Many people notice menstrual cycle changes after receiving an MS diagnosis. This could be due to stress over MS symptoms, which can intensify during menstrual periods. MS medications can also cause irregular menstruation.

Multiple sclerosis (MS) is an autoimmune disease that affects your central nervous system, which includes your brain and spinal cord.

Most people with MS receive their diagnosis between the ages of 20 and 40 — often the peak reproductive years.

While the condition weakens the immune system, it can also affect the reproductive system, including your overall menstrual cycle and menstruation.

If you feel like your periods changed after your MS diagnosis, you could be right.

In a 2018 study involving 181 participants with MS and 202 control subjects, researchers found that those with the condition experienced more symptoms before, during, and after menstruation.

Irregular menstruation increased from 21% to 40% after the initial onset of MS, compared to about 25% among the control subjects.

Roughly 39% of people with MS noticed changes in overall menstruation.

You may see an increase in premenstrual syndrome (PMS) symptoms, including:

  • mood shifts
  • irritability
  • fatigue (low energy)
  • difficulty concentrating
  • decreased libido

PMS symptoms typically appear a few days before your period and disappear a few days after you get it.

Although more research is necessary to understand the relationship between MS and your menstrual cycle, hormonal fluctuations may be a contributing factor.

Sex hormones — including estrogen and progesterone — regulate your menstrual cycle, and some research suggests they may also influence MS activity.

The relationship between MS and your menstrual cycle goes both ways. Research finds you’re more likely to have a relapse of motor symptoms, vision problems, and trouble with coordination in the 3 days before your period.

Doctors call these temporary bouts of symptoms pseudo-exacerbations. Sometimes, it’s hard to know whether symptoms like weakness, pain, and fatigue are from MS or your period because they can feel very similar.

Your mental sharpness and motor skills can also experience changes right around the time your period is due. In a 2019 study, people with MS did worse on tests of mental and physical performance just before their period.

One reason for the change is that your body temperature rises slightly during your period. Even a tiny increase in temperature can make MS symptoms worse.

Some medications used to manage MS can increase the risk of irregular menstruation.

This includes beta interferons, which are a disease-modifying therapy for relapsing forms of MS, and selective serotonin reuptake inhibitors, which are a type of antidepressant.

You might notice light bleeding or spotting between periods and periods that start earlier or later than usual. These side effects may ease over time.

If you experience unwanted changes in menstruation or other unusual side effects after taking MS medications, you may want to share your concerns with your doctor.

They may be able to recommend an alternative medication or offer other strategies that can help.

Birth control pills and other forms of hormonal contraception may help regulate your menstrual cycle. Some people experience a decrease in overall menstrual bleeding, while others find that menstruation stops altogether.

Medications that manage MS may also help with certain aspects of PMS. For example, drugs that help regulate the immune system may ease the mental fog some people experience right before their periods.

You can also try a nonsteroidal anti-inflammatory drug like aspirin or ibuprofen (Advil, Motrin). These over-the-counter pain relievers may help with menstrual cramps, breast or chest tenderness, and other body aches.

Research has found connections between menstrual changes and MS. The disease and medication used to treat it share a link with irregular menstrual cycles and increased symptoms.

Irregular menstrual cycles may become more predictable after you start treatment for MS, but that doesn’t mean you’re stuck with these symptoms until then.

You might consider reaching out to a primary care physician or OB-GYN to discuss your options for hormonal birth control, whether you’re starting it for the first time or switching to a different method.

Your neurologist can also review your current MS treatment plan and discuss new therapies or other modifications that better target your current symptoms.