provera questions

So i have PCOS and was prescribed provera for three cycles along with metformin to take twice daily. I completed the first cycle of provera and got my period from March 21st-25th. I tested positive with ovulation strips 3/31-4/1 and had sex during the fertility window. My doctor told me to start the second cycle of provera 3-4 weeks after beginning the first cycle. My question is what if I happen to be pregnant now? (Doubtful but you never know!!) I don't want to take the provera because I read there could be birth defects if taken within the first trimester? Do you think I should take a pregnancy test around the time I should be starting the next cycle of provera and if it comes out negative to just continue taking the medication as directed? And obviously if it comes out positive to not take the next cycle of provera? Of course these are the things I should have asked my doctor but obviously didn't think of this until now! I'd love to hear what you ladies think! This is our first month TTC so it's all new to us. Thank you again for the feedback.