Brown discharge is almost always old blood. When blood leaves the body quickly, it looks red. When it stays in the uterus or vaginal canal longer, it has time to oxidize, turning brown before it exits. In most cases, this is completely normal and tied to your menstrual cycle. But brown discharge can also signal hormonal changes, infections, pregnancy, or other conditions worth paying attention to.
Old Blood at the Start or End of Your Period
The most common cause of brown discharge is simply the tail end of your period. Your menstrual flow is generally slower at the beginning and end of your cycle. That slower flow gives the blood more time to oxidize, which is why the last day or two of your period often looks brown rather than red. Sometimes there’s a small amount of blood left over from menstruation that the body breaks down and expels gradually over the following days. This is normal and doesn’t need treatment.
Ovulation and Mid-Cycle Spotting
A small number of people, roughly 3%, experience spotting around the midpoint of their cycle when an egg is released from the ovaries. Even a single drop of blood from your cervix or uterus can mix with vaginal fluid to create brownish discharge. The cervix is fragile and sometimes bleeds a little on its own. This kind of mid-cycle spotting is especially common in younger women who’ve recently started menstruating, but it can happen to anyone.
Hormonal Birth Control
Any type of hormonal contraception can cause brown spotting, including pills, IUDs, the implant, the shot, the ring, and the patch. This is called breakthrough bleeding, and it happens because the hormones in your contraceptive affect how your uterine lining builds up and sheds. It’s more common with low-dose and ultra-low-dose pills, implants, and hormonal IUDs.
With IUDs, spotting and irregular bleeding in the first months after placement is very common. This usually improves within two to six months. With the implant, the bleeding pattern you have in the first three months tends to be the pattern going forward, so if you’re still spotting after that window, it’s worth discussing alternatives with your provider.
Implantation Bleeding in Early Pregnancy
About 1 in 4 pregnant women experience implantation bleeding, which happens when a fertilized egg embeds itself into the uterine lining. This typically occurs 10 to 14 days after ovulation and produces very light spotting that’s usually pink or brown. It looks more like vaginal discharge than a period, lasts a few hours to about two days, and shouldn’t soak through pads or produce clots. Any cramping is mild, lighter than period cramps.
If you’re sexually active and see light brown spotting around the time you’d expect your period, a pregnancy test is a reasonable next step. Bright red blood, heavy flow, or clots are not typical of implantation bleeding and point to something else.
Hormonal Imbalances
Estrogen helps stabilize the uterine lining. When too little estrogen circulates, that lining can break down at random points throughout your cycle, producing brown spotting between periods. Several conditions can cause this kind of hormonal imbalance.
Polycystic ovary syndrome (PCOS) is one of the more common ones. It often leads to irregular or infrequent periods, sometimes with more than 35 days between cycles. The extended time between periods means blood sits longer before being shed, which results in brown discharge when it finally exits. Ovarian cysts, which are fluid-filled sacs on or in the ovaries, can also cause brown spotting along with pelvic heaviness or pain.
Perimenopause and Menopause
Perimenopause, the transition period before menopause, typically begins in a woman’s mid-to-late 40s and lasts an average of four years, though it can stretch from a few months to a full decade. During this time, estrogen and progesterone levels fluctuate unpredictably from month to month. These erratic shifts affect ovulation and the rest of the menstrual cycle, making irregular bleeding and brown discharge common.
After menopause, dropping estrogen levels cause the vaginal walls to become thinner and more fragile, a condition called vaginal atrophy. The blood vessels in the vaginal tissue shrink, and small amounts of bleeding can occur. This blood often appears brown by the time it exits. Any vaginal bleeding after menopause, even brown spotting, is worth getting evaluated since it can occasionally indicate changes in the uterine lining that need attention.
Infections
Bacterial vaginosis (BV) is caused by an overgrowth of bacteria in the vagina and can change the color of your discharge. Brown discharge from BV is usually more noticeable around your period and after sex. The hallmark symptom is a fishy odor, which gets stronger when the bacteria interact with blood or semen.
Trichomoniasis, a sexually transmitted infection caused by a parasite, can also produce brown discharge. The parasite causes irritation inside the vagina, and that irritation sometimes leads to small flecks of blood that turn brownish by the time they exit. Other STIs like gonorrhea and chlamydia may not cause obvious symptoms early on, but over time they can produce spotting between periods and discharge that’s a different color or smell than what’s normal for you.
Endometriosis
Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus, on the ovaries, fallopian tubes, or elsewhere in the pelvis. This tissue still responds to hormonal cycles and sheds, but it has no way to leave the body. The result can be severe pain and brown discharge. If you have persistent brown spotting along with painful periods, pain during sex, or chronic pelvic pain, endometriosis is one possibility to explore with your provider.
After Childbirth
Vaginal discharge after giving birth, called lochia, follows a predictable color pattern. The initial discharge is dark red, but after about a week it transitions to a pinkish-brown color. This pinkish-brown stage typically lasts from roughly the fourth through twelfth day postpartum, then gradually shifts to yellow and finally white over several weeks. This timeline applies whether you delivered vaginally or by C-section.
Ectopic Pregnancy and Miscarriage
Brown spotting can sometimes signal a pregnancy complication. In an ectopic pregnancy, a fertilized egg implants outside the uterus, most commonly in a fallopian tube. Brown spotting is one early sign, often accompanied by pain on one side of the abdomen, low back pain, shoulder pain, dizziness, or fainting. This is a medical emergency.
Miscarriage can also begin with brown discharge, sometimes as a sudden gush of brown fluid that progresses to heavy red bleeding. If you know or suspect you’re pregnant and experience brown discharge along with cramping or heavier bleeding, seek medical care promptly.
Cervical and Uterine Conditions
Persistent brown discharge that doesn’t stop can, in rare cases, be a symptom of cervical cancer. The discharge may be watery, pale, pink, brown, or bloody, and it may have an unusual smell. Precancerous cervical changes can’t be seen with the naked eye, which is why routine Pap tests matter. If a Pap test detects abnormal cells, the next step is typically a closer examination of the cervix under magnification, sometimes with a small tissue sample taken for testing.
Signs That Need Attention
Brown discharge on its own, especially around your period, is rarely cause for concern. But certain accompanying symptoms change the picture. A fishy or foul odor points toward infection. Brown spotting that continues for weeks without explanation, or that appears after menopause, warrants investigation. Pain in the pelvis or abdomen alongside brown discharge may suggest endometriosis, ovarian cysts, or ectopic pregnancy. And if you’re pregnant and notice brown discharge getting heavier or turning red, that needs prompt evaluation.