I know one of the reasons women don't get included in the medical research. It's precisely because of that lovely wave form of hormones. The drugs being tested will not behave reliably depending on where a woman is in her cycle. So, instead of recognizing this, and creating prescription rules to adjust accordingly, the people doing the testing "simplify" the number of variables by only including postmenopausal women in the study. Their goal is to show their drug has a statistically better result than the standard options. Statistics are easier with fewer variables.