Is birth control effective the first day you take it after your period ends?

I take birth control regularly every month.. while on my period I know the pills in the pack are inactive pills used as everyday reminders.. when my period ends and I transition back from the inactive pills to the active ones am I protected from pregnacy with that first active pill.. say if I had sex the day after my period ended?Is birth control effective the first day you take it after your period ends?
Yes, if you take the pills regularly and don't miss they are 99.99% effective. The active pills contain hormones which prevent you from shedding the uteran wall (menstruation), when you go on the innactive pills you lack the hormone and therefore start your period. You won't ovulate duiring this time and so you won't get pregnant. As a reminder in order to make sure that you are protecting yourself properly it is recommended that you take the pill at the same time daily.
Defiantly. If you have been on birth control for more than one month it will be enough to sort your cycle out. You do not ovulate again even with out the pill until around 10 days later regardless so you will be fine.