"Those wily women with eyes 'false in rolling', who change their moods and affections like chameleons." Sonnet 20, William Shakespeare

400 years ago when the brilliant Shakespeare first penned this keen observation, commenting on the ever-changing nature of a woman's spirit, the knowledge that a woman's emotions could fluctuate with her hormones was unknown. The first hormone would not be discovered for another 300 years, and shortly after - the components of the menstrual cycle would be elucidated. Given the rapid advancement of science in the twenty first century and the ease with which peering into the brain has become; one would think the influence of the sex hormones estrogen and progesterone on cortical and subcortical regions implicated in a woman's emotional and cognitive processes would be fully understood. Not so.

In a recent review in the Journal of Psychoneuroendocrinology, brave authors gathered all that science could currently tell us regarding the function of hormones in the female brain. While investigations included women undergoing experimental manipulations such as hormonal treatments for gender dysphoria, I will only focus on naturally cycling women (NCW) and those on oral contraceptives (COC).

High hormonal status was defined for estrogen (E2) as late follicular or COC use, while for progesterone (P4) late luteal for NCW or COC use. Low hormonal status was defined as early follicular for E2, follicular for P4 or non-COC use.