Maybe you’re new to this whole period thing. Or perhaps you and your period have been partners in bloody crime for years, but it's changing things up on you. Either way, you might be wondering: How long does a period last for most people?
There are actually a lot of different period lengths that doctors consider normal, Lauren Streicher, M.D., an associate professor of clinical obstetrics and gynecology at Northwestern University Feinberg School of Medicine, tells SELF. That doesn’t mean you should just write off what seems like a weirdly short or long period. It’s worth paying attention to how long your period sticks around, since an extremely short or long period can be a sign that something’s up with your health.
Even if you’re well-acquainted with your period, let’s take a quick second to go over the basics of how exactly it works.
During your menstrual cycle, your uterine lining builds up to prepare for possible pregnancy. To do this, your ovaries start releasing more estrogen to grow your uterine lining so it’s a nice, plush home for a fertilized egg to latch onto. After one of your ovaries releases an egg around the middle of your cycle, your estrogen levels drop, but your levels of the hormone progesterone rise to thicken that uterine lining so it’s even more hospitable for a potential pregnancy.
If you don’t get pregnant that month, your levels of estrogen and progesterone start to fall. Very low levels of estrogen and progesterone tell your body to shed that uterine lining and, as a result, you get your period.
Keep in mind that this is all very different if you’re using a hormonal birth control method, which we’ll get into in a bit.
There’s no hard and fast rule for how long your period should last, but anything between two and seven days is generally considered normal.
Congratulations, you blessed people who have periods that only hang around for two days: You’re on the lightest end of the period spectrum, Amber Bondurant-Sullivan, M.D., an ob/gyn at The Ohio State University Wexner Medical Center, tells SELF.
On the flip side, it’s also normal to have a period that lasts a full week, according to the American College of Obstetricians and Gynecologists. But once your period starts edging past seven days, you’re technically in menorrhagia territory. Menorrhagia happens when your period is either abnormally long, abnormally heavy, or both, according to the Centers for Disease Control and Prevention (CDC).
If your cycle is shorter than two days or longer than seven, your doctor may want to dig a little deeper to see what’s going on—especially if what you’re dealing with is different from your usual, or if you’re bleeding very heavily or lightly, Dr. Streicher says.
A few health conditions that affect your ovaries or your hormones can cause extremely short periods.
For the record, it’s considered pretty normal to have shorter, lighter, or even non-existent periods when you’re on hormonal birth control. No matter which kind of hormonal birth control you choose, it will contain progestin, which thins your uterine lining and can thus result in a less intense period. “This is less concerning and is an expected result of the birth control,” Dr. Bondurant-Sullivan says.
If you’re not using hormonal birth control and your period is shorter than two days, it could be a sign of one of the following conditions:
Premature ovarian insufficiency: Also known as premature ovarian failure, this is the loss of normal function of your ovaries—either because they don’t produce enough estrogen or don’t release eggs often enough—before you turn 40, according to the Mayo Clinic. It can happen if you’re born with a genetic disorder that affects your ovaries, have been through treatment like chemotherapy or radiation, or have an autoimmune condition where your body attacks your ovarian tissue. The cause could also be completely unknown.
No matter the underlying reason, premature ovarian insufficiency can lead to short, irregular, or completely MIA periods. You might also deal with symptoms of estrogen deficiency, which are common during menopause, like hot flashes, night sweats, vaginal dryness, irritability or a harder time concentrating, and lowered libido.
Hypothalamic hypogonadism: This condition happens when your ovaries produce little or no gonadotropin-releasing hormone (GnRH), follicle stimulating hormone (FSH), and luteinizing hormone (LH), according to the U.S. National Library of Medicine. These sex hormones are all heavily involved in regulating your menstrual cycle.
Normally, your brain’s hypothalamus releases GnRH, which stimulates your pituitary gland to let loose some FSH and LH. The former triggers egg-containing sacs (follicles) on your ovaries to start maturing for potential fertilization, while the latter prompts one of those follicles to actually burst and release an egg. Hypothalamic hypogonadism happens when there’s a change in this chain of hormone releases, so you wind up with very short periods or no periods at all. This can happen due to things like having very low body fat or not taking in enough calories, Dr. Bondurant-Sullivan says, which is why it’s often seen in athletes who train intensely and women with eating disorders.
Hyperthyroidism: Also known as having an overactive thyroid, hyperthyroidism is a condition where your thyroid gland (a butterfly-shaped gland in your throat) makes too much of the hormone thyroxine, according to the Mayo Clinic. This speeds up your metabolism (how your body uses energy), which can cause a host of symptoms like shorter periods, sudden weight loss, an irregular heartbeat, and irritability.
A range of things can cause you to have longer periods than normal, and many of them are reproductive health conditions.
While hormonal birth control tends to make your periods shorter, the non-hormonal copper IUD can sometimes make your period longer or heavier, especially when you first start using it, Dr. Bondurant-Sullivan says. For some people switching from a hormonal birth control to the copper IUD, your period may just seem longer since it was shorter on your previous birth control method. But for others, the copper in the IUD can be irritating and actually lead to a heavier period.
Not using the copper IUD? There are a few health conditions that could be behind longer periods:
Adenomyosis: Adenomyosis happens when endometrial tissue that normally lines your uterus grows into the organ’s muscular walls, according to the Mayo Clinic. There, the tissue acts like it normally would—it gets thicker, breaks down, and bleeds during your cycle, and can cause wildly painful, heavy, long periods.
Cervical polyps: Cervical polyps are growths that just show up wherever they feel like it—in this case, they hang from your cervix. They’re typically non-cancerous but can cause long or heavy periods, spotting, bleeding after sex, or a discharge made up of white or yellow mucus.
Endometrial hyperplasia: This condition happens when your endometrium becomes too thick, usually due to a lack of ovulation that results in insufficient progesterone production. Then, your body doesn’t get the signal to shed your uterine lining when it should, ACOG explains, so the lining can just continue to build up in response to your body’s estrogen. When it finally sheds, that overgrowth can result in a longer period.
It’s worth noting that sometimes endometrial hyperplasia can lead to cancer, because the endometrial cells in that built-up lining get packed together and may act abnormally, ACOG says. Even though many other conditions on this list are way more likely to be behind your long periods, this shows why it’s always worth seeing a doctor if something with your body seems strange.
Polycystic ovary syndrome (PCOS): PCOS involves a hormonal imbalance that can have a similar result to endometrial hyperplasia: The lining of your uterus can continue to build without shedding for way too long. When your period does finally decide to arrive, it can be overwhelmingly long or heavy. In addition to that, you might experience symptoms like excess face and body hair, severe acne, and male-pattern baldness, according to the Mayo Clinic.
Uterine fibroids: Uterine fibroids are non-cancerous tumors that grow in and on the muscle of your uterus. While it’s possible to have fibroids without symptoms, a heavy flow that lasts for more than seven days is a common sign of this condition, Dr. Streicher says.
Fibroids can also cause tremendous pain, pelvic pressure, frequent urination, trouble fully emptying your bladder, constipation, and even back or leg pain, according to the Mayo Clinic. Depending on their location and severity, they could also interfere with getting pregnant or carrying to term.
Uterine polyps: These are growths that pop up in your endometrium, per the Cleveland Clinic. Uterine polyps are usually non-cancerous, but they can cause frustrating symptoms like longer, heavier, or irregular periods, along with spotting. Much like fibroids, they may also contribute to problems getting or staying pregnant.
A bunch of things in life, including your stress levels and diet, can interfere with your cycle. If it’s off one month and then goes back to normal, you’re probably fine, Dr. Streicher says.
But if the strangeness continues, or you’re realizing what you thought was normal actually falls into either the “too long” or “too short” camp, it’s time to talk to your doctor.
They will likely ask you a bunch of questions about your period, including how long it lasts, how much you bleed, and whether you notice a lot of blood clots (passing clots larger than a quarter is a classic sign of menorrhagia), Dr. Bondurant-Sullivan says. They’ll probably also do a pelvic exam to feel around for any noticeable abnormalities and potentially order a pelvic ultrasound, blood tests, or both to try to figure out what’s going on, she says. They may also conduct more specific testing based on what they suspect is happening.
All together, this testing should help your doctor make a diagnosis and, from there, land on a treatment that gets your period right within that normal range.