There is no medical or health reasons not to. I get migraines and cramps and find if I can get some sex asap, the pain is relieved some.
We always have sex when I have my period. I'm not going to miss out on literally months
of sex (all together) a year just because of a little uterine shedding. My Man isn't bothered by it at all.
We just put down either a maroon sheet doubled over or a Liberator Throe and a maroon towel over it and go for it.