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:
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.
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.
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.