It certainly can change when you O after a m/c. My cycles were really not regular before my PG time. It varied between 19-36 days. I had my first AF 5w1d after my loss and then a 27 DC. I really do not temp or do OPKs either. I hope we both can tackle the figure out the O day and get a big BFP (if that is desired) soon. I also wish this for all other ladies that are TTC right now.