Lots of us associate menstrual blood with a bright red color.
So if you’ve noticed that your period is darker, it’s normal to wonder ’why is my period blood brown?’.
Here’s everything you need to know about why period blood can be different colors and when, if ever, it’s something to worry about.
In this article: 📝
- Is it normal for period blood to be brown?
- What does it mean if your period blood is brown?
- When else is brown period blood normal?
- When is brown period blood not normal?
Is it normal for period blood to be brown?
Yes. Most of the time, it’s normal for period blood to be brown, dark brown, or sometimes even black.
If you think about it, your period varies in a lot of ways —mainly consistency and heaviness.
It’s not the same every day Aunt Flo is in town.
So if you’ve noticed that your menstrual blood is brown on some days, it’s usually nothing to worry about.
We also know exactly what causes the color change.
What does it mean if your period blood is brown?
All that brown period blood means is that the blood was exposed to oxygen as it was leaving your body (and that’s not a bad thing).
Think of when a cut on your finger bleeds. It starts off bright or dark red. Later, as it starts to clot and scab, the blood looks browner.
That’s because, outside your body, the blood meets oxygen.
If you want to get really technical, the color change happens when the minerals in your blood, iron, and hemoglobin react with the oxygen from the air and darken.
Most people notice more brown blood on the first day of their period and towards the end.
Why is your period blood brown on the first day?
Because the blood and tissue that comes first take longer to separate from the wall of your uterus and longer to travel out of your vagina.
This means it’s exposed to oxygen for longer, so it turns brown.
Once the initial tissue has broken away, the small blood vessels in the uterus are open, so the blood flows faster.
The blood that leaves on your heaviest days has spent the least amount of time on its exit route (and the least amount of time in contact with the air), which is why it stays brighter red.
Towards the end of your cycle, things usually slow down again.
And what does dark period blood mean (or even black blood)?
It just means that the tissue took the longest to leave your body and was exposed to the most air on its way out.
When else is brown period blood normal?
There are also other times when it’s normal to see brown period blood.
- Women in menopause sometimes notice a brown vaginal discharge.
- After pregnancy, women usually bleed and spot for several weeks (known as lochia). Some of the blood or tissue released on lighter days may be darker because it’s taken longer to leave the body.
When is brown period blood not normal?
There can be times when brown period blood or brown vaginal discharge is not normal.
It’s worth noting, though, that if dark period blood does indicate another condition, it would be very unusual for that to be the only symptom.
You also need to watch out for these signs:
- Bleeding or spotting during pregnancy
- Bleeding regularly after sex
- Erratic periods or breakthrough bleeds
- Periods that last longer than usual
- Large blood clots
- A foul smell
- Abdominal, pelvic, or vaginal pain
If you notice brown bleeding in between periods, it can be a sign of polycystic ovarian syndrome (PCOS).
This condition can make your periods lighter, but it can mean that your body sheds old tissue at unpredictable times in your cycle as well.
If you have PCOS, though, you’ll probably have symptoms like irregular cycles, acne, weight gain, hair loss, and facial hair growth.
If brown blood also coincides with any of these symptoms, it might be a good idea to make an appointment with your doctor.
Generally, though, as long as your cycle is regular for you and you don’t have any other symptoms, brown period blood is nothing to be concerned about.