My sister got the Depo-provera shot on March 7th.
She never had sex before so she could get the shot without timing for her period.
She said she usually gets her period somewhere between to 20th or 25the of the month,
She was told the shot would take at least two weeks to start protecting agaist pregnancy,
She waited a month before she had sex.
She had her period in March, But not April.
She's worried she may be pregnant. I've heard thatsome women on Depo-provera, may not get their period at all, but I'm not sure if it can vary like this. Could she be pregnant? Or is her period just regulating?

While pregnancy is a possibility, since no birth control is 100% effective, it is more likely her body responding to the injection. Some women will continue to have regular periods, many will find they become irregular, and some eventually cease altogether while receiving the injections.

Hello, I have been on depo for 2 years. I got the shot the first time like your sister, just whenever. They say roughly two weeks could be 1 could 3, but she wouldn't have gotten her period in the month of April because the shot is fully in place now, were as before it wasn't 100% working.
If she is still worried you can get a pregnancy test, and stop her worrying :)