Hormone shifts? Certainly changing estrogens levels can cause headaches, and
women vary in their sensitivity to this. I started having migraines only
after my 1st child was born, and have big fluctuations in HA frequeny that
are clearly related to what's going on in the estrogen department (what's
left of it...) - starting or stopping my estrogen replacement, changing any
med or herbal supplement that has an effect on est. production or
utilization, etc.

Cathy Bargar, RN, IBCLC