Yes its about Probiotics and whether it has side effects with the menstrual cycle? My menstrual cycle has always been like clock work. It comes every 25 days and last 4 days with first two days heavy bleeding and 3rd starts to taper off and my body starts cleaning itself out by day 4. I recently started taking Gnc Ultra 30 billion probiotic and after 8 days I had no problems. However my cycle should of started yesterday and instead I have very light if any blood at all to the point only a pantiliner needed? Not the norm and only change was Probiotics? So has it hurt my menstrual cycle? Is it not safe to take probiotics daily and what happens if you stop does all the good bacteria leave?