(Ines Vuckovic/ Dose)

There’s a grain of truth to the myth.

Our Middle School Mysteries series investigates childhood rumors you never bothered to fact-check yourself.

When I was a little girl, my Aunt Laurie made me terrified of one day becoming a woman. She insisted that once I hit puberty, eating chocolate would make for a face full of pimples. She told me never to use a douche unless I wanted “a loose vagina.”

I know now that someone who regularly goes on “ghost hunts” is not the most reliable source of scientific information. But at the time, I was young and impressionable. So when Aunt Laurie told me that it was impossible for a woman to have their period in water, I believed it. “Not in a shower, a bath or a pool!” she claimed.

In fact, I spread that old wives tale around dozens of slumber parties until I watched the horror movie “Carrie,” which changed everything.

“Carrie,” which is based on a Stephen King novel, tells the story of a shy teenage girl who uses supernatural powers to enact revenge on the snotty high schoolers who bully her daily. The film includes a scene that no pre-pubescent girl will ever forget. It takes place in the showers of Carrie’s high school locker room. Sixteen-year-old Carrie is scrubbing herself clean when she begins to menstruate for the first time. The poor girl’s Bible-thumping mother had sheltered her so completely that Carrie doesn’t know what’s happening to her body, and she starts to panic. Some bitchy girls nearby watched her hysterics and began ridiculing her. “Plug it up! Plug it up!” they chant. Trust me—it’s traumatic. But my 12-year-old brain, the scene served another purpose, for I had seen a woman bleed in water.

This scene created a disconnect in my young brain that followed me into adulthood. I’m 27 years old now and have been menstruating for over 14 years. To my knowledge, I’ve never bled in water—and I’ve been keeping watch! Nevertheless, I’ve had girlfriends tell me I’m crazy and boyfriends tell me they still won’t fuck me in the shower. So you can see I was confused.

That’s where the internet came in. I recently decided to Google this myth to see who was right: my girlfriends or Aunt Laurie. I immediately found an article on the website of Seventeen Magazine debunking the fallacy that your period simply stops when you get in water. The writer had interviewed Dr. Deborah Nucatola, who is the senior director of medical services at Planned Parenthood. You have to know a ton about vaginas to get that job, so I figured she was qualified to weigh in on this issue.

Nucatola told Seventeen that periods don’t cease when you get in water — but they may appear to. Here’s why: “Your period doesn’t slow down or stop in water — it just may not flow outside the vagina because of the counter pressure of the water,” Nucatola said. In other words, the outer layer of your uterus will continue to shed whether you’re in a hot tub or the ocean or a fjord in Norway. But if you’re submerged in water, the pressure of it may keep your flow from actually exiting your vagina.

There’s another element at play, too: gravity. You’re often horizontal when you’re in pools, lakes, tubs, etc. So you’re challenging the gravitational forces that usually help to bring forth your crimson tide. As pointed out by the Menstrual Cycle Calculator, a website designed to help women better understand their menses, even if you’re standing vertically in a pool, gravity will have diminished ability to pull out your flow. Basically, gravity’s effect is reduced when you’re in water, no matter your position.

That said, I wouldn’t advise going sans ‘pon in a white bikini — just in case. No woman’s period is exactly the same, so you shouldn’t count on the water acting as a blood-plug.

There you have it, Aunt Laurie. Periods don’t just stop in water — but the crimson wave may not flow from your vagina as freely, if at all. That’s why our protagonist Carrie’s ruby run flowed so freely that her stuck-up peers could see it from 10 feet away: She was neither submerged nor horizontal in that locker room shower. In conclusion, I’ll award one point to Team Carrie, and one for kooky old Aunt Laurie, because her well-intentioned advice did have a grain of truth.