Periods (the menstrual cycle)

• About the menstrual cycle
• Polycystic ovary syndrome
• Seizures and your menstrual cycle
• Premenstrual tension

About the menstrual cycle

Your menstrual cycle starts on the first day of your period and ends on the day before your next period starts. Most women have a menstrual cycle of between 24 and 35 days. The average is 28 days. If you have epilepsy, you might find that your periods happen more often than every 24 days or less often than every 35 days.

Many women have regular periods, so the number of days between the start of one period and the start of the next is the same each time. Some women have irregular periods. The number of days between the start of each period can be different each time. Some women have periods very rarely. If you have irregular periods, it can make it harder for you to get pregnant.

Any woman can have irregular periods. However, they seem to be slightly more common in women with epilepsy, especially women who have frequent seizures. Irregular periods may be caused by epilepsy itself, seizure patterns or anti-epileptic drugs.

If you have irregular periods, it would be a good idea to talk to your family doctor. They will look into all the possible reasons for this and try to find ways to help you have regular periods.

Polycystic ovary syndrome

In a small number of women, irregular periods are caused by a medical condition called polycystic ovary syndrome (PCOS). Women with PCOS have lots of tiny cysts on their ovaries and unusual hormone levels. This makes it difficult for them to get pregnant. Other possible symptoms of PCOS include weight gain, acne and excess body and facial hair.

If you have temporal lobe epilepsy, or take the anti-epileptic drug (AED) sodium valproate, there is slightly more chance that you will develop PCOS than other women. There is even more chance if you have taken sodium valproate from a young age. However, if sodium valproate is the cause of the PCOS, the PCOS goes away when you stop taking sodium valproate.

It is worth talking to your family doctor if you notice any of the following:

• Your periods are often less than 21days apart
• Your periods are often more than 35 days apart
• Your periods last longer than seven days

Your doctor can look into the possible causes, which include PCOS. They can then suggest treatments that may help you to have more regular periods.
If you do have PCOS, your doctor may advise you to change your AEDs. Or they may suggest you take the combined oral contraceptive pill, which may help to prevent PCOS.   

It is very important that you do not stop taking your AEDs without getting advice from your doctor. This could cause you to have more seizures.

Seizures and your menstrual cycle

You may notice that you have more seizures than usual at certain times of your menstrual cycle. This could be at the start of your period, around the middle of your menstrual cycle, or in the week before your period. These seizures could be caused by the changing levels of hormones in your body. When there is a link between your menstrual cycle and your tendency to have seizures, it is called catamenial epilepsy.

If you think you may have catamenial epilepsy, it would be a good idea to keep a seizure diary for three months. This would help you and your doctor to see if there is a pattern. If there is, your doctor can discuss possible treatments with you. One possible treatment is the drug clobazam (Frisium). This can be taken as well as your usual anti-epileptic drugs, but just on the days when you are at a higher risk of having seizures.

Premenstrual tension

It’s not unusual for any woman to feel moody, bloated, stressed and anxious in the days leading up to their period. This is known as premenstrual tension (PMT). Some people with epilepsy find that feeling stressed or anxious makes them more likely to have seizures. If this applies to you and your PMT causes you to feel stressed or anxious, you might notice that you have more seizures when you have PMT.