Catamenial epilepsy: when seizures follow your menstrual cycle

For some people who menstruate, seizures are not spread evenly across the month. Instead, they cluster around certain points in the menstrual cycle, and the pattern repeats cycle after cycle. This has a name — catamenial epilepsy — and the way to find out whether it applies to you is refreshingly practical: record your seizures and your cycle dates together, and let the pattern show itself.

What catamenial epilepsy is

Catamenial epilepsy means seizure activity that changes with the menstrual cycle. The word “catamenial” comes from a Greek term meaning “monthly.” It is not a separate disease or a separate type of epilepsy. It is a timing pattern that can appear alongside many forms of epilepsy: during certain phases of the cycle, seizures become clearly more frequent, and this happens month after month, not just once.

This is a recognised concept in epilepsy care, described in the medical literature for a long time. So if you have a feeling that your seizures follow your cycle, you are not imagining it — the link is real for some people, and it is worth investigating properly.

Why the cycle can affect seizures

The menstrual cycle is driven by hormones, the body’s chemical messengers, whose levels rise and fall in a regular rhythm across the month. These same hormones also act on the brain. Shifts in the hormonal balance can change how easily brain cells fire — some shifts nudge the brain toward being more excitable, while others have a steadying effect.

For most people this makes no noticeable difference. But in some people with epilepsy, the seizure threshold — how easily a seizure can start — seems to move with these hormonal tides. That is why hormone changes appear on lists of recognised seizure triggers, alongside better-known ones such as missed sleep, stress, and missed medication doses. Our article on common seizure triggers covers the wider list.

When in the cycle seizures may cluster

Doctors describe the pattern in terms of general windows rather than exact days, because every cycle is a little different:

• Around menstruation. Seizures cluster in the days just before or during the period.
• Around ovulation. Seizures cluster near the middle of the cycle, when an egg is released.

Not everyone fits one of these windows neatly, and some people notice a window of their own. The defining feature is repetition: seizures gathering in the same phase of the cycle, cycle after cycle.

Why tracking is the key to diagnosis

There is no single blood test or scan that confirms catamenial epilepsy. The diagnosis rests on demonstrating the pattern — and that takes two records kept side by side: every seizure with its date, and your cycle dates, starting with the first day of each period.

One month is not enough, because a single overlap can be coincidence. Doctors typically ask for seizures and cycle dates recorded together across at least two to three cycles before a pattern can be confirmed. Several cycles showing the same timing turn a hunch into evidence a neurologist can act on.

This is exactly the job a seizure diary was built for. If you are not keeping one yet, our guide to keeping a seizure diary explains what to record and how to make the habit stick.

How to track both together

The method is simple, and consistency matters more than detail:

• Log every seizure with its date and time, plus a short note on what it looked like.
• Mark the first day of each period. If you can, note when it ends as well.
• If you already track ovulation, add those dates too. If not, don’t worry — period dates alone are a strong start.
• Keep notes on other likely triggers, such as short sleep or missed doses, so a hormonal pattern is not confused with something else.
• Keep going for at least two to three full cycles before drawing conclusions.

A seizure diary app makes this easier: entries take seconds, nothing gets lost, and a calendar view lets you and your doctor spot clusters at a glance. If you prefer paper, our printable seizure diary templates work just as well — simply mark your cycle days in the notes column.

What happens next

Bring your record to your appointment. Your doctor may first want to rule out other explanations, and may ask about your cycle, your medication routine, and your sleep. If the record supports a catamenial pattern, your neurologist may discuss options with you. What that involves is individual — it depends on your seizure type, your cycle, your overall treatment, and your own priorities. The important part is that the conversation is grounded in real data instead of guesswork.

Never change or stop your medication on your own while you wait for that conversation. An unsupervised change can make things worse.

When to talk to your doctor

Raise the question at your next appointment if you suspect any link between your seizures and your cycle — even before you have months of data, so your doctor knows what to look for. Get in touch sooner if your seizures are becoming more frequent or longer, if a new seizure type appears, or if seizures disrupt your daily life around your period. And remember the standard rule: a seizure lasting more than 5 minutes is a medical emergency — call emergency services right away.