It’s often only after a drug is released do we learn women might be affected totally differently from men — as with the case for two recent major studies.

Specifically, the new research points to the role of estrogen, which naturally ebbs and flows over the course of a menstrual cycle.

Changing levels of estrogen has major impacts across the entire body under normal circumstances. Introduce medication into the mix, and it becomes a whole different ballgame.

“For too long, the menstrual cycle has been treated as background noise in health research,” said Poppy Cooper, an author of one of the recent studies. “This work is part of a growing shift in that thinking and a recognition that the menstrual cycle has impacts beyond reproductive health.”