Ah, then the website I read was wrong.
Thank you for clearing that up for me.
And I'm happy to know that my birth control is that effective.
Its very common to have irregular bleeding or spotting while on Depo. Or not to have any period at all.
If you do not have a period, the uterine lining is not shed.
However, Depo Provera does not thicken the uterine lining. It works by inhibiting the hormones that stimulate the ovaries to produce eggs. It can thicken the cervical mucus and making it harder for sperm to penetrate, too.
You do not need to use condoms while on Depo, unless you are doing so for STD protection, or just feel the need to be super, super careful. Depo is about 99% effective at preventing pregnancy by itself.