10 reasons your period might be longer than usual, according to doctors

Waiting for your period to end can be the worst. I remember being in my teens aggressively sucking on lemons and trying every other bizarre “home remedy” in the book (aka questionable old wives’ tales found on the internet) that promised to abruptly end my period in time for a highly anticipated date.

But impatiently checking for a cease to the bloodshed every time you hit the bathroom can be even more unnerving when your period has already been lingering longer than usual. Women usually menstruate for about the same number of days each month, so when a longer period pops up, it can feel like you’ll never stop bleeding.

What does it mean when you have an abnormally long period? We asked a bunch of gynecologists to clue us in.

How long is too long?

“Your menses should last between three and seven days, and the average is five,” board-certified ob-gyn Dr. Pari Ghodsi tells HelloGiggles. “Most people menstruate around the same amount of days each month, but even if there is variation, as long as it isn’t more than seven days, it is not abnormal.”

Dr. Jennifer Conti, another board-certified ob-gyn and co-host of The V Word podcast, says it’s not a big deal if your period varies by a few days every once in a while, but if it’s becoming a frequent occurrence, it’s worth a pause. “A ‘long’ period is one that lasts beyond eight days,” she explains. “If you’re routinely having periods that last eight days or longer, definitely see a provider to make sure you’re not losing too much blood.” That can potentially lead to anemia—a condition where you don’t have enough healthy blood cells bringing oxygen around the body, which can leave you feeling exhausted and weak, among other things.

Why might your period be lasting longer than usual?

First of all, it’s important to recognize that your longer-than-usual period might not be a period at all.

“Women can bleed and it’s not a period,” explains Dr. Felice Gersh, a board-certified ob-gyn and director of the Integrative Medical Group of Irvine. “A period is only when you ovulate, and you have a regular withdrawal [and] bleed from the rhythm of the hormones. You can have bleeding that comes around the time of the period, but it’s not a period.”

Any bleeding that happens that isn’t part of normal menstruation—such as bleeding mid-cycle, between periods—is called dysfunctional uterine bleeding. But sometimes this bleeding happens so close to the time when you’re expecting your period that you just assume it is your period.

So what causes that abnormal bleeding? The two most common explanations are pregnancy (yes, really) and hormonal imbalances caused by something happening in your life. But there are many, many other reasons why your period might be sticking around—some of which involve potentially serious hazards to your health.

Here are 10 of biggest reasons you might be having a “longer period”—or something that looks like one.

1Pregnancy

You might associate bleeding from your uterus with being baby-free, but the opposite can also be true. “The first thing you have to think about in a reproductive-aged woman is pregnancy,” Dr. Gersh explains. “Sometimes even a normal pregnancy can have bleeding in the first trimester. But a patient who has a tubal pregnancy or an impending miscarriage…can manifest with a so-called ‘longer period.’” (A tubal pregnancy, by the way, is a dangerous situation wherein the fertilized egg develops in your fallopian tube instead of your uterus.)

Dr. Gersh strongly advises anyone experiencing a suddenly abnormally long period to check their pregnancy status first and foremost. She adds that being on birth control doesn’t guarantee you’re not pregnant: “Everything has failure rates. Any kind of crazy bleeding, the first thing is rule out pregnancy, rule out pregnancy, and rule out pregnancy.”

2Miscarriage

It’s also possible that your “longer period” is actually an early miscarriage.

“One in five recognized pregnancies ends in miscarriage,” Dr. Conti explains. “That number often seems shocking to people because 1) there’s a lot of stigma around miscarriage, and 2) most miscarriages happen around five to seven weeks, before you may even realize you were pregnant. In these cases, people may think they just had a slightly delayed and really long period.”

3Hormonal imbalances caused by stress or life events

Your menstrual cycle is intimately interwoven with your hormone levels, Dr. Gersh explains, and your hormone levels can be affected by a number of external life happenings—emotional stress, physical illnesses, experimenting with some huge new diet, changes in your weight, changes in your sleep, or even just traveling across time zones. And when certain hormones are out of whack, it can impact your cycle and sometimes even cause you to skip ovulation one month.

“Maybe you didn’t ovulate, but you still made estrogen. So the estrogen does its thing: it causes the uterine lining to proliferate, to get thicker,” Dr. Gersh says. “You never ovulated, but it just got so thick it just started falling out like a tower of blocks that just starts to fall over when you make it too tall. So you get bleeding, but it’s not a period bleeding.”

It’s also possible that a lifestyle-induced hormonal imbalance leads to your body not menstruating during a given month; then, the following month, you’ve got more uterine lining than usual to expel from the body, resulting in a longer or heavier period.

So, yes, your stress could in theory lead to your period sticking around longer.

4Aging and perimenopause

“Our hormones change with aging,” Dr. Gersh says. So if you’re in your late thirties or into your forties, it’s actually quite normal for your menstrual cycle to start changing as your body begins perimenopause and gradually begins to make less estrogen. “The process of ovulating and the whole reproductive cycle is going to change with aging, so women should expect that their periods will change as they age,” she explains.

But Dr. Gersh adds that those changes should be consistent month to month: “It’s generally a gradual kind of process, so if you see an abrupt change with many days longer [on your] period and it’s heavier, then that should really spark some questions of what’s going on here.”

5Birth control side effects

“If you’re taking hormonal birth control and miss a dose, that can also affect your bleeding pattern,” Dr. Conti says. For example, the pill might have you only bleeding one day each “cycle,” but if you miss doses, you might see that amount of bleeding increase.

You might also experience longer or irregular periods just after an IUD insertion or sometimes just in general with IUD use depending on the type you’re using. “A copper IUD is known to increase the length of bleeding and also can increase menstrual cramps in some women. Those are things that are very well associated with it,” Dr. Gersh says. “And the other thing is the IUD could be migrating. It could be moving around in the uterus. It could be coming out. So you really want to check that.”

6Thyroid issues

The other way your hormones could be behind your extended period? Thyroid issues or thyroid disease, says double board-certified ob-gyn and perinatal consultant Dr. Kecia Gaither. The thyroid is a gland in your neck that produces hormones that control your metabolism and influence your menstrual flow. One in eight women deals with thyroid problems in her lifetime, and those with hypothyroidism (a condition where your thyroid isn’t producing enough of its hormones) can have irregular periods—whether that means they’re totally absent or abnormally long.

Some thyroid problems are mostly harmless, but there are other types (including hypothyroidism) that can lead to more serious health consequences, including heart problems, infertility, and even death.

7Something’s growing in or around your uterus

Now we’re getting into the tougher stuff. Dr. Ghodsi recommends contacting a doctor right away if your period is sticking around longer than it usually does because it might be a symptom of “structural problems with your uterus.” These include “uterine polyps (tissue growths inside of the uterus), uterine fibroids (non-cancerous muscle tumors that grow on the uterine muscle), adenomyosis (abnormal growth of the lining of the uterus into the muscle),” and more.

Polyps, fibroids, and other types of abnormal growth around or within the uterus can trigger a longer period—think of it like the body trying extra hard to expunge what it thinks are foreign objects or extra baggage in the uterus. It might also be that a uterine fibroid is growing in a particular position that’s “impacting on the uterine cavity,” Dr. Gersh explains, which might “change the type of bleeding, the quantity of bleeding, the length of bleeding,” or otherwise mess with your period.

Many structural issues with the uterus will necessitate treatment: “They can not only cause heavy, prolonged menses (menorrhagia), but they can additionally impair fertility, pending their location,” Dr. Gaither says.

8Polycystic ovary syndrome

PCOS is the most common endocrine disorder in women, according to Dr. Gersh, and one of the most common causes of infertility in women. It’s named because it often causes cysts to be growing on a person’s ovaries. According to the Mayo Clinic, the most common sign of PCOS is an irregular period—including an abnormally long or heavy one.

9Cancer

A longer period alone is not a typical indicator of cervical or uterine cancer, Dr. Gersh says. Cancer won’t usually present itself via just an extra few days of otherwise normal bleeding—but it’s not impossible. “You can have cervical cancer that’s up in the canal in the cervix, and it’s rubbing in some fashion when you’re having your period, and it causes more bleeding. That would be atypical, but it’s never impossible. So any type of abnormal bleeding should be evaluated. It’s always better to be cautious than not.”

10Blood disorders

Blood disorders like Von Willebrand disease (a genetic condition where you’re missing an important protein that makes your blood clot, preventing excessive bleeding) or idiopathic thrombocytopenic purpura (in which you’re low on the blood cells that do the clotting) can lead to having heavier or longer period than typical menstruators. But if you’ve got a blood disorder like that, you were probably born with it and already know about it—it usually wouldn’t suddenly start affecting you during a random phase in your adult years. It is possible to acquire a blood disorder, but it’s uncommon.

“If somebody acquired a blood disorder like leukemia, then their body may have low platelets, or they can develop a condition,” Dr. Gersh says. “So your clotting mechanism is not working properly, and then you would bleed usually more heavily and longer.” Again—this is pretty rare, but it’s good to be aware of what’s within the realm of possibility.

So what should you do?

“If your period varies by a few days every once in a while, that’s usually not a big deal,” Dr. Conti says. “But if you start noticing that your period is becoming routinely longer or heavier, that’s a reason to check in with your provider and make sure there’s not an underlying cause for the change.”

If your period lasts longer than usual just once or twice and you’re otherwise healthy (i.e. you got checked and don’t have any of the above-mentioned more serious conditions), there’s no real danger to your health from a few extra days of bleeding. Dr. Gersh does, however, recommend thinking through your habits and life situations that might be triggering a hormonal imbalance that’s affecting your period. “Think of this as a warning sign that something needs improvement,” she says. “Take a survey of lifestyle choices, stress management techniques, job and family relationships, and overall health status. Make improvements as possible.”