Most women have some change in their periods, including bleeding more days than usual, spotting between periods, or no periods. This is most common during the first year.
Lots of people who use the shot stop getting their period altogether after about a year of using it. This, like all the side effects of the shot, goes away after you stop getting the shot. Your period should go back to normal within a few months after your last shot wears off.
If you decide that you want to get pregnant right away after you stop getting the shot, you should know the shot may delay your ability to get pregnant by up to 10 months. However, some people do get pregnant soon after stopping the shot. There’s no way to know how long it will take for you.