I had regular periods on implanon until the last 5 or so months. My implanon has been expired since February. I started my period 5/28 and didnt start again until July 15. then i started early in August, the 7th. And now I'm still waiting for my next period..... My concern is that implanon can cause your period to be irregular or completely absent but mine was fine and now it's expired and I'm having odd periods. What do you think is going on?