How long until birth control pills work?

my girlfriend is about to start on her birth control pills for the first time, we be wanting to have sex ( next to condom of course) but we have contracted not to until she gets on birth control to be sheltered and not just rely on a piece of rubber. So my grill is how long does it takes for the pills to work. Thank you.
Answers:

Mentrual? Uh ?

I'm a moment ago going back on them, so, newly talked to my doctor around all this.
If she starts the pill on the first year of her period it is supposed to be significant right away.
If she starts the first Sunday after her period it is supposed to be successful after seven days.
My doctor recommends Sunday start because it is easier to remember when to run them. (Good idea for a first timer.)
She also recommend with a Sunday start that you continue one full month to be completely sure it has taken effect.
It should be important after seven days but every women is different.
You do not have to linger three months.

Pain itchy vagina? yeast infection?

seven days

Will i lose the weight presently i'm off my depo?

She requests to wait at most minuscule 3 months of consistant taking before have sex without condoms. I can't stress the consistant cog enough..she can't skip any pills, or she runs the risk of getting pregnant.