the black, red, white symbolism derives from the menstrual and reproductive cycle of women… black is representative of the sloughed lining of the uterus… Red symbolizes both the retention of blood… White is the mother’s milk
Estés argues that alchemical colour symbolism derives from observed stages of the menstrual-reproductive cycle, proposing that alchemy is a later symbolic effort to replicate the transformative vessel of the uterus.
, Women Who Run With the Wolves Myths and Stories of the Wild, 2017thesis