My girlfriend and I had sex on May 10, 2015

Patient: My girlfriend and I had sex on May 10, 2015. I wore a condom and finished inside, but when I pulled out, the condom stayed inside of her. Some sperm leaked out and got on her. I’m concerned the condom could have slipped off sooner and I didn’t notice. On May 10 she was on day 7 after getting her period. She has a longer cycle…30 days, and ovulates (according to her ovulation app/calendar) around 16 days after she gets her period. She took a Plan B pill within 40 minutes. I guess our concern is what is the likelihood of pregnancy if she still has 9 days or so before she ovulates, and I read that sperm can live up to 5 days. Given that she took the Plan B pill right away, should we be concerned?

Doctor: