My Friend Ask Me A Question I Don't Know How

my friend ask me a question i don't know how to answer her so here it is she wants to know if she had some one pre cum evin if its a little can she still get pregnant even though she just got her period she said it was 3 - 5 day before her period started when that happened and if so how can she stop it with out going to the doctor's she ttanks its been about a week know