Spotting between periods is light bleeding that happens outside your normal menstrual cycle. It’s common, and in many cases it has a straightforward explanation like ovulation, birth control, or early pregnancy. But because it can also signal infections, growths in the uterus, or other conditions that benefit from early treatment, it’s worth understanding the full range of causes so you know what applies to you.
Spotting typically looks different from a period. The blood is often brown, dark brown, or pink rather than the bright or dark red of menstrual flow. It’s light enough that you might only notice it when wiping or as a small stain on underwear, and it usually lasts hours to a couple of days rather than the three to seven days of a typical period.
Ovulation Is the Most Common Harmless Cause
Many people notice a small amount of spotting around the middle of their cycle, roughly 14 days before their next period. This is ovulation spotting, and it happens because of a brief hormonal shift. In the days leading up to ovulation, estrogen levels climb steadily. Right after the egg is released, estrogen dips and progesterone starts to rise. That temporary imbalance can cause the uterine lining to shed just slightly, producing light bleeding that’s much lighter than a period.
Ovulation spotting is typically pink or light brown, lasts a day or two at most, and sometimes comes with mild cramping on one side of the lower abdomen. If the timing lines up with mid-cycle and the bleeding is minimal, this is usually nothing to worry about.
Birth Control and Breakthrough Bleeding
Hormonal contraceptives are one of the most frequent causes of spotting between periods, especially in the first few months of use. This is called breakthrough bleeding, and it happens more often with low-dose and ultra-low-dose birth control pills, the implant, and hormonal IUDs.
The timeline for when it resolves depends on the method. With hormonal IUDs, spotting and irregular bleeding in the first months after placement usually improve within two to six months. The implant works differently: whatever bleeding pattern you experience in the first three months tends to be your pattern going forward. So if you’re still spotting frequently after three months on the implant, that’s likely to continue. Missing pills, taking them at inconsistent times, or switching formulations can also trigger breakthrough bleeding.
Implantation Bleeding in Early Pregnancy
If there’s any chance you could be pregnant, spotting may be an early sign. Implantation bleeding occurs when a fertilized egg attaches to the uterine lining, usually about seven to ten days after ovulation. The blood is typically brown, dark brown, or pink and lasts anywhere from a few hours to a couple of days.
The key differences from a period: implantation bleeding is lighter, shorter, and doesn’t intensify over time the way menstrual flow does. It also arrives earlier than your expected period. A home pregnancy test is reliable starting around the first day of a missed period, so if you notice light spotting a week or so before your period is due, it’s worth testing once you’re far enough along for an accurate result.
Uterine Polyps and Fibroids
Benign growths inside the uterus can cause spotting that recurs cycle after cycle. Uterine polyps are small, soft growths that form when cells in the uterine lining overgrow. They attach to the uterine wall by either a broad base or a thin stalk and are sensitive to estrogen, meaning they can grow in response to the body’s normal hormone production. Polyps commonly cause bleeding between periods, irregular cycles, and sometimes heavier-than-usual menstrual flow.
Fibroids, which are growths in the muscular wall of the uterus, can produce similar symptoms depending on their size and location. Fibroids that push into the uterine cavity are the ones most likely to cause irregular bleeding. Both polyps and fibroids are typically identified through ultrasound and are treatable, so persistent spotting that doesn’t have an obvious explanation is worth investigating.
Infections and Pelvic Inflammatory Disease
Sexually transmitted infections like chlamydia and gonorrhea can inflame the cervix, making it more fragile and prone to bleeding, particularly after sex or between periods. Left untreated, these infections can progress to pelvic inflammatory disease (PID), an infection of the reproductive organs. PID symptoms can include bleeding between periods, pain or bleeding during sex, unusual discharge, and lower abdominal pain.
The tricky part is that many STIs and even PID can be present with very mild symptoms or none at all. If spotting is accompanied by any pelvic discomfort, unusual discharge, or pain during sex, screening for infections is an important step.
When Spotting Needs Medical Attention
A single episode of light mid-cycle spotting, especially if you can connect it to ovulation, a new contraceptive, or a missed pill, is rarely urgent. But certain patterns and symptoms shift spotting from “probably fine” into territory that warrants a visit to your doctor. The American College of Obstetricians and Gynecologists flags the following as reasons to get evaluated:
- Spotting that recurs across multiple cycles without a clear cause
- Bleeding after sex
- Cycles shorter than 21 days or longer than 35 days
- Cycle lengths that vary by more than 7 to 9 days from month to month
- Any bleeding after menopause
- No period for 3 to 6 months (when not pregnant or on hormonal contraception)
If you’re soaking through a pad or tampon every hour for more than two hours in a row and also feel dizzy, lightheaded, or short of breath, that’s an emergency.
What Happens at a Doctor’s Visit
If you go in for persistent spotting, the first steps are typically a pregnancy test and a blood test to check for anemia, since ongoing irregular bleeding can gradually lower your iron levels. From there, the most common imaging tool is a transvaginal ultrasound, which gives a detailed view of the uterine lining and can reveal polyps, fibroids, or other structural causes.
For people 45 and older, or younger people with risk factors like a long history of irregular cycles, a biopsy of the uterine lining may be recommended to rule out abnormal cell changes. This is a quick in-office procedure. The overall goal of the workup is to sort the spotting into a category: hormonal, structural, infection-related, or pregnancy-related. Once the cause is clear, treatment is usually straightforward.