether may be alarming, particularly if you’ve been having other health issues, related or otherwise.
But luckily, there’s no need to fear, as there is a simple explanation.

Period blood can have a range of different colors and consistencies while being completely normal. It’s normal to see orange, dark red, bright red, brown, or even black blood, and each color signals something different about the way your uterine lining is shedding itself.

The tissues inside your uterus prepare for the successful implantation of a fertilized egg every cycle. When this doesn’t happen, the lining tissues start to break down and descend the uterus to be ejected out of the body. However, the tissues and blood begin to get exposed to air at this point, causing the blood to oxidize. Specifically, there is an oxygen-carrying protein in each red blood cell, called hemoglobin. This protein has iron molecules that bind to oxygen, giving it a bright, rich color.

However, when blood is exposed to air, the oxidation gives it a brownish hue. You can think of brown blood as simply being “older” blood. A good example is that it’s just like when the topmost layer on an old iron gate will oxidize and turn to rust, which can be a similar shade of brown.

Other Reasons for Brown Period Blood

If the period blood is even older than this, it can sometimes turn black. Both brown and black blood colors are generally no cause for alarm. Your period may be black or brown at the very beginning or end when the flow is lighter. Heavier, faster flow is likely to be a darker or brighter red color.

Your period blood may also turn brown if you have a lot of iron in your diet, which enhances the speed at which period blood oxidizes once it contacts air. Also, if you have birth control with a low-to-zero dose of estrogen, it can destabilize your uterine lining and lead to breakthrough bleeding in the middle of your cycle. But again, this blood is merely brown because of oxidation.


We hope we’ve put your fears at ease with this post. Brown period blood, when occurring naturally as part of your cycle, is usually normal.

If, however, you’re experiencing brown period blood outside your normal cycle or after sexual activity, it could be related to a more complicated cause, and you should contact your healthcare provider.

At the Internal Medicine Diagnostic Center, we specialize in providing high-quality preventive care to all of our patients. We are your primary care professionals in the heart of Texas, ensuring that our patients live happy, healthy lives. If you have any questions about your health, don’t hesitate to contact us at our Magnolia location at (281) 252-8600 or our Houston location at (281) 252-8600.

We look forward to hearing from you.

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