How a period is lost: Amenorrhea and its (various) causes

Recently, Tina Muir was featured as the first athlete in our “9 Miles With”series. She is an elite runner based out of Kentucky, has represented Great Britain in the World Championships, and is open about running and training on Instagram and her website. She keeps it real, to say the least. It’s fitting that her new website and podcast are titled “Running for Real.”

The catch: She’s not running right now.

She emailed me with her life update the same day we published the feature. She was apologetic. She hinted at the additional announcement coming soon. I said she has our support, 100 percent. In her public update, she shared with the world that part of her decision to stop running is to figure out why she’s not getting a regular period — or, in her words, has not had one in nine years.

She’s not alone.

A piece in Women’s Running addressed Tina’s announcement and the way it may resonate with so many active women. These things are kept secret for two main reasons: the shame women feel in talking about our periods, and the stigma surrounding eating disorders. Both “taboo subjects,” indeed. The author, Caitlyn Pilkington, shares her own experiences with running high school track, missing periods, and thinking, “It’s just what happens when you run a lot.”


an abnormal absence of menstruation, three or more missed menstrual periods or girls who have not menstruated by the age of 15. (To be clear, one type of amenorrhea can be caused by pregnancy, lactation, or menopause.) It is, by definition, not normal. It doesn’t happen just because you’re “active.” Physicians should know this, but many don’t. Or, at the very least, they don’t inquire further.

Amenorrhea is, by definition, not normal. It doesn’t happen just because you’re “active.”

Tina’s fear was that people would hear “didn’t have a period” and assume she had an eating disorder. Why? Because low body weight, low body fat percentage, and low energy availability are possible causes. In her Lane 9 feature, she was clear about not having disordered eating. She said that wasn’t something she has experienced. We honor that.

Photo provided by Tina Muir.
An eating disorder isn’t the sole cause of amenorrhea.

Tallying up calories in or out won’t explain everything. Tracking fat, carbohydrates, and protein intake won’t always solve the problem. Correcting “energy availability” will not always conjure up a menstrual cycle. Sometimes energy availability and body fat percentage are part of the equation. It’s important to address that; it’s OK to talk about it. But sometimes amenorrhea is caused by something other than an eating disorder.

The NIH outlines the additional possible causes of amenorrhea, including some types of birth control methods, thyroid problems, or a pituitary tumor. Anti-depressants, blood pressure medications, and gynecological conditions may also affect the menstrual cycle.

Hypothalamic amenorrhea may be the most common type of amenorrhea among active women.

It is the result of any of the following: low body weight, low percentage of body fat, very low caloric intake, emotional stress, strenuous exercise, leptin deficiency (a hormone that regulates appetite), or “some medical conditions or illnesses.”

Two out of the four of us have had amenorrhea.
Eating disorders look different on everyone.

An eating disorder may present as low body weight or low body fat percentage, but not always. Emotional stress may be the side effect of an eating disorder, or a number of other things (job stress, exercise stress, family stress, personal strife, etc.). Strenuous exercise is part of the job description for elite-level athletes. Leptin deficiency isn’t easy to recognize. We can’t see it in the mirror. We can’t review a food log and conclude we are “leptin deficient” after tallying up the day’s eats.

How do you “lose” a period?

There isn’t one answer to that question. All our stories are unique. Be cautious with assumptions about yourself or others. Part of the impetus to start the Lane 9 Project is a chorus of “Me too” that rang as Samantha, Alexis, and I told our stories. We all had amenorrhea. We all had doctors (coaches, and other health professionals) that ignored the issue. Said it wasn’t a problem. Chalked it up to “running,” and prescribed birth control pills, or nothing at all.

Health and psychological professionals need to address these issues.

First, they need to be AWARE of them. We, as women, need to be aware of them too. We need to know that being active doesn’t always result in amenorrhea. Amenorrhea doesn’t always indicate an eating disorder. But either way, it is not normal to not have a period, no matter what athletic level you’re on.

It’s okay to seek help. It’s okay to speak up. It’s important to know you’re not alone, and that it may be reversible. We’re here with you.

Are you an active lady or lady health activist, coach, mentor, parent, or healthcare provider? Join our community and newsletter.

If you want to share your story, get in touch with us through the form or by emailing

If you want to follow along, stay tuned here and say hi 👋 on Twitter or Instagram.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s