Thank you for your query at DoctorSpring.com.
I understand your concern but you do not have to worry. There is no chance of her getting pregnant. This is because she was in her periods. There will be no egg to get fertilised even if your sperms reached her womb. Hence no conception and no chance of pregnancy.
There is no need for her to go for emergency contraception like Plan B pill or anything else.
I hope that addresses your concern.
Feel free to ask queries.