I have some birth control patches that says they expire

Patient: I have some birth control patches that says they expire May 2015 and some that say they expire June 2015. Should I even bother with the May ones or should I use the June ones? Will they be effective

Doctor: Thank you for writing to us.I recommend that you not use the May birth patches. I think that you should only use the June ones. And in future use patches which expire after 6 months.I hope this helps you. All the best.