I've been on birth control for two years and have always taken it right. However this past month I began taking my pills for the first week or so and had intercourse with my boyfriend without a condom since im on the pill (He always withdrawls just as an extra precaution). However, a day later I found out that I had a Urinary tract infection and was put on an antibitoic for it. I started taking the antibitotics the day after we had sex so im worried that maybe the medicine will make my birth control less effective and i could become pregnant. All the doctor said was to use extra protection during and after the pills but nothing about if you had sex before starting them. And my pharmacist actually told me that only a few antibiotics are known to even affect birth control but im still very confused. And the antibiotic im on is one that is not known to affect the pill. Anyone have any insight on this matter?