"To our knowledge, this is the first case in which migraine attacks were triggered by orgasm," lead author Dr. G. D'Andrea and colleagues at the University of Parma report in the August issue of the journal Cephalalgia.

Migraine headaches are characterized by intense pain, sensitivity to light and sometimes nausea and vomiting. Migraines can be preceded by auras, which are typically flashes of light or blank spots in the field of vision.

"Two to five minutes after every orgasm, (the woman) suddenly began to experience blurred vision in the left or right side of the visual field, developing into a flickering zigzag line together with pinpoint circles of red and blue light," the authors explain.

According to the researchers, three types of sexual headache are recognized by the International Headache Society. In the case of the woman in the present report, the researchers believe her migraine could potentially fit into type 2--"a sudden severe headache occurring at orgasm."

However, they point out, there are several differences between their patient's symptoms and those typically experienced by type 2 migraine sufferers. Namely, type 2 sexual headaches are more commonly seen in men and the pain is more often on both sides of the head.

Regardless, D'Andrea's team reports that the woman responded positively to treatment with 100 milligrams per day of the drug lamotrigine, which is sold under the name Lamictal.

In the first 6 months of treatment, the doctors stopped the treatment twice and the woman's migraine attacks "promptly recurred." After 2 years of continued treatment, the woman again went off the drug and has remained migraine-free after orgasm for the past 33 months, the report indicates.

While the researchers can offer no specific explanation for the cause of the woman's orgasm-induced migraines, they note that her case highlights the effectiveness of lamotrigine in the prevention of migraine with aura.