Can Travel or Night Shifts Change Your Period?What Studies Found

Plenty of women swear a long flight or a time change moved their period. Here is what the studies actually covered.

Ordinary trips

We looked for research on whether a vacation or a single trip across time zones shifts a period, and we didn’t find any. So if your period comes early or late after a trip, the research can’t say the trip caused it, and it can’t rule it out.

Night shifts

The best evidence comes from the Nurses’ Health Study II, which looked at 71,077 nurses aged 28 to 45 who weren’t on the pill.¹

Nurses who had worked rotating night shifts for 20 months or more in the previous two years were about 23% more likely to report irregular cycles.¹ Those nurses were also more likely to have cycles 40 days or longer, and the more months of night shifts, the stronger the link.¹ The authors called it a modest association.¹ It was a single snapshot from 1993, so it can’t prove the shifts caused the change.¹

Flight attendants

Flight attendants report more cycle problems than other workers.² A US study compared 694 flight attendants with 120 teachers:²

• Flight attendants had more frequent cramps.
• The physical side of the job, especially lifting heavy loads, was linked to irregular cycles and worse cramps.

So for people who fly for a living, the physical work may be part of why their cycles change.²

Packing for a period

1. Track it. Note trips on your period record. Over a few cycles you’ll see whether travel lines up with anything for you. See why your period is late or irregular.
2. Count hours, not time zones. Change a tampon every 4 to 8 hours and never wear one longer than 8.³ A long flight with a connection can pass that easily.
3. Wait for the period. Use tampons only when you have your period.³ A liner can cover you until it arrives.
4. Pack extra products, a change of underwear in your carry-on, and pain relief.
5. Book the aisle on long flights.

If you can go 8 hours on one tampon, the absorbency may be too high.³ For nights, see how to stop period leaks at night, and for tampon safety, see toxic shock syndrome.

Try: “Since I started rotating night shifts my periods have become unpredictable. Here’s my cycle record and my shift schedule. Is this worth looking into?”

Period, Handled covers this in Chapter 10, “Work, Travel, Gym, Bed,” in a section called “On the Road.” Its Pack It plan uses your Period Scorecard to find the shortest stretch you went between changes on your heaviest day, so a flight or a drive gets planned around your own numbers. See the book.