I remember that in my childhood, I was confused when I realised we were not allowed to touch women during their menstrual periods. I could not get any real explanation for this custom. Also they were not allowed to enter kitchen or rooms were gods are offered prayers.. I noticed this mostly in the ancestral home of my parents, when a large number of family members converge for some occasions and not (as far as I can remember) in my own home. Of course they were not allowed to enter temples during that time and this restriction continue even now. I was sure there were many more restrictions and taboos on menstruating women then and some are persisting.