Onset of epilepsy at the time of menarche.

The authors compared the frequency of epilepsy onset in perimenarche with epilepsy onset in other childhood periods in 94 postmenarchial patients aged <55 years. Seizure onset was higher for the 12 to 15 year age bracket than for other ages and clustered around menarche. Epilepsy began during the year of menarche in 17% of patients vs 5.5% expected (p < 0.001), and during +/-2 years of menarche in 38% patients vs 22% expected (p < 0.001). Seizures worsened during perimenarche in 29% of girls with pre-existing epilepsy. Perimenarche may be a risk for the development and worsening of epilepsy.