10 Causes of Spotting After a Missed Period

Breana Johnson

11/6/2024

Your period was late, and now there’s a little blood in your underwear.

Is it a light period? An early sign of pregnancy? It could be either. Or, if something else has thrown your hormones out of balance, your spotting could have a completely different cause.

The sooner you know what’s behind your bleeding, the sooner you can be proactive about your health. So we’ve rounded up 10 different possible causes of spotting after a missed period. And when it’s time to take a pregnancy test.

What is spotting?

Spotting is a general term for any non-menstrual vaginal bleeding, or any bleeding not considered your period. It can happen at any point during your cycle, even after a missed period. And spotting is light, not usually enough to fill a pad or tampon. It could be a few drops of blood on a piece of toilet paper after wiping.3,7

It’s not always an immediate cause for concern. But if you’re spotting after never experiencing it before, or it’s accompanied by pain or other unusual symptoms, investigate a possible cause.

“Spotting” that’s actually a light period

Your “spotting” could actually be a light period, especially if it occurs within a day or two of when you were expecting “Aunt Flo.” You can probably consider it a light period if other usual period or PMS symptoms are also present. Light bleeding at the beginning or end of your normal period is not typically considered spotting (think within two days of either end).

But if your period is shorter or lighter than normal, it’s probably caused by a hormonal imbalance or change. Many things can throw off the monthly flux of hormones that drive your menstrual cycle. Things like chronic stress, a significant change in diet or exercise, or even an underlying medical issue.

If your periods are growing lighter or more irregular, there’s most likely an underlying issue that needs to be addressed.

Spotting as a sign of pregnancy

Spotting instead of a period CAN indicate pregnancy. This light bleeding, usually called implantation bleeding, is a normal symptom of early pregnancy, although not every woman experiences it.

Implantation bleeding can occur around one to two weeks after fertilization, when a fertilized egg attaches itself to the uterine lining and light bleeding follows. Because this is around the time you would expect your period, it’s easy to mistake it for a light period.5

What does implantation bleeding look like?

Implantation bleeding is lighter than your usual period, and is usually a different color. Think anything from a rust-colored brown to light pink, as opposed to the brighter or darker red of period blood. It may also last only one or a couple of days. A typical period could last anywhere from three days to a week or more.2,13

If you’re experiencing other common early pregnancy symptoms, such as nausea, breast tenderness, and fatigue, consider taking a pregnancy test.

Spotting because of hormonal birth control

If you’re on hormonal birth control, the hormones in your contraceptive can cause irregular bleeding and spotting.

This is especially true if you have recently started, stopped, or switched birth control. Your body will be responding to the sudden introduction or withdrawal of hormones. If you’re in any of these situations, expect unpredictable bleeding or spotting for a couple months.

Some hormonal birth control methods are a combined oral contraceptive (COC) and create monthly “withdrawal bleeds.” These mimic your period (like birth control pills, the patch, or vaginal ring). The combined synthetic estrogen and progestin in these methods can initially cause some months of spotting that may stop over time. “Breakthrough bleeding” between your withdrawal bleeds can also occur, especially if you’re taking a COC with a lower dose of estrogen.11

Progestin-only birth controls (think the “mini-pill,” hormonal IUD, implant, or contraceptive shot) tend to cause unpredictable bleeding and spotting. This is because they lack the synthetic estrogen used to create predictable, monthly withdrawal bleeding. Unpredictable spotting on a progestin-only birth control may decrease over time, and for some women monthly bleeding ceases entirely.6,9

Spotting from lack of ovulation

The hormonal changes leading up to and after ovulation are what trigger your monthly period—if the egg released into your fallopian tube from your ovaries is not fertilized.

Lack of ovulation, or anovulation, will therefore affect your period, like a hormonal domino effect. In fact, you can’t have a true period without first ovulating. This is a similar concept to early pregnancy: when your body stops ovulating, your periods also stop.6

Not ovulating can cause a lighter type of bleeding around your expected period.

Anovulation not related to pregnancy, or inconsistent ovulation, is not normal. It usually indicates a hormonal imbalance, either temporary or long-term. That imbalance could be caused by many of the other reasons covered in this article.

Being underweight, diet and exercise changes, chronic stress, or a medical issue like PCOS can disrupt ovulation and cause spotting instead of your period.8

What if my birth control is stopping ovulation?

One of the main functions of hormonal birth control is suppressing ovulation. This is why you can experience spotting instead of your period, or a cessation of your periods altogether.

Combined oral contraceptives that contain synthetic estrogen help create a predictable, monthly “withdrawal bleed” that looks like your period. But if you’re not ovulating on birth control, you aren’t getting an actual period either.

Spotting as a sign of STIs

Sexually transmitted infections (STIs), like chlamydia or gonorrhea, can cause spotting at any point of your cycle. These STIs may also be accompanied by nausea, painful urination, a fever, or green or yellow discharge. So if you’re spotting with these additional symptoms, consider getting tested.6

Pelvic Inflammatory Disease

If STIs are left untreated, they can progress, among other things, into pelvic inflammatory disease (PID). PID may display the symptoms listed above in addition to pelvic pain, worse fever or chills, and bleeding after sex. Both STIs and PID can cause spotting around the time of your expected period (or at any point of your cycle). Both require treatment.6

Spotting from low body weight or excessive exercise

Low body weight that leads to irregular or missed periods, or light spotting instead of a normal period, usually indicates malnutrition.

Loss of “non-essential” functions

If you’re not taking in enough calories or nutrients, your body may go into a kind of “starvation mode.” When this happens, your body redirects energy away from “non-essential” functions like ovulation to “essential” biological functions that keep you alive.

If malnutrition is causing you to ovulate inconsistently or not at all, this can lead to spotting or, eventually, a total lack of periods. This condition is called amenorrhea and is caused by hormonal disruptions from malnutrition, low energy reserves, and lack of ovulation.6

Other symptoms of eating disorders such as anorexia (or simply being underweight) include hair loss, acne, and dizziness. If you’re spotting during your period or missing your period due to lack of nutrition, it’s important to seek help.

Excessive exercise

It’s worth noting that amenorrhea is not only caused by eating disorders. Many athletes find that their high level of physical activity, combined with a low body weight and inadequate nutrition, can cause irregular periods. They can also experience light spotting instead of a normal period, or even stop their periods altogether.

This condition even has a name: “athletic amenorrhea.” It’s one part of the Female Athlete Triad, a trio of medical conditions that can affect female athletes.1

Whatever the cause of amenorrhea, talk to your doctor to avoid the additional risks of bone loss and infertility over time.

Spotting because of thyroid issues

Both hypothyroidism (the production of too little thyroid hormone) and hyperthyroidism (the production of too much thyroid hormone) can cause bleeding changes in your menstrual cycle. Other symptoms include fatigue, weight fluctuation, and changes in heart rate.

Hyperthyroidism especially can cause irregular or lighter periods, along with weight loss, hyperactivity, anxiety, and trouble sleeping.12 If you suspect you may be having thyroid issues, make an appointment with your doctor. They can check for typical symptoms and test your hormone levels with a blood test.

Spotting because of Polycystic Ovarian Syndrome (PCOS)

Polycystic ovarian syndrome (PCOS) is caused by an overproduction of androgens by your ovaries. This hormonal imbalance then interrupts or inhibits the process of ovulation.

Your ovaries develop follicles leading up to ovulation. But if the follicle (and the egg inside) is never released, you may still experience spotting instead of your actual period.

Some other telltale symptoms of PCOS include:

the presence of multiple cysts on your ovaries

• the presence of multiple cysts on your ovaries

weight gain

• weight gain

balding

• balding

excess hair

• excess hair

acne6

• acne6

Spotting because of cervical or uterine cancers

The above are the most common reasons for spotting after a missed period. But there are other, less common reasons you could be missing a period and experiencing light bleeding instead.

In rare cases, women may spot as a symptom of cervical or uterine cancers. Although this is rare, it’s wise to speak to your doctor if you have a family history of these cancers.6

When to take a pregnancy test

If you’re spotting around the time of your expected period and experiencing other symptoms of early pregnancy, take a pregnancy test. Consider waiting until your period is a few days late to ensure an accurate result.

If your pregnancy test is negative, and you’re wondering whether you can trust the result, check out our article on the most common causes of false negative pregnancy tests.

Conclusion

There are many reasons why women experience spotting instead of a period. It could be linked to pregnancy, your birth control, an underlying health condition, or a hormonal imbalance affecting ovulation. It could also be a very light period.

With support and medical advice from a healthcare professional, always investigate any concerns you have about spotting or changes to your menstrual cycle. Especially if it’s “out of the norm” for your body.

Sources

1. American College of Obstetricians and Gynecologist. 2017. “Female Athlete Triad.” The American College of Obstetricians and Gynecologists. https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/06/female-athlete-triad.
2. American Pregnancy Association. 2020. “What is Implantation Bleeding?” American Pregnancy Association. https://americanpregnancy.org/pregnancy-symptoms/what-is-implantation-bleeding-24176/.
3. Clue. 2018. “Spotting and bleeding between periods.” Clue. https://helloclue.com/articles/cycle-a-z/what-is-spotting 
4. Dasharathy, Sonya S. 2012. “Menstrual Bleeding Patterns Among Regularly Menstruating Women.” American Journal of Epidemiology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3299419/.
5. Marcin, Ashley. 2018. “How Long Does Implantation Bleeding Last? What to Expect.” Healthline. https://www.healthline.com/health/pregnancy/how-long-does-implantation-bleeding-last#:~:text=Implantation%20bleeding%20is%20generally%20light,start%20of%20a%20menstrual%20period.
6. Marcin, Ashley. 2019. “What Does It Mean If You Have Spotting Instead of Your Period?” Healthline. https://www.healthline.com/health/womens-health/spotting-instead-of-period#pregnancy.
7. Marks, Julie. 2019. “What Causes Spotting Before Periods?” Healthline. https://www.healthline.com/health/womens-health/spotting-before-periods.
8. Meisel, Lindsay. 2019. “Breakthrough Bleeding: Why You Can Get Your Period Without Ovulating.” Ava. https://www.avawomen.com/avaworld/breakthrough-bleeding/.
9. Ray, Laurie. 2019. “Progestins 101.” Clue. https://helloclue.com/articles/sex/progestins-101.
10. Stoppler, Melissa. 2019. “article Spotting vs. Period: How to Tell the Difference.” MedicineNet. https://www.medicinenet.com/spotting_vs_period_differences/article.htm.
11. Sullivan, Debra. 2019. “SUBSCRIBE Search Healthline What You Need to Know About Breakthrough Bleeding on the Pill.” Healthline. https://www.healthline.com/health/womens-health/breakthrough-bleeding-on-the-pill#causes.
12. Telfer, Nicole. 2018. “Hyperthyroidism and the menstrual cycle.” Clue. hyperthyroidism-and-the-menstrual-cycle.
13. Van de Roemer, Niels. n.d. “Spotting vs. Period.” Daysy. Accessed December 2, 2020. https://usa.daysy.me/learn-more/spotting-vsperiod/.