Feeling sick before your period could be a sign of menstrual flu

Does a woman’s immune system weaken at certain times in the menstrual cycle? I’ve always noticed that if I get sick, it’s almost always just before my period.

Experts say that while there is not enough data to prove that women are more likely to feel sick before menstruation or while menstruating, there is some evidence that this is possible.

Emerging research suggests that the immune system can become unstable during this time, sometimes exacerbating symptoms of underlying chronic illnesses or creating new symptoms that some women may mistake for signs of a new illness.

Just before menstruating, for example, some women report symptoms usually associated with the flu, such as body aches, malaise and even fever.

So-called menstrual flu is not caused by an actual pathogen, said Dr. Taraneh Shirazian, gynecologist at NYU Langone Health. But it could be the result of a woman’s immune response to the natural inflammation present when the uterus contracts and releases cells. “It’s how her body apprehends inflammation,” she explained.

According to Shirazian, the cause of these symptoms can also be hormonal. Luteinizing hormone, or LH, rises in levels just before ovulation and drops sharply when menstruation begins. As LH levels change, people may experience fatigue, bloating, headaches, and nausea. “Some women go through this every cycle, every month, with really aggressive symptoms,” said the gynecologist.

In a 2018 review in partnership with the Clue app, which tracks the menstrual cycle, researchers observed that in women who had certain underlying conditions — such as irritable bowel syndrome, epilepsy and autoimmune diseases — they felt that disease-related symptoms sometimes they got worse during ovulation, got better a week later, and got worse again during menstruation.

For Sabra Klein, a microbiologist at the Johns Hopkins Bloomberg School of Public Health (United States), this could be the result of the rise and fall of hormone levels and changes in the immune system throughout a menstrual cycle.

Other research has found that between 19% and 40% of women with asthma report experiencing more intense and frequent asthma attacks or attacks just before or during menstruation. Perimenstrual asthma, as it is known, has been linked to increases in hospital emergency department visits and hospitalizations for asthma, including intubations.

A few small studies have also shown that women with MS report that their symptoms get worse just before menstruation or during menstruation. And lupus patients have reported experiencing more pain and fatigue when they are close to menstruating.

The evolutionary function of the menstrual cycle is to give a woman an opportunity to become pregnant, said Dr. Kimberly Keefe Smith, a reproductive endocrinologist and gynecologist at Brigham and Women’s Hospital in Boston, USA. When fertilization occurs, some parts of the immune system are suppressed so that the body does not reject the fetus.

During the menstrual cycle, the ovaries release estrogen and progesterone, which affect different branches of the immune system in different ways depending on the part of the body.

Progesterone, in particular, can be immunosuppressive when it is present in the body at high levels, such as during pregnancy, said Keefe Smith. But estrogen and progesterone alone don’t explain a weakened immune system, she noted. For example, patients who receive additional doses of the hormones during certain medical treatments or when they are using birth control are not more likely to feel sick.

Without definitive data, scientists do not have a clear position on how women should view their chances of feeling sick based on their menstrual cycle.

“This issue has been very little studied,” Klein said. “Because more detailed studies haven’t been done, I can’t really tell you whether you’re more likely to catch a cold or get an infection.”

While more research is needed to get a better understanding of how the menstrual cycle affects your propensity to get sick, Kelin said that if you always feel sick at a certain point in your menstrual cycle, don’t ignore that fact.

You can take steps to protect your health in the days leading up to your period: eat a balanced diet, get enough sleep, and wash your hands for at least 20 seconds. “Each woman knows her own body best,” Klein said.

Translation by Clara Allain