Female hormones like oestrogen and FSH have daily ebbs and flows that may explain mood variations and why some female shift-workers struggle to get pregnant
Source:
https://www.newscientist.com/article/2215596-women-have-a-daily-hormone-cycle-as-well-as-a-monthly-one/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home