EMBARGOED FOR RELEASE:
Dec. 2, 2017
WASHINGTON, D.C. – Many women with epilepsy first develop seizures during puberty,
implicating high levels of certain hormones produced during that time of life, suggests an
analysis of a large national epilepsy registry being presented at the American Epilepsy Society 71st Annual Meeting.
While researchers are aware that seizures often begin with the onset of menstruation, the
new study shows the connection is even more powerful when looking beyond the first
menstrual period to the eight-year span of puberty. Analyzing more than 1,100 women in the
registry, researchers determined 49 percent had their first seizure between two years before
and six years after their first menstrual periods.
“The levels of some hormones in the blood increase 10-fold during this time of life, including
neuroactive steroids that affect the brain and make a seizure more likely,” said Andrew G.
Herzog, M.D., MSc, senior author of the study and director of the Harvard Neuroendocrine
Unit of Beth Israel Deaconess Medical Center, Boston. “Clearly more seizures develop in girls
during that period of time, so we need to begin looking at risk factors as well as potential
For the study, researchers reviewed data from the Epilepsy Birth Control Registry of 1,144
women with epilepsy (ages 18 to 47 years) who had provided reproductive information. They
determined that 8 percent of the women first experienced seizures the year they had their
first menstrual periods, which is four times greater than would be expected by chance.
(Among the women in the registry population, the chance of seizure onset during any given
year between birth and age 47 would be slightly more than 2 percent.) However, the 8
percent number is relatively small, meaning it is not a strong predictor of seizure onset. The
researchers wondered if they could better predict seizures by looking at a span of years, and
found 49 percent of the women had experienced their first seizure during the range of two
years before and six years after the beginning of menstruation, which is two-and-a-half times
greater than would be expected by chance.
During puberty, the body begins producing massive levels of hormones, which prompt sexual
maturation. Some of these hormones are neuroactive, meaning they can “excite” brain cells,
which increases the risk of a seizure, particularly those with other risk factors. In the first
two years after menstruation begins, girls ovulate (produce eggs) in only about half of the
menstrual cycles. In cycles in which they don’t ovulate, they produce estradiol (estrogen),
which increases the risk of convulsions from a seizure, but not progesterone, which decreases
the risk. Previous research by Dr. Herzog found women with epilepsy are 30 percent more
likely to have convulsive seizures during menstrual cycles in which they don’t ovulate.
The incidence of seizures increases in boys during late childhood and adolescence as well,
likely also implicating hormones, Dr. Herzog said.
The next step is to assess girls who may be at risk for developing seizures, such as those who
had seizures related to a fever or suffered a head injury. Those at risk could be more closely
watched and potentially treated with medications such as steroids that can inhibit
neuroactivity that leads to seizures, Dr. Herzog said.
“We need to look at the whole puberty process and this massive increase in hormone
production,” said Dr. Herzog. “If we have a better idea of how hormones are acting on the
brain, we can develop appropriate treatment.”