Has anyone taken provera to regulate cycles while TtC?

Did you take it before your expected period date (on an average monthly cycle) to start it but turned out pregnant? Does it affect or harm the egg after implantation? Can it cause a miscarriage?

I called my obgyn office but the nurse told me she was unsure and to wait it out but that would make my cycles 41 days long. And not every month and that’s NOT what I want.

If I’m not pregnant I wanna get my period after cd31 but I’m scared to take my provera because I’m afraid if I fall pregnant, that it would cause me to miscarry. I want all 12 chances this year but I’m nervous to take it on time. Help!