Percentage chance of getting pregnant from pulling out during ovulation?

20-30%.: The same for unprotected intercourse. At young age that could be a 1/3 to 1/5 chance of pregnancy per cycle with unprotected vaginal intercourse. Your girlfriend should be taking Folic Acid 1-5 mg daily and check home pregnancy tests 1-7 days after a late period. Good luck!

Fair: No statistical analysis, however if you put sperm in vicinity when it is known an egg is in play, it makes inadvertent fertilization much more likely. Contraception cannot work in absence of common sense. Best to wait 2 weeks and check pregnancy test. Good luck!