So I have an IUD but I still have crazy weird periods. Mine usually last between 12 to 15 days long. They're fairly regular, but I've only been tracking them with this app for four months. I started taking probiotics about two weeks ago to help with chronic yeast infections. I had just finished my period. My fiance and I had sex last week, and now my period is late by a few days according to this app. Do probiotics effect the menstrual cycle?