Pregnancy possibility from non-penetrative sex?

Patient: Dear Doctor(s), me and my girlfriend were doing non-penetrative sex in the form of genital rubbing, and both of us are still wearing our underwear,however during this I ejaculated inside my underwear (briefs) while the fabric is still in contact with the fabric of her underwear..I’m wondering whether or not it is possible for her to get pregnant from this (i.e. what’s the chances of conception happening from this)?Thank you for your attention.

Doctor: