If you've ever wondered, "Wait, why is my period lasting so long?" after buying yet another box of tampons, you're not alone. While some women have their period schedule and routine down pat from the first onset of PMS symptoms, it's also common to deal with irregular cycles, including short periods or ones that never seem to end. But when is this a cause for concern?
Your period can last anywhere between two and seven days, with longer cycles being more common during the first few years after menstruation begins, per Mayo Clinic. Although your menstrual cycle tends to shorten and become more regular over time, this isn't always the case. Between period cramps, mood changes, bloating, and fatigue, it's normal to want to kiss Aunt Flo goodbye after a while.
Whether you got your period twice in one month or feel like it lasts forever, it's natural to have some concerns. Here's everything you need to know about your menstrual cycle length, what causes long periods, and how to know when it's time to see your doctor.
Meet the experts: Jessica Shepherd, MD, is an ob-gyn and menopause expert based in Dallas, Texas. Tom Toth, MD, is a reproductive endocrinologist at Boston IVF and an associate professor of obstetrics, gynecology, and reproductive biology at Harvard Medical School. Jodie Horton, MD, is an ob-gyn, clinical assistant professor at Georgetown University, and chief wellness advisor at Love Wellness. Sherry Ross, MD, is an ob-gyn and author of She-ology. Christiane Northrup, MD, is an ob-gyn and the author of Women’s Bodies, Women’s Wisdom.
How long does your period last?
There's a pretty big range of "normal" when it comes to period length, says Jessica Shepherd, MD, an ob-gyn and menopause expert based in Dallas, Texas. "Usually, it can last anywhere between five to seven days, but there are times at which it can be a few days longer or shorter," she says.
The length of your period differs based on hormonal shifts during your cycle, which can impact endometrium development, and in turn, the number of days it takes for it to shed, Dr. Shepherd explains. If your period is a day or two longer or shorter than your usual period length, it's probably normal—but in some cases, it may be something more serious.
What causes long periods?
1. You have an IUD.
One of the most common causes of long periods are intrauterine devices (IUDs), a type of birth control placed directly into your cervix. There are two main types: a non-hormonal, copper-based IUD (like Paraguard), and a hormonal, progestin-based IUD (like Mirena and Skyla).
It turns out that both can cause abnormally long bleeding, especially right after insertion, says Tom Toth, MD, a reproductive endocrinologist at Boston IVF. Longer, heavier periods are a known side effect of the copper IUD. The progestin IUD, however, is often marketed to women as a way to reduce or even eliminate their periods. And while it typically does have that effect over time, the first few cycles may have more or longer bleeding than usual, he says.
With either IUD, if the prolonged periods don't settle down after three cycles, it's time to go back to your doctor, as it's possible the IUD moved out of position or simply doesn't play nice with your body.
2. You're ovulating.
Menstruation is your body's way of getting rid of the extra blood and tissue it saved up in case your egg got fertilized, but sometimes the hormonal signals get crossed and you can bleed when you release the egg too, says Sherry Ross, MD, an ob-gyn and author of She-ology.
This occurrence is known as "intermenstrual bleeding," and it happens as a result of the slight dip in estrogen that happens around ovulation, which can cause spotting. If the bleeding lasts a few days or happens close to the end of your last cycle, it may seem like your period is continuing forever. It's not normally something to worry about, but if it changes suddenly or if you have serious pain, see your doctor.
3. You're pregnant (yes, really).
Isn't the tell-tale sign of pregnancy no periods? Yes, but not all the time, Dr. Toth says. "A common cause for abnormal menses, including longer bleeding, is pregnancy," he says, even if "typical" symptoms of pregnancy, like nausea, are absent. "Any time a woman has unusual bleeding, it's always best to eliminate possibility of pregnancy with a blood test for pregnancy for reassurance," Dr. Toth says.
4. You're on hormonal birth control.
Anything that manipulates your hormones has the potential to make your periods longer, says Dr. Toth. This includes all types of hormonal birth control like the pill, patches, rings, shots, and implants. There are many options with varying levels and types of hormones, so if your body doesn't respond well to one type or dosage, there's a good chance you can find a different one that will work. The length of your period is just one factor your doctor will use to help you determine which type of birth control works best for you.
5. You had an early miscarriage.
Early miscarriages are much more common than you may realize. Up to half of all pregnancies end in miscarriage, often before the woman even realizes she was pregnant, and about one in 100 women suffer from repeat miscarriages, according to the March of Dimes.
Sometimes the only sign of this is an extra-heavy or long period. Your menstrual cycle length should return to normal within one to two cycles, but if it stays abnormally long after three cycles, call your doctor, Dr. Toth says.
6. You have PCOS.
Polycystic ovary syndrome (PCOS) affects about 10 percent of women of childbearing age, per the Office of Women's Health (OWH). PCOS also wreaks havoc on hormone levels, sometimes causing weight gain, excess hair growth, and (you guessed it) prolonged periods, Dr. Toth says. You'd think that not ovulating would give you a free pass on bleeding, but the opposite is often true, he adds—no egg means long, wacky cycles.
If you're experiencing super-long periods along with other signs of PCOS, like migraines, facial hair growth, and weight gain, talk to your ob-gyn about getting tested for the condition.
7. You might have thyroid issues.
Your thyroid is a little butterfly-shaped gland that controls the hormones that regulate many systems in your body, including how fast you burn calories, how fast your heart beats, and yes, menstruation. Having too little thyroid hormone can cause your period to be super long and heavy, the OWH explains.
One in eight women will suffer from low thyroid function, or hypothyroidism, at some point in their lives, according to the OWH. Common symptoms of hypothyroidism include weight gain, fatigue, and hair loss, so if you're experiencing any of those, along with longer-than-normal periods, bring it up to your doctor, says Dr. Ross.
8. You have an underlying blood disorder.
Although rare, it's possible that extra-long periods are a sign of an underlying illness, like a hematologic (blood) disease, says Dr. Toth. Some of the underlying diseases associated with bleeding (like hemophilia or Von Willebrand disease) are genetic, so if you have this you likely already know about it.
If your periods last a noticeably long time and you've already been cleared for other conditions, it's worth checking in with your doctor about tests to rule out a blood disorder.
9. You have uterine polyps or fibroids.
"Uterine abnormalities, such as polyps or fibroids, can cause prolonged periods because they distort the endometrial cavity which can lead to increased blood flow," Dr. Toth explains. Basically, your body senses something in your uterus that isn't supposed to be there, and tries extra hard to get rid of it.
Polyps and fibroids sound scary, but they're pretty common—up to 80 percent of women will have at least one before they're 50, per the OWH. Important to note: Black women are two to three times more likely to have fibroids than white women, and the reasons for their increased risk are not well understood or well studied due to lack of representation of Black women in research, says Jodie Horton, MD, an ob-gyn and chief wellness advisor for Love Wellness.
For many people, these benign growths don't have any symptoms, and if they do, it's usually prolonged periods, says Dr. Toth. If you're concerned, your doc will likely recommend keeping an eye on them, but if they cause pain or grow very large, they can be surgically removed.
10. You have undiagnosed cervical cancer.
Abnormal vaginal bleeding—such as bleeding after vaginal sex or bleeding and spotting between periods—can be a sign of cervical cancer. Because cervical abnormalities can be detected through Pap and HPV tests, make sure you stay on top of those, and always tell your doctor about your family history of female cancers.
11. Your body's gearing up for menopause.
Menopause, which technically means you've gone 12 or more months without a period, hits women around age 50. However, your body starts the natural decline in hormones that leads up to menopause (a.k.a. perimenopause) as early as 35, says Christiane Northrup, MD, author of Women’s Bodies, Women’s Wisdom. When this happens, you may notice your periods getting longer or shorter, your cycle becoming more random, and other slight changes in your menstruation.
If you've ruled out everything else, and you're in your mid- to late-30s, your prolonged periods might simply be due to the natural process of aging. There is, however, such a thing as early menopause, which can affect women even in their twenties. So talk to your doctor if this runs in your family or if you're showing other signs of menopause, like a low sex drive or insomnia.
12. You’re under a lot of stress.
The body’s reaction to stress can change the levels of many hormones that cause your period to last longer than necessary, says Dr. Horton.
“Stress can cause delayed ovulation, causing your period to start later than expected, which can make your periods longer and heavier than usual,” she explains. “Identifying and eliminating stressors in your life will help regulate your periods over time. Meditation, getting enough sleep, and regular exercise are also effective ways to manage stress, she adds.
13. Medications might be messing with your cycle.
Medications such as anti-inflammatories, aspirin, or other blood thinners can also affect your menstrual cycle, says Dr. Horton. “Aspirin and blood thinners prevent blood clots but can increase the flow of your period,” she explains. “These medications can thin the blood so much that it causes your menstrual cycle to be heavy and last longer than usual.”
As such, it is important to take medicines as directed and if your period becomes heavier or prolonged, to contact your doctor, says Dr. Horton. You may need blood work to determine if you are taking too much medicine, and non-steroidal anti-inflammatories may be used to treat your heavy and prolonged periods.
14. You’re experiencing an ectopic pregnancy.
An unusually heavy period can be a sign of an ectopic pregnancy (a pregnancy found outside of the uterus, most commonly in the fallopian tubes), says Dr. Horton. Taking a pregnancy test can help you figure out if that's what's going on.
“If you have a positive pregnancy test and have pain and vaginal bleeding, you should be evaluated,” she says. “Your doctor will get blood work and a pelvic ultrasound to see where the pregnancy is located and, if it is ectopic, treat it with medicine or surgery.”
15. You may be pregnant and have placenta previa.
This type of heavy vaginal bleeding is actually unrelated to a period, though you might think it is one if you don't yet know you're pregnant. Placenta previa is a condition that happens during pregnancy where the placenta covers the cervix, explains Dr. Horton.
Patients will usually have heavy vaginal bleeding throughout their pregnancy and will need to deliver their baby by C-section. Take a pregnancy test and see your doctor to figure out the best treatment method.
16. You have adenomyosis.
Adenomyosis is a condition where the uterus lining, called the endometrium, is found in the muscular portion of the uterus. It is common in women who are in their 40s and have heavy, prolonged, and painful periods, says Dr. Horton. “With adenomyosis, the uterus is usually larger than average, and that leads to heavy, painful periods,” she explains. Your doctor may order a pelvic ultrasound or MRI to help make the diagnosis.”
It’s common to experience painful sex and frequent miscarriages with this condition, which is often difficult to diagnose until other possibilities are ruled out. And although there is no cure for adenomyosis, symptoms are treatable, says Dr. Horton, so talk to your doc about your options.
17. You have pelvic inflammatory disease.
Pelvic inflammatory disease (PID) is a condition caused by sexually transmitted bacteria, like that from gonorrhea and chlamydia, traveling from the cervix into the fallopian tube. PID can cause bleeding that is heavier than normal, spotting between menstrual cycles or spotting after sex.
“If you have abnormal bleeding and pain, get a pelvic exam and get tested for sexually transmitted infections,” says Dr. Horton. They can be treated with medication, which will stop the progression of PID too. Left untreated though, and PID can cause lasting issues with fertility.
18. Your weight could be impacting your period.
Obesity can affect your menstrual cycle, says Dr. Horton, because larger bodies produce excess estrogen, which can affect how often you have your periods and eventually cause you to stop ovulating regularly. “When you stop having periods every month, the lining of the uterus will become thick, and eventually shed, resulting in very heavy and prolonged bleeding.”
Losing weight (ideally 15 percent of your body weight) can help you regulate your periods, she says. Your doctor may also prescribe birth control pills or progesterone to help with the prolonged heaving bleeding.
When To See A Doctor
If your period lasts longer than seven days, or if it suddenly changes significantly in length for three or more cycles in a row, that warrants a call to your ob-gyn, says Dr. Toth. It's also worth seeing your doc if you're soaking a pad or tampon every hour for several hours or passing clots.
“Your doctor will ask how often you get your period, how many days it lasts, and do you have bleeding in between your period or after sex,” Dr. Horton adds. Your healthcare provider will probably ask about how heavy your periods are, any medications you're taking, if you've been tested for STIs, and if you're up-to-date on your Pap smears, she says—so make note of that info before your visit.
Your doctor may perform a pelvic exam to evaluate the cervix and the size and regularity of the uterus, as well as a pelvic ultrasound or hysteroscopy to see inside your cervix, uterus, fallopian tubes, and ovaries for any abnormalities. While this sounds scary, most causes of prolonged menstrual bleeding aren't a big deal and can be fixed or improved with the help of your doctor, Dr. Toth notes.
Emilia Benton is a Houston-based freelance writer and editor. In addition to Runner's World, she has contributed health, fitness and wellness content to Women's Health, SELF, Prevention, Healthline, and the Houston Chronicle, among other publications. She is also an 11-time marathoner, a USATF Level 1-certified running coach, and an avid traveler.
Averee Nelson is a New York City-based freelance journalist and copy editor specializing in social media trends, pop culture, and lifestyle. She holds an M.S. from the Columbia Journalism School, and her words can be found in Women’s Health, The List, Her Campus, and more. When she’s not writing, you can find her testing out new recipes in her kitchen, exploring the city, or reading (a lot).
