I am on birth control and was taking batrim can i get pregnant? when ihad a period on june 26th/ i am on my third week of my pills and i had intercourse on the 9th

Some : Some antibiotics affect the effectiveness of birth control pills. Bactrim (sulfamethoxazole and trimethoprim) has been identified as one of the antibiotics that do interfere with the effectiveness of birth control pills. It is recommended that you use a back up method when having unprotected sex to prevent pregnancy while you are taking bactrim, (sulfamethoxazole and trimethoprim) and for atlease one week after you complete the regimen. If you had intercourse on june 9 and a period on june 26, then you were not pregnant at that time. Use a back up method anytime you take antibiotics and for one week afterward.

Most antibiotics OK : Some antibiotics, like rifampin, definitely interact with birth control.Others may in some individuals and with some pills .It probably depends on how your body metabolizes the drugs, and it may also depend on the dose of hormones in the pills.Most small studies don't show differences in the level of hormones in the blood, but to be on the absolutely safe side, use condoms during antibiotic use.