If you get less done at work or school during your period, you're in the majority: in a survey of nearly 33,000 women, 8 in 10 said the same. The cycle itself doesn't reliably change attention or memory. What gets in the way is pain, poor sleep and tiredness, and there's a lot you can do about those.
Is it true you think less clearly before your period?
It can feel that way, but tests don't back it up. In 2025, researchers pooled 102 studies with almost 4,000 participants: attention, memory, language and reasoning didn't change in any reliable way across the cycle.
The brain fog is real, though. It just has other causes. Pain and a sleepless night eat into anyone's focus, and for some people PMS adds mood swings and clumsy days when you drop everything.
So you don't need a timetable that puts hard tasks in one phase and routine in another. If your notes show that day one of your period knocks you out, keep the hardest task off it when you can.
How do I prepare if my exam falls on my period?
Pack a kit the night before: extra pads or tampons, spare underwear, water and a snack. Arrive a little early, find the toilets and ask whether you can step out during the exam. Once that's sorted, it's easier to stay calm.
If your periods are painful, don't wait for the pain to peak. Doctors suggest starting anti-inflammatory painkillers like ibuprofen 1–2 days before a predictable period, taken as the pack says and ideally after food. Ibuprofen isn't for everyone: with asthma, a stomach ulcer or pregnancy, check with a doctor or pharmacist first.
Before you leave in the morning, a hot water bottle wrapped in a towel on your tummy or a warm shower can help. If you use tampons and it's a long day, change them every 4–8 hours and never leave one in for longer than 8.
Common questions
Should I tell my boss or teacher?
Only if you want to. Otherwise, "I'm not feeling well today and need a break" or a request to reschedule is enough. In the same survey, only 1 in 5 women who called in sick because of their period gave the real reason, so you're far from alone with your cover stories.
My period is late during exams. Is that the stress?
It might be, because serious stress can delay a period. If you could be pregnant, take a test first, and if delays keep happening, see a doctor.
How do I plan if my cycle is irregular?
Keep a kit in your bag every day, even when you're not expecting your period. And log how your days go in HeySis: even without a clear rhythm, you'll see what gets in your way most.
In short
- Pack a kit the night before: pads, underwear, water, a snack
- Find the toilets before the exam starts
- Pain getting in the way of work or study? See a doctor: it can be treated
Source: PLOS ONE: Menstrual cycle effects on cognitive performance (meta-analysis)
Educational content; it does not replace professional medical advice.