I am on microgestin de 15/30 and I take nitrofurantoin

Patient: I am on microgestin de 1.5/30 and I take nitrofurantoin as a preventative for UTIs. I only take the nitrofurantoin after sex, and I have only taken one within the last seven days. Yesterday I had sex with my boyfriend and he ejaculated inside me, and now I am nervous about my risk of pregnancy. Should I take plan B to be safe?

Doctor: Hi,Thanks for the query.I understand your concern.According to studies available, there may not be any major difference in contraceptive efficacy of birth control pills because of intake of a single dose of nitrofurantoin.So, if you are using the pills as per the schedule without missing, you may not need an emergency contraceptive pill.If you want to continue nitrofurantoin, better to use an additional contraceptive measure like condoms till the completion of dose.Take care