By Pat Anson, Editor

Changes in female hormones may trigger migraines in adolescent girls, but the frequency and severity of headaches depends on a girl's age and stage of puberty, according to a new study.

Researchers at the University of Cincinnati's College of Medicine and Cincinnati Children's Hospital Medical Center evaluated 34 girls between the ages of 8 and 17 who suffered from migraine.

They found that higher levels of the hormone progesterone were associated with fewer headaches in older teenagers, while lower levels of the hormone resulted in more headaches. In younger girls, the opposite appears to be true.

The findings are published online in Cephalalgia, the journal of the International Headache Society.

"Ours is the first study to show that migraine headaches might also be influenced by female hormones in girls with migraine," says Vincent Martin, MD, a professor and co-director of the Headache and Facial Pain Center at the University of Cincinnati’s Gardner Neuroscience Institute.

"While low and declining estrogen levels are thought to precipitate migraine in adult women, we found that progesterone (appeared) to be the most important trigger factor in these young girls. However, this effect seemed to differ depending on the age of the girls and their pubertal development."

Migraine affects about three times as many women as men. In addition to headache pain and nausea, migraine can cause vomiting, blurriness or visual disturbances, and sensitivity to light and sound.  

About 10 percent of school age children in the U.S. suffer from migraine, according to the Migraine Research Foundation (MRF). As adolescence approaches, the incidence of migraine increases rapidly in girls and by age 17 about 23 percent of girls have experienced migraine.

About two thirds of adult women will develop "menstrual migraine" -- migraine attacks that occur shortly before or during menstrual bleeding. Low and declining levels of estrogen are thought to trigger menstrual migraines. Prior to this new study the contribution of female hormones to migraine was unknown in girls and at what age they begin.

"There is a dramatic change in the way that female hormones affect migraine that occurs during puberty," said Martin. "Prior to puberty, progesterone has little effect on migraine, but after puberty high progesterone levels are associated with fewer headaches and low progesterone levels have more headache."

Girls aged 16 to 17 in the study had a 42 percent chance of having a headache when their progesterone levels were low, but when levels of the hormone were high the chance of headache dropped to 24 percent.

In the 8 to 11 age group, there was 15 percent chance of suffering from migraine or headache when levels of progesterone were low, but a 20 percent chance when high levels of progesterone

"Our study suggests that female hormones play an important role in triggering headaches in young girls and that their response to hormones seems to change at the time of puberty," says Martin. "Since migraine commonly begins during puberty in girls one might ask whether a change in response to hormones might represent the initiating factor for migraine in some girls -- kind of like the ‘big bang’ theory of migraine."