Who said that?

"Abnormal central nervous system response to normal fluctuations in hormones is the likely cause of menstrual migraine. Patients with menstrual migraine do not generally have hormonal abnormalities."

Elizabeth Loder MD
Menstrual Migraine - Opinion Statement
Current Treatment Options in Neurology, 2001, Vol 3 (2)

Where is this abnormal CNS response? In the brainstem, where the upper cervical nerves mix with the trigeminal nerves.

The ability of the upper cervical spine to contribute significantly to the underlying abnormal CNS activity has been majorly underestimated, largely because traditional manual techniques have been ineffective for treating headache and migraine.

Now using techniques developed specifically for headache