Brown discharge that lasts a full week is usually old blood leaving your body slowly, and in most cases it’s not a sign of something serious. The brown color comes from oxidation, the same process that turns a cut apple brown, happening when blood sits in the uterus or vaginal canal long enough to mix with air before it exits. That said, a week is on the longer end of normal, and several conditions beyond leftover period blood can explain why it’s dragging on.
Old Period Blood Is the Most Common Cause
The most straightforward explanation is that your uterus is simply slow to finish shedding its lining. After your period winds down, small amounts of blood can remain behind, gradually making their way out as brownish discharge over the following days. Many people experience this for a day or two after their period ends, but others have brown discharge that comes and goes for a week or two. How long it takes depends on how efficiently your uterus sheds its lining and the speed at which everything moves through the cervix and vaginal canal.
If the discharge started right after your period, is light enough that you don’t need more than a panty liner, and isn’t accompanied by pain or a strong smell, this is the most likely scenario. It’s essentially the tail end of menstruation, just slower than usual.
Hormonal Birth Control and Breakthrough Bleeding
Hormonal contraceptives are one of the most common reasons for prolonged spotting. If you recently started a new pill, switched methods, or missed a dose, your body may respond with days of light brown discharge as it adjusts to the changing hormone levels. This is called breakthrough bleeding, and it’s especially common in the first few months on a new contraceptive or with extended-cycle pills that reduce how often you get a period.
This type of spotting is generally harmless, but the Mayo Clinic notes that if breakthrough bleeding becomes heavy or lasts more than seven days in a row, it’s worth contacting your healthcare provider. A week of brown discharge right at that threshold suggests your body may need more time to adjust, or your current method may not be the right fit.
Ovulation Spotting
If your brown discharge showed up roughly two weeks before your next expected period, it could be tied to ovulation. When your body releases an egg, the brief hormonal shift can cause a small amount of bleeding from the uterine lining. That blood may take a day or two to travel out, arriving as light brown spotting. Ovulation spotting is typically very light (not enough to fill a pad or tampon) and lasts one to three days, so if yours has continued for a full week, ovulation alone probably isn’t the whole story.
Implantation Bleeding in Early Pregnancy
If there’s a chance you could be pregnant, brown discharge lasting several days could be implantation bleeding. This happens when a fertilized egg attaches to the uterine lining, usually one to two weeks after ovulation. Implantation bleeding is typically light pink or dark brown, lasts one to three days, and doesn’t include clots.
A full week of brown discharge would be unusually long for implantation alone, but some people experience light spotting that overlaps with other early pregnancy changes. If your period is late or you have other early pregnancy signs like breast tenderness or nausea, a home pregnancy test is the simplest next step.
Hormonal Imbalances and Irregular Cycles
Conditions that disrupt your normal hormonal rhythm can cause the kind of prolonged, irregular bleeding that shows up as brown discharge. Polycystic ovary syndrome (PCOS) is one of the more common culprits. With PCOS, ovulation doesn’t always happen on schedule. When you don’t ovulate, your body doesn’t produce progesterone the way it normally would, and the uterine lining keeps building up without the hormonal signal to shed properly. Eventually, parts of that thickened lining break down unevenly, leading to irregular spotting or prolonged light bleeding rather than a clean, predictable period.
Thyroid disorders, perimenopause, and significant stress or weight changes can create similar hormonal disruptions. If your periods have become unpredictable alongside the brown discharge, a hormonal imbalance is worth investigating.
Cervical Polyps and Fibroids
Small, noncancerous growths on the cervix or inside the uterus can cause spotting that lingers for days. Cervical polyps are smooth, tear-shaped growths, usually less than half an inch long, that develop from chronic inflammation or infections. They bleed easily, especially after sex or a pelvic exam, and that blood often appears as brown discharge by the time it reaches your underwear.
Uterine fibroids, which are growths in the muscular wall of the uterus, can similarly cause prolonged or irregular bleeding. Both polyps and fibroids are common and rarely dangerous, but they can explain why spotting sticks around longer than expected. If you notice bleeding after sex alongside the brown discharge, polyps are a strong possibility.
Infections That Cause Brown Discharge
Certain infections create irritation inside the vaginal canal or cervix, and that irritation can produce small amounts of bleeding. By the time the blood mixes with vaginal fluid and exits, it looks brown. Sexually transmitted infections like chlamydia, gonorrhea, and trichomoniasis can all cause this. So can bacterial vaginosis, though that’s not sexually transmitted.
The key difference between infection-related discharge and harmless old blood is that infections almost always come with additional symptoms. Watch for a strong or foul odor, pain in your lower abdomen, burning when you urinate, fever, or pain during sex. Pelvic inflammatory disease (PID), a more serious complication of untreated STIs, can cause all of these along with bleeding between periods. If your brown discharge smells unusual or comes with pelvic pain, getting tested sooner rather than later prevents the infection from progressing.
When a Week of Brown Discharge Needs Attention
A normal menstrual cycle involves bleeding that lasts two to seven days within a cycle that repeats every 24 to 38 days. Brown discharge that pushes your total bleeding time beyond seven days, or that appears completely outside your expected cycle window, falls into the category of abnormal uterine bleeding.
The discharge alone isn’t necessarily alarming, but certain patterns alongside it point to something that needs evaluation:
- Pain or cramping that feels different from your usual period discomfort
- Foul-smelling discharge, which suggests infection
- Bleeding after sex, which can indicate polyps or cervical changes
- Cycles that have become irregular, with missed periods or much heavier flow than usual
- Bleeding after menopause, which always warrants investigation regardless of the amount
- Soaking through a pad in an hour or two, which signals heavy bleeding that may need prompt care
If your brown discharge is light, painless, odor-free, and clearly connected to the tail end of your period or a recent change in birth control, a week of it is well within the range of normal variation. If it keeps recurring cycle after cycle, or if any of the red flags above apply, tracking the pattern and bringing it to your next appointment gives your provider something concrete to work with.