if efficacy is your goal -- preventing an unintentional pregnancy -- it would be wise to use a second form of birth control such as condoms until you complete one full packet of birth control pills have a normal period and then start the next packet. even then condoms will always be an effective second level of insurance.
will my beyaz birth control pills be effective if i take it 13 days after the start of my period? . i ended my period last week thursday and today is wednesday 10/3.