Here's how to tell if your nausea, bloating, or fatigue could be period flu or something more serious—and how to manage it.
What Is Period Flu? Here’s What Expert Doctors Want You to Know
Updated on Mar. 13, 2025
About the experts
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Highlights
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Period flu isn’t a formal medical condition—but providers are increasingly hearing this term from patients to describe symptoms they experience right before or during their period, explains Meghan McGrattan, MD, OB-GYN, a fellowship-trained gynecologic surgeon and physician at the University of Toronto.
Estimates vary, but premenstrual syndrome (PMS) likely affects at least half of women worldwide, according to a 2024 review of research published in Frontiers in Psychiatry. The most common symptoms include mood changes, anxiety, bloating, cramping, breast tenderness, and headaches. But period flu, an unofficial type of PMS, is considered a bit more severe, causing symptoms that mimic a mild flu, Dr. McGrattan says.
However, these symptoms should not be confused with symptoms of the actual influenza virus or other viral illnesses such as Covid, says Christine Gerber, MD, an OB-GYN at Atlantic Health System in New Jersey. For instance, period flu may cause chills and cause you to feel feverish, but, Dr. McGrattan explains, “Importantly, in a classic period flu, there would be no true fever.”
Period flu symptoms
Period flu symptoms can begin any time after ovulation, the point during a woman’s cycle when the ovary releases an egg. But generally, they’re most noticeable in the days leading up to your period and ease up within a few days after menstruation begins.
The cause of PMS symptoms likely comes down to the changes in hormones that occur during this part of your cycle, Dr. Gerber explains. After ovulation, estrogen and progesterone levels drop—and as your period begins, prostaglandins are then released. Prostaglandins are what help your uterine lining shed, often causing a classic PMS symptom: cramping.
These changes can cause other typical PMS symptoms, such as bloating and mood swings. But hormones are likely behind period flu symptoms, too, Dr. McGrattan says. These might include:
- Body aches
- Joint and muscle pain
- Nausea or vomiting
- Digestive disruptions like diarrhea
- Fatigue or low-energy
- Headaches
- Chills and feeling feverish
“Intuitively, these are all very similar to how we experience a mild flu, hence the term,” she says.
However, remember that period flu does not cause an actual fever. You may experience fever-like symptoms, such as feeling warm and flushed or having chills and cold sweats. But “the rise in temperature seen in the menstrual cycle is slight,” Dr. Gerber explains. “If there is a fever—a temperature reading of 100.4 degrees Fahrenheit or above—care should be sought with a healthcare professional.”
Is period flu normal?
Period flu symptoms shouldn’t be considered “normal,” says Felice Gersh, MD, a board-certified OB-GYN and integrative medicine doctor in Irvine, California. “The menstrual cycle is a vital sign of well-being,” she says.
Still, it’s not clear why some people may get period flu symptoms—or why some people experience them more intensely than others, Dr. McGrattan says. “But I think it’s important to keep in mind that while the ‘period flu’ may be transient and annoying for some, for others, these symptoms can be representative of severe PMS or even PMDD (premenstrual dysphoric disorder).”
Period flu causes
“The symptoms experienced by period flu sufferers are most likely due to the hormonal fluctuations of the menstrual cycle,” Dr. McGrattan says. And there are a few different ways hormonal changes can affect how you’re feeling.
Drop in estrogen and progesterone
“Right before our periods start, we experience a sharp drop in estrogen and progesterone,” Dr. McGrattan says. “[This] can trigger inflammation, affect pain perception, and even influence immune system function, which can contribute to that ‘flu-like’ feeling.”
Release of prostaglandins
“Prostaglandins are one of the reasons women suffer from painful periods,” Dr. Gerber explains.
The drop in progesterone is what signals the uterus to shed the endometrium—the inner layer—causing a period, Dr. McGrattan says. When this occurs, prostaglandins are released to help contract the uterus and expel menstrual blood.
These uterine contractions are why cramping is such a common symptom of periods, but prostaglandins can also cause body aches and gastrointestinal upset, such as nausea and diarrhea, Dr. Gerber says.
Central nervous system response
According to 2022 research published in StatPearls, prostaglandins can also affect your central nervous system, which may contribute to feverish feelings and increase your pain perception.
Drop in serotonin levels
“The decline in estrogen [before menstruation] can lower serotonin,” explains Christy Tabit Evans, MD, a board-certified OB-GYN at Almond OBGYN in Los Angeles.
Serotonin is a neurotransmitter that’s involved in many bodily functions, including mood regulation, sleep quality, and digestion. Declining levels before and during menstruation may be responsible for “mood swings” associated with periods, but might also introduce period flu symptoms thanks to digestive upset and sleep interruptions.
Lifestyle factors
Certain lifestyle factors can affect how your hormones function, Dr. Gersh explains. This could lead to more dramatic fluctuations in your estrogen and progesterone levels leading up to menstruation or cause an overproduction of prostaglandins, for instance.
Lifestyle factors that could contribute to hormonal imbalances or disruptions include:
- Poor sleep
- Unmanaged stress
- Smoking
- Heavy alcohol use
- Nutrient deficiencies
- Lack of physical activity
These behaviors can also contribute to increased inflammation in the body, which may affect hormone function and cause severe or unusual PMS symptoms, such as period flu symptoms, Dr. Gersh explains.
How to manage period flu symptoms
Dr. McGrattan says that her go-to tips for managing period flu symptoms include:
- Taking anti-inflammatory medications (like naproxen) to relieve pain and reduce the inflammation that contributes to period flu symptoms.
- Heat therapy with heating pads to relieve muscle pain and abdominal cramps.
- Hydration and rest to support your body through symptom flare-ups.
- Physical activity.
“Regular physical activity is associated with improvements in PMS symptoms, but this can be difficult to do when you’re in the thick of the period flu,” she says. “Low-impact movement like walking or stretching may help to improve circulation and ease cramps.”
If you’re having difficulty managing period flu symptoms with these first-line approaches, there are some other strategies that may help, she says. However, the efficacy and level of evidence can vary. More research is needed about period flu, and what works for one woman might not offer relief for another.
Hormonal birth control pills
“Also referred to as combined oral contraceptives (COCs), these are one of the most effective options we have for managing severe PMS and ‘period flu’ symptoms,” Dr. McGrattan says. “They work by stabilizing hormone levels, reducing prostaglandin production, and sometimes eliminating periods altogether.”
She says that COCs have been extensively studied in this area, and there is strong evidence that they work to reduce these symptoms and are considered a first-line management option by most OB-GYN professional societies.
“Other contraceptives like the vaginal ring and injectable medroxyprogesterone acetate (most commonly sold as Depo-Provera) also show some efficacy at reducing PMS symptoms, but less reliably than the COC,” she notes.
SSRIs
“Although not specifically studied for ‘period flu’ per se, for people whose symptoms lean more heavily towards mood changes and fatigue, selective serotonin reuptake inhibitors (SSRIs) could be considered, and are strongly supported by evidence and frequently used in treating PMS and PMDD,” Dr. McGrattan says.
Supplements
“There is moderate evidence to suggest that calcium supplementation may reduce some of the physical and emotional symptoms related to PMS like fatigue or mood swings,” Dr. McGrattan says. “Similarly, Vitamin B6 and magnesium have both been studied in this area and show some moderate effect for treating symptoms like bloating, mood disturbances, and fatigue, but they should probably not be the first line approach for those experiencing severe symptoms.”
Omega-3 fatty acids (such as fish oil supplements) have anti-inflammatory properties that may also help with period flu symptoms and pain, says Dr. Tabit Evans. In addition: “Vitamin D can help with fatigue and immune function.”
Dr. McGrattan says that there have been some studies looking at the impact of chasteberry on PMS symptoms, and it shows moderate efficacy for reducing symptoms of mood swings and breast tenderness. “However, it does not appear to impact flu-like symptoms such as fatigue, bloating, or body aches.”
Another word of caution: “There are many other herbal remedies available which are marketed towards reducing PMS symptoms, but unfortunately, they do not have enough high-quality evidence to recommend their use in general.”
Stress management
Stress triggers an inflammatory response in the body, which can make typical PMS symptoms feel even worse—and potentially trigger flu-like period symptoms like stomach problems and body aches.
Dr. Tabit Evans recommends practicing stress management techniques such as meditation, deep breathing, or whatever helps you relax. Lowering stress can help reduce bodily inflammation—alleviating your symptoms—while also helping to regulate mood swings.
Dietary changes
Cutting back on caffeine, alcohol, and processed foods may help period flu symptoms, but there’s limited evidence to support this, Dr. McGrattan says. “Still, some patients do find symptom relief with an anti-inflammatory diet.” (Plus, reducing your intake of caffeine, alcohol, and processed foods in general can have positive effects throughout your body.)
“This might include reducing refined sugars and trans fats and emphasizing omega-3 fatty acids, leafy greens, berries and fruits, whole grains, and fermented foods like yogurt and kimchi to support gut health,” Dr. McGrattan says. “And, of course, ensuring proper hydration!”
Track your cycle
Tracking your symptoms and how you feel throughout your cycle can help support these period flu management techniques, according to Dr. Gerber. If you’re nauseated several days every month—and you know to expect that—you won’t be caught off-guard when it happens again.
It can be very easy to forget what you were feeling and when from month to month, which is why writing it down can be so helpful. Apps like Flo and MyFLO make this easy. These can help you collect enough data to know what your norm is.
By the way, some people who have an intrauterine device (IUD) find that they don’t have the bleeding that would mark their period. An IUD does not prevent you from ovulating, explains Dr. Gerber, so you can still get PMS symptoms. That makes tracking all the more important—whether you bleed or not.
Period flu prevention
All the healthy lifestyle habits you’ve been told are important for your general well-being will also influence your PMS symptoms, says Dr. Gersh. These are often dubbed as self-care:
- Good sleep hygiene (e.g., going to sleep at a set time each night)
- Staying off electronics before bed
- A diet of whole foods (produce, healthy fats, whole grains)
- Staying physically active
- Spending time in nature
Taking care of yourself in these ways can help lower stress and inflammation so you can feel better as soon as next month, she says.
“Ultimately, although the ‘period flu’ may not be a formal medical diagnosis, it is absolutely real for many people,” Dr. McGrattan adds. “ The good news is, you don’t have to just suffer through it—there are effective treatments, and a personalized approach can make a big difference.”
When to see a doctor for period flu symptoms
If period flu symptoms are severe or impact your quality of life, our experts recommend seeing a doctor. “Don’t take these symptoms for granted—you deserve pain-free, symptom-free periods,” Dr. Tabit Evans says.
An OB-GYN can review your full symptom history and screen for PMS and PMDD, as well as underlying structural conditions like endometriosis, which are often missed in the discussion of challenging periods, Dr. McGrattan says.
“If your review of symptoms suggests a different underlying disorder—like an autoimmune condition—they would also be able to refer you to another specialist provider.”
She says your doctor may also explore medication options, including prescriptions to support your periods in general, like a COC, or medications to target specific symptoms. “They should also discuss lifestyle counseling to optimize sleep, nutrition, stress management, and exercise.”
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Sources
- Frontiers in Psychiatry: “Premenstrual syndrome: new insights into etiology and review of treatment methods”
- StatPearls: “Prostaglandins”
