I just started my period, I consulted all my books they all mostly talk about fertility and conception. One of them says to be concerned about milk supply if you start your period in the first six months but that is all it says.
My DS is 6 months old - I have a more than ample milk supply, in fact I had to work to get it down! My son feeds quite often and I don't see any problems with my supply up to now. I just assumed I would not be having my period because of this.
I just want to be prepared if I need to take steps to make sure I keep my supply up.
Mine drops just before my period and during O. It makes my son fussy and me very irritable. My son eats solids now but when he didin't I had to nurse more often. Eating oatmeal can help and even oatmeal cookies...there's mother's milk tea, too.
I'm afraid I am not much help. I just got my first cycle and my son is almost 10 months. But at this point, I haven't noticed a decrease in supply.