What Causes Irregular Periods, and When Should You Worry?

What Causes Irregular Periods, and When Should You Worry? Whether you’re dealing with unpredictable timing, too-frequent bleeding, or disruptive pain, irregular periods can be a huge drag—one that up to 25% of people who menstruate have to live with. And who wouldn’t get tired of pregnancy scares, hanging back on vacations, or calling off work to curl up in bed with a heating pad?

If your period is erratic or significantly uncomfortable, it’s worth investigating what’s causing that. Maybe you’re a few lifestyle tweaks away from regularity—or maybe what’s going on with your menstrual cycle is your body’s way of flashing the Check Engine light.

Before moving any further, let’s establish what a “normal” period is—which can look a bit different from person to person. A menstrual cycle begins on the first day of bleeding and ends on the next cycle’s first day of bleeding. A regular cycle lasts between 21 to 35 days for most people, including two to seven days of bleeding as you shed your uterine lining.

Not all discomfort is cause for concern—in fact, it’s pretty normal to feel mildly achy or queasy. According to the American College of Obstetricians and Gynecologists (ACOG), more than half of people who menstruate experience one to two days of dysmenorrhea, or menstruation-related pain, as a part of their cycle—but that pain is a typically mild cramping sensation, sometimes accompanied by nausea, diarrhea, headache, and dizziness that occurs right before or during your actual period.

If all of that sounds like the kind of period you wish you had—or is even just noticeably different from your own personal experience—there’s help out there! SELF talked to experts about what could be causing your irregular periods and when it might be time to speak with a medical professional about what’s going on.

An irregular period, in essence, deviates from the “normal” pattern outlined above in one or more ways, per ACOG. It could be a period that comes with debilitating pain; it could be a period that stretches into weeks instead of taking place over two to seven days; it could be heavy bleeding that requires you to change your tampon hourly, as opposed to every four to eight hours; it could be a period that doesn’t happen on a fixed schedule. If any of these scenarios sounds familiar—a regular irregularity, basically—then you might be dealing with an irregular period. If that’s impacting the way you live your life, don’t worry. Once you determine what might be causing your irregular period, you’ve got options for getting things back on track.

There are a lot of factors that can contribute to an irregular period, but more potential causes also means there are more potential solutions for whatever’s throwing you off course. Here are a few things to consider:

• Age. Julia Cron, MD, FACOG, vice chair of the obstetrics and gynecology department at Weill Cornell Medicine and New York-Presbyterian Lower Manhattan Hospital, tells SELF that both adolescents and perimenopausal people are more likely to experience irregular periods. This is due to hormonal changes as they enter and exit the phase of their lives when they get a period at all. “Eighty percent of people will have ‘normal’ periods three years after menarche,” which refers to a person’s first period, she says.
• Stress. As if having an irregular period wasn’t stressful enough! An excess of cortisol, a hormone your body produces when you’re stressed out, can be enough to push a period back by a few days—or even cause you to skip one entirely, per the Cleveland Clinic.
• Changes in weight. People experiencing significant weight gain or loss can experience irregular periods, especially if a person is dealing with an eating disorder like anorexia or binge eating.
• Certain illnesses or a new medication, like hormonal birth control, steroids, or blood thinners, can also affect your period. “Any new medications can throw your cycle off for a little bit,” Kelsey Kossl, MD, a gynecological surgeon at NYU Langone, tells SELF. But any medical event has the potential to alter your period temporarily. “Getting sick, getting new vaccinations—those are things that stimulate our immune system,” Dr. Kossl says. “That could lead to a little bit of change in the timing or quality of our period for that month.”
• Sudden increases in exercise. If you’re training for a marathon or similarly ramping up the amount you’re working out, intensive exercise can set your period out of whack or stop it altogether, even if you have been historically “regular.”
• Hormonal imbalances, including ones caused by thyroid issues like hyperthyroidism or hypothyroidism, can also affect your period. That’s because hormones like estrogen and progesterone are what trigger different phases of the menstrual cycle.
• Bleeding disorders. Dr. Cron points to von Willebrand disease, a clotting disorder, as a particularly common example of an inherited blood disease that can cause abnormally heavy bleeding during one’s period.
• Structural issues in the reproductive system. Fibroids, cysts, polyps, and other conditions that can affect menstrual flow may also cause irregular periods—but more on that later.

There is one pretty glaring medical issue that can interrupt your period: pregnancy. If you’ve had unprotected sex, or PIV intercourse in general, and your period is late or missing, you should take a pregnancy test to rule that out completely. If you can’t tie your irregular period to pregnancy or any recent life events, medication changes, or lifestyle habits, something else could be at play healthwise.

AnnaMaria Maples, MD, an ob-gyn at Emory University School of Medicine inAtlanta, tells SELF that three or more months of irregular menstrual bleeding is a red flag that could indicate a bigger health issue, like a hormonal imbalance.

“It’s important to have regular exposure to progesterone and estrogen,” Dr. Maples says. Ordinarily, that exposure would come from your own body’s production of those hormones. “Naturally, ovaries make these hormones, and together they impact the menstrual cycle.”

The specific way that your period is irregular can also tell you something about what the potential cause could be. “If you’re skipping many months between periods, that can sometimes be a sign of PCOS, or polycystic ovary syndrome,” says Dr. Kossl. “For those patients, sometimes when they’re skipping months, when their periods actually do come, they can be heavy or prolonged.” Dr. Kossl also notes that PCOS can be tough to diagnose and that people with the condition often experience other symptoms outside of irregular periods. If you’re experiencing frequent ovarian cysts, hair growth that feels outside of your norm, acne, rapid weight fluctuations, prediabetes, or difficulty getting pregnant on top of an irregular period, consider talking to a doctor about getting tested for PCOS, which could mean undergoing a pelvic exam, some blood tests, and/or an ultrasound, per the Mayo Clinic.

Dr. Cron says that debilitating menstrual pain also often indicates a bigger issue. She points to endometriosis—a condition that Lena Dunham, Halsey, and Padma Lakshmi have all spoken about living with—as a particularly excruciating cause of menstrual irregularity, as well as other symptoms, like pain during sex, fertility issues, stomach problems, and persistent fatigue, among others.

According to Dr. Kossl, if your period is causing you significant discomfort of any kind—or you just feel like something is off—you should discuss that with a medical professional. “If anybody’s experiencing changes to their periods that are resulting in bothersome symptoms, that’s always worth addressing,” she says. “That doesn’t necessarily mean that there’s something wrong or abnormal, but that’s what we’re here for as providers. People shouldn’t have quality of life issues secondary to menstrual periods.”

If a visit to the doctor is an emergencies-only situation for you, the symptoms that can come with issues like PCOS and endometriosis are big signs that it’s time to talk to a health care provider. That means if you’re experiencing lots of pain (especially during sex), persistent fatigue, fertility issues, adult acne, or hair growth that feels abnormal for you, and irregular periods, that’s your signal to make an appointment if you can.

So is nonstop bleeding—according to the Centers for Disease Control and Prevention, you should see a doctor if you are passing period blood clots that are the size of a quarter or larger, or bleeding through a pad or tampon in less than two hours. “In that case, we would do evaluations to see if there’s anything structural in the uterus, such as fibroids or polyps,” Dr. Kossl says. “For [people] who might be a little bit closer to menopausal range, we’d also be looking at some safety checks to make sure that we’re not seeing any precancerous or cancerous tissue that is presenting with abnormal bleeding.”

Outside of a diagnosis of and treatment for a specific medical issue, if you have irregular periods that aren’t symptomatic of other conditions, you still have options for evening out your flow and cycle.

One is to explore using a hormonal form of birth control, like the pill, a hormonal IUD, or the birth control implant—all of which can help to regulate your period. Changing from one of these methods to another could also be the answer. If you’ve been spotting since you started taking a progestin-only pill, you could try a combination pill, which contains estrogen and progestin, or consider having an IUD inserted.

Hormonal birth control, according to Dr. Cron, can also be a solution if you’re trying to stop your period altogether. “Menstrual suppression is safe and effective,” she says. “It can really be transformative for people: athletes that don’t want to get their periods, patients that have developmental delays and maybe can’t manage their own hygiene, transgender patients for whom getting their period is really dysphoric.”

If you and your health care provider determine that your irregular periods are likely due to stress, look into stress management strategies like breathing exercises, moving your body on a regular basis, and making sure you get as much regular, deep sleep as possible.

Hopefully, getting some answers about what’s going on with your irregular periods is a major step into decreasing your overall stress too—and feeling a lot more aware and in control of your body and health.

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