Abstracts

RATIONALE: The effect of hormonal contraceptives on seizure frequency in women with epilepsy is ill-understood. There have been anecdotal reports off worsening of seizures in isolated cases, but the accepted belief is that estrogen-containing contraceptives do not affect seizures. However, there is little data to support or refute this belief. In animals and in some human studies, estrogens have been shown to exacerbate seizures. The purpose of this study was to evaluate the effect of estrogen-containing oral contraceptives (OC) on seizures in women with epilepsy.
METHODS: 142 consecutively evaluated women with epilepsy aged 14-55 years underwent reproductive endocrine interviews. Women with severe cognitive impairment were excluded. 21% women had primary generalized epilepsy (PGE) and 79% had localization-related epilepsy (LRE).Questions included exposure to oral contraceptives, type and duration of OC treatment and seizure frequency, severity and any changes in antiepileptic drugs during OC exposure. Women older than 55 years were excluded in order to maximize the accuracy of recall of reproductive history. Epilepsy evaluation included EEG and, when normal, sleep deprived EEG or LTEEG with minisphenoidal electrodes, and MRI. ILAE seizure classification was used. Patients with possible non-epileptic seizures were excluded. 67% of the women were interviewed on more than one occasion. Women whose answers concerning seizure frequency and severity during OC exposure varied at different interviews were arbitrarily classified as not affected by OC.
RESULTS: 44% of patients never used oral contraception. Among past and present OC users, duration of usage ranged from 2 months to 14 years. 22% of past OC users did not recall the brand or type of OC used. 21% of estrogen OC users (12% of all women) experienced worsening of seizures during usage of estrogen-containing OC. 62% of estrogen OC users experienced no change in seizure frequency or severity during OC use. 17% of estrogen OC users were unsure whether or not seizure freqeucy and/or severity changed during OC use. In two patients, seizures began shortly after initiation of contraceptive use. There was no difference in the effect of estrogen-containing OC on seizures among women with LRE and PGE.
CONCLUSIONS: Estrogen-containing oral contraceptives exacerbate seizures in possibly up to 20% of women with epilepsy who use them. This should be considered when councelling women with epilepsy on contraception. A prospective controlled study is needed to corroborate the results of this reptrospective study.