How long before Depo stops periods altogether?

My special-needs daughter had her first Depo shot in December. She'd only had two episodes of break-through bleeding prior to the shot. She just had her first period since the shot. Her pediatric team has indicated that Depo Provera is the best route for her and her sister because it typically stops the period from happening after a few months.

Has anyone had their period stop altogether? How long did it take to do so? It's actually the desired effect for my girls since they don't understand any of it.

[Dr. Kokil Mathur]

Hi!
Yes, it is true that depot shots can cause amenorrhea or absence of periods. This can happen after the first depot shot cycle or after a few cycles or even after 2-3 years. Women continue to get irregular bleeds and spotting meanwhile. Only 50-70 percent of women are free of periods after about 2 years of use. Hence there are a considerable few who will get periods after this also. It is very important to discuss this with your daughter's gynecologist and see what best can be done for her. Take care!

[Nymariarya]

Thanks for the response!  

Is there a better option to cease her cycle?  She doesn't have a gyn yet as there is no way she'd endure an exam with her delays. We started the shot as soon as possible after her first breakthrough in the hopes that she'd cease before she got regular.