Amenorrhea (pronounced uh-men-o-REE-uh) is the medical term for the absence of menstruation (a period). It is not a disease itself, but rather a symptom of an underlying hormonal, physical, or lifestyle-related condition. 

Your body is secretly a drama queen, and it stops the period when it thinks there's a serious crisis.

• You're Training for a Marathon (or just running a lot): Your body sees all that intense effort and says, "Whoa, whoa, whoa. Clearly, we're being chased by a saber-toothed tiger. We are in survival mode! No time for reproductive niceties!"

• Stress: You've been burning the candle at both ends. Your brain (the control tower) decides, "This environment is too hostile for, well, anything. Abort mission! Shut down non-essential services!"

• The PCOS Plot Twist: The hormones are in a chaotic, rowdy party, and no one can hear the signal to start the cycle. It's too noisy in there!

• The Thyroid Switcheroo: This is the gland that controls your metabolism's speed. If it's too slow or too fast, it messes with the rhythm. It's like having a DJ who keeps changing the music tempo on the dance floor.

If your period has been missing for three episodes in a row, it's time to call in the medical detective. They'll help figure out if it's just stress or if your internal plumbing needs a quick tune-up.