8 Reasons Why Your Period Is So Bad

Photographed by Megan Madden.
With painful periods, your one salvation is that they do, in fact, end relatively quickly. But, for people with heavy periods — which can last for over a week at a time — even that isn't necessarily the case.
"The biggest thing I notice is that women adjust to what is normal for them," says Timothy Ryntz, MD, a gynecologist at NewYork-Presbyterian Hospital. "Because these changes happen gradually over time, many people learn to adapt to what probably isn't a healthy amount of flow."
So what is and isn't healthy? It comes down to both the length and amount of your bleeding, Dr. Ryntz says, which can be kind of hard to keep track of. But the general rule of thumb is that, if you're bleeding for more than seven days or you're going through more than one pad or tampon per hour for a few hours, that's considered a "heavy" period. Some of us just naturally bleed more than others, but bleeding this much usually indicates that there's something else going on.
And that "something else" could be a lot of different things: Basically, anything that makes your endometrial lining thicker or interferes with the way it leaves your body will cause more bleeding. That includes anatomical issues (such as noncancerous tumors in your uterine lining), as well as medications, (such as progesterone-only birth control), which affect the hormones responsible for building up your lining.
Not all heavy periods are cause for concern, but there are some cases in which you're going to want to check in with your doctor. If you are bleeding for more than seven days (and especially if you've done so for at least three cycles in a row), it's time to call your doc. And if you have any symptoms of anemia — extreme fatigue, nausea, shortness of breath — along with heavy bleeding, get yourself some medical attention ASAP, Dr. Ryntz says.
Ahead, we've collected a few of the most common causes of heavy periods, and what you should know about 'em.
Read These Stories Next:
1 of 8
Uterine polyps

These are little (usually) noncancerous growths that sometimes show up along the inner wall of your uterus. Along with unpredictable periods, they can also cause you to have an unusually heavy flow, Dr. Ryntz says. Unless your doctor has determined that your polyps are cancerous or precancerous, smaller polyps don't need to be removed unless they're causing really unbearable side effects or making it difficult for you to become pregnant.
2 of 8
Uterine fibroids

Fibroids are bundles of muscle cells and tissues that grow along and within the uterine wall. They tend to cause a feeling of "fullness" in your pelvic region, pain during sex, and low back pain along with long, heavy periods. These aren't cancerous, but they are annoying and painful. They can sometimes cause infertility, bleeding between your periods, and periods so heavy that you develop anemia, at which point your doctor may recommend that you get them removed.
3 of 8

"[This is] a condition in which cells that make up the endometrial lining grow within the wall of the uterus," Dr. Ryntz says. "That enlargement [of the uterus] can cause heavier periods." Those endometrial cells go on with their lives as normal, growing and shedding every month. But your periods will be both heavy and painful. Hormonal birth control can sometimes help reduce the severity of your periods (or eliminate them altogether). But if your symptoms are serious enough, your doctor may recommend a hysterectomy to remove your uterus.
4 of 8

This is a pretty wide category, it turns out. The two most obvious ones are blood-thinners (which, obviously, make it harder for your blood to clot) and hormonal birth control. Although you're more likely to have lighter periods when you go on birth control, there are some forms — especially the progestin-only injection and copper IUD — that are known to make periods heavier.
5 of 8
Blood clotting issues

These certainly aren't the most common causes of heavy periods, Dr. Ryntz cautions, but they do happen. For instance, Von Willebrand disease, an inherited condition that makes it harder for your platelets to stick together to clot your blood properly, can make your periods especially heavy.
6 of 8
Missed period

Just because you missed a period doesn't mean your endometrial lining stops growing — it just means that it keeps building up until your period finally does show up, Dr. Ryntz says, at which point, everything will shed. Although that's not technically a heavy period (it's more like two or three normal periods at the same time), it will definitely seem heavier because you're getting rid of more than one period's worth of lining at once.
7 of 8
Polycystic ovary syndrome (PCOS)

In general, PCOS causes irregular periods rather than specifically heavy periods, Dr. Ryntz explains. But, if your PCOS causes you to have extremely long cycles or skip a period here and there, that would make your next period feel heavier.
8 of 8

If you have endometriosis, that means that your endometrial lining is growing outside of your uterus (often around your reproductive organs). Although endometriosis doesn't usually make you bleed more, it does make your period a lot more painful, Dr. Ryntz says, so you might think you're going through an especially heavy period.