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You have taken the pills 6 hours apart, which you should have done 12 hours apart. Anyway, not to worry there could be 75-90% protection. You may wait if your periods are delayed more than 10 days, to get a Urine pregnancy
test done to confirm. The brown discharge is one of the side effects of taking the pills. Your periods may also get postponed and may result in heavy bleeding. See your Gynaecologist if the periods are very much delayed and/or if your pregnancy test is positive as there are medical methods of medical termination of pregnancy if you wish not to have the early pregnancy. GOOD LUCK !!!!