This is what can happen to your period when you’re traveling abroad

Aside from a few minor inconveniences like jetlag and long customs lines, international travel is one of life’s best experiences. But, nothing’s perfect (not even that trip to your favorite European city) — and if you’ve noticed changes in your menstrual cycle during international excursions, it’s not a fluke — there’s a scientific explanation for the changes to your period when you’re traveling abroad.

According to research scientist Anna Druet, crossing time zones influences the regularity of our periods because international travel disrupts our sleep schedule.

But, what does that have to do with our periods? As it turns out, our menstrual cycles and sleep cycles are linked — so when our sleep is disrupted, our period follows suit.

"When we travel across time zones, we suddenly become exposed to light at different times of the day. This above all throws off our circadian rhythms," Druet explained to Broadly. "Research has shown that even a small amount of dim, artificial light triggers hormonal changes in the body."

According to Health, those of us who cross time zones frequently are most likely to experience menstrual changes when we travel, but all women should be prepared for period disruptions. And, of course, we never know quite what to expect — our period may arrive early, late, or we may skip it altogether. It may be lighter or heavier than usual, and the cycle could be shorter than our normal one (yay!) — or last longer (not cool).

So, when we pack our bags to embark on an international adventure, it’s a good idea to pack an extra box of tampons — and then we can hope and pray that we fall into the group of women who simply skip their periods when crossing time zones.