 [ Symptoms ] when can i have unprotected sex with my new husband after taking antibiotics  after being on birthcontrol for years i recently went on sulfamethtrimethoprim 800 i took 2 pills twice a day for 7 days the day i started my antibiotics was the same day i started my placebo pills which i started my period four days later as usual on the last day of my antibiotics i started my new pack of birth control as prescribed gildess fe 1 530 i am curious when my husband and i can have unprotected sex with no concerns of getting pregnant help we are newlyweds [ Disease ] if i am not mistaken the mayo clinic studied this and said only one anti biotic has been shown to impact birth control is effectiveness at all it is rifampin out of an abundance of caution some doctors suggest using a second form of birth control for a month i am not sure how much it is affecting your life now or how much an unwanted pregnancy would mess things up i never bothered with an extra form of birth control bc of anti biotics but surely one month of a back up will not hurt