By OB/GYN Dr. Kimberly Langdon
Menstrual blood can change in color depending on what day of flow you are on. It typically starts out pink, then turns red and tapers off to brown. So brown is usually the color that you will see towards the end of your cycle but is not the case with everyone.
To reassure you if you are one of those people who sees brown blood first, I am here to let you know that brown, pink, red, orange and even black (!) are all considered normal variants of menstrual blood color.
Why is my Menstrual Blood Brown Sometimes?
The reason that menstrual blood turns brown is that it starts to break down before it exits the uterus. The last few drops of blood linger on the surface of the lining of the uterus. Hemoglobin is what gives blood its red color so darker colored bleeding is just a sign that the blood has oxidized, meaning it is “old blood”.
Hemoglobin binds to iron, which binds to oxygen. As oxygen leaves the red blood cells, it turns the cells brown—kind of like how iron gets rusty.
Menstrual blood is also mixed with cells and mucus that can contribute to discoloration.
One other cause of brown blood is from ovulatory bleeding that can occur at mid cycle. Often, there is some cramping or lower abdominal pressure associated with ovulation.
Is it Normal?
Yes, brown blood is totally normal unless it is brown for your whole period.
When Should I Talk to My Doctor?
It’s time to call your doctor if:
Brown blood is associated with:
- Pelvic pain
- Foul-smelling discharge
- It turns from brown to grey
- Symptoms like fatigue or constipation (this could be linked to a thyroid problem)
- Your period lasts longer than seven days or is very heavy such as saturating a pad or tampon every hour or two.
- Clots larger than a quarter that do not stop after an hour or two.
- If you have a fever, foul-smelling blood (or discharge) or a grayish hue (this could be a sign of a sexually transmitted disease such as gonorrhea or chlamydia).
- You are bleeding in between periods, have cycles shorter than 23 days or longer than 36 days.
- Any blood-tinged bleeding or brown discharge after menopause.
Brown Discharge and Pregnancy
Brown discharge during pregnancy can be due to implantation bleeding, cervical changes, and possibly miscarriage. At the time of implantation, the embryo must burrow into the wall of the uterus to establish a blood supply, and this can cause the release of blood. The hormones of pregnancy make the cervix softer, and it is rich in capillaries or small blood vessels that can spontaneously burst or leak with trauma or intercourse. Miscarriages can have no symptoms, or you may notice brown or pinkish discharge long before the pregnancy passes on its own. Premature contractions or preterm labor can cause spotting that is pink, red, or brown.
The final word is that blood from anywhere in the body can change color over time. There is generally no need for concern over brown menstrual blood, especially if it only lasts a day or so.
Kimberly Langdon M.D.
Kimberly Langdon is a Doctor of Medicine and graduated from The Ohio State University in 1991. She completed her residency in Obstetrics and Gynecology at The Ohio State University Hospitals, Department of OB/GYN. Board-Certified in 1997, she is now retired from clinical practice after a long and successful career. Currently, she is the Founder and Chief Medical Officer of a Medical Device Company that is introducing a patented product to treat vaginal microbial infections without the need for drugs. She is an expert in Vaginal Infections, Menstrual disorders, Menopause, and Contraception.