Well for the most part with cycling women, their hormones are gonna be at different place in the cycle. (justinhealth.com)
Due to the menstrual cycle women can see some pretty crazy fluctuations in weight. (physiqonomics.com)
The authors also speculate that the use of oral contraceptives may influence a woman's ability to attract a mate by reducing attractiveness to men, thereby disrupting her ability to compete with normally cycling women for access to mate. (livescience.com)