Some childhood onset epilepsy syndromes remit during adolescence, but others such as juvenile myoclonic epilepsy may begin during adolescence. While epilepsy overall affects equal numbers of boys and girls, specific epilepsy syndromes such as childhood absence epilepsy and juvenile myoclonic epilepsy may be more common in girls. Epilepsy in adolescent females deserves special attention given possible hormonal effects on seizure frequency, as well as interactions between antiepileptic drugs on menstrual cycle and oral contraception.

1. Is there an association between menstrual cycle and seizures?

Epilepsy is defined by more than two unprovoked seizures and is unpredictable in nature. In some patients, seizures occur in periodic patterns. If seizures consistently happen around specific times of the monthly menstrual cycle, this is called catamenial epilepsy. Keeping a calendar of the seizures and the menstrual cycle is helpful if such pattern is suspected. It is unknown how often catamenial epilepsy truly occurs in women, but most women with well controlled epilepsy do not have breakthrough seizures related to their menstrual cycle. About a third of women with difficult to control epilepsy have a consistent relationship between increased seizure frequency and monthly menstrual cycle. In these selected young women, breakthrough seizures may occur due the cyclical change in the sex hormones. Estrogen and progesterone, the female sex hormones, do not cause seizures but can influence seizure frequency. When seizures pattern is observed to be related to the monthly menstrual cycle, progesterone-containing oral contraceptives can be helpful in reducing seizures.

2. Which side-effects of antiepileptic drugs may be important to a teenage girl?

Concerns of adolescence such as weight, hair, skin, and face are normal for teenage girls. All antiepileptic drugs have side effects which are particular to the medicine, but some medications have known unwanted effects. The majority of antiepileptic drugs may cause some degree of tiredness. Dilantin (phenytoin) can cause excess hair growth. Depakote (valproic acid) is known to potentially increase appetite and thus may lead to unwanted weight gain. Depakote may also cause polycystic ovary syndrome which can result in irregular menses, obesity, and excessive hair growth due to raised testosterone levels and multiple ovarian cysts. If a teenage girl is taking oral contraceptive pills, specific antiepileptic drugs can reduce the effectiveness of contraceptive pills, such as carbamazepine, oxcarbazepine, phenobarbital, felbamate, topiramate, lamotrigine and primidone. Oral contraceptive pills containing estrogen will reduce the blood level of lamotrigine. The choice of antiepileptic drug or oral contraceptive pills can be adjusted to maximize seizure control and to prevent risk of unwanted pregnancy. Sexually active teenagers taking oral contraceptives need to be educated on barrier methods of contraception. Not only is there reduced effectiveness of oral contraceptive medications with certain antiepileptic drugs, oral contraceptives do not prevent sexually transmitted diseases.

3. Do the antiepileptic drugs cause long-term or permanent effects on reproductive abilities among young women with epilepsy?

The interaction between antiepileptic drugs and sex hormones continues only as long as the medications are taken. There is no known long term or permanent effects on reproductive abilities in women who have taken antiepileptic drugs in the distant past. In teenage girls who continue antiepileptic drugs into adulthood, however, issues of decreased fertility and choice of anticonvulsant during pregnancy will need to be discussed with the neurologist and the obstetrician. In pregnant women, valproic acid and carbamazepine carry the highest risk for fetal abnormalities compared to other antiepileptic drugs. Folate supplementation is recommended in young women of childbearing age, whether or not thinking about pregnancy, to reduced likelihood of fetal malformation. Certain antiepileptic drugs such as carbamazepine, valproic acid, and phenytoin can affect the balance between bone formation and breakdown.

To maintain bone health, the recommended daily allowance of calcium and vitamin D is advised. Women with epilepsy may require additional medical attention during menopause because of increased risk of osteoporosis.

Adolescence is an important time to address these issues because decisions for medication choice may be life long, and if so, will impact issues specific to women of childbearing potential, such as fertility and pregnancy. Educating teenage girls with epilepsy about these issues will empower them with growing independence and encourage them to seek guidance from their doctors on questions which they may be reluctant to discuss with parents. Assuming an active role in their medical care may also assist in the transition to adult healthcare services.

Lily Wong, M.D.
Last Reviewed: 1/15/11