Why is my Period Blood Brown?

So, when do you usually notice brown period blood? 

Period blood tends to appear brown near the start and end of your period. At the start of your period, flow is typically light, which can result in period blood that isn’t very red. It can also be the result of tiny amounts of blood leftover from your previous period. 

Near the end of your period, period blood is brown as a result of oxidation. The longer the blood remains in the uterus, the more it oxidizes (gets exposed to air), resulting in a brownish color. Iron supplements may also enhance the process of oxidation leading to brown period blood. All of these situations are completely normal. 

You might also experience brown vaginal discharge between periods. This is called spotting or breakthrough bleeding. This is a common occurrence among people taking birth control, specifically ones that are progestin only or contain low amounts of estrogen. The lack of estrogen in the pill may cause instability in the uterine lining, causing it to shed a little bit in between periods. The discharge may be pink or brown in color. A similar reaction can occur to other forms of progestin only birth controls such as IUDs and implants. Once the body adjusts to the hormones, the breakthrough bleeding will most likely disappear. 


Another common cause of brown period blood or brown discharge is mild trauma to the vagina. For example, having sex or even a PAP smear can cause irritation in the uterine lining causing small amount of blood loss. The blood, mixed with normal discharge, may appear brown in color. 

Now that we’ve covered the times when brown period blood is normal, let’s talk about when it’s NOT normal. 

  • Let’s say your period blood is consistently brown, and not just on the first or last day. 🤔

  • We’ve already talked about the causes of brown period blood on the first day of your period and near the end. While this is normal, it is NOT normal for your blood to be brown throughout your whole period, consistently. This could be a sign of a greater issue such as low progesterone levels. Progesterone is released by the ovaries during ovulation, and its function is to thicken the uterine lining and prepare it for a potential pregnancy. Low progesterone levels may result in your uterine lining being not as thick leading to less blood flow. If you suspect that this could be the case, definitely speak to your doctor! In the meantime, check out our en-cycle-pedia that shows you how estrogen and progesterone levels fluctuate through the cycle.

    Not only can low progesterone cause brown period blood, it can also cause premature shedding of the uterine lining leading to spotting between periods. Why does this happen? Progesterone not only thickens the uterine lining but it also holds it altogether until your period begins. Therefore, low progesterone can cause instability in the lining causing some parts to shed before your period is due. 

    Like we mentioned, spotting can also be a result of your body adjusting to birth control, so if you feel that this is the case, then don’t worry. If not, there’s no harm in checking with your doc! Untreated low progesterone may increase the risk of infertility in the long run, so it’s definitely better to be safe than sorry. 

  • It could also be a vaginal infection. 😯

  • Discharge tends to be a taboo subject, but once again, everyone gets it. Normal discharge is described to be clear or “milky”. When discharge becomes tainted with a brownish color, it may be worthwhile to visit your doctor. This could be a sign of a sexually transmitted infection such as Chlamydia and Gonorrhea. In the case of an infection, other symptoms that you should look out for include: foul smelling discharge, increased amount of discharge, painful urination, itchiness, and even a fever. If you experience any of these symptoms, immediately speak to your doctor, as untreated infections may develop into pelvic inflammatory disease (PID). PID symptoms include pain in the pelvic and lower abdomen area and pain during sex. 

  • Another culprit could be PCOS (polycystic ovarian syndrome). 😖

  • PCOS is characterized by an underlying hormonal imbalance, usually paired with cysts on the ovaries and irregular cycles. One of the physical signs of the disorder can be brown discharge, as a result of imbalances in reproductive hormones such as estrogen, progesterone, and androgen. In many cases, the brown discharge may replace a regular period. If you experience brown discharge alongside symptoms such as irregular menstrual cycles, acne, dark patches on the skin, etc., then you should consult with your doctor, as this may be a sign of PCOS. While the cause of PCOS is unknown, it affects about 10% of women of reproductive age and can be managed with proper diet, exercise, and medical interventions. 

  • Along the lines of PCOS, brown discharge could be a sign of endometriosis. 😱

  • Endometriosis is a condition in which endometrial tissue grows outside of its normal spot, which is the lining of the uterus. Endometrial tissue may begin to grow on your ovaries or along the pelvis, which can cause inflammation and intense pain. Similar to how your uterine lining sheds and becomes your period, the endometrial tissue growing outside of that area will also shed. However, unlike your period, the broken down tissue cannot exit the uterus and will cause internal bleeding. The internal bleeding may escape and appear as brown discharge. Some symptoms that indicate endometriosis include pain during sex, painful urination and bowel movement during periods, and agonizing lower abdomen and back pain. Here’s an article we wrote on managing endometriosis!


    Hopefully, we didn’t scare you by telling you about all the abnormal causes of brown period blood and brown discharge. 🥴 Even if we did, we hope you know that you’re not alone, and seeking medical help is the way to go! 


    The Aavia app helps you keep track of it all, for free. 😌 Daily logging helps you stay in control of your period symptoms including discharge. If you just started birth control, you can track the days where you might have experienced breakthrough bleeding. Tracking your cycle is super important, especially if you may want to get it checked out for any of the disorders we mentioned above.