Are you referring to when he ejaculates onto your vagina?
Or...
If he ejaculates when he pulls out?
Because in the first case, from what I know once sperm has hit the air it has become dead, and I figure it would be very unlikely to become pregnant from dead sperm,lol.
And the second case is yes, you can get pregnant even if he pulls out "pre cum" can still get you pregnant, and that is what I have gotten myself into and won't know the results untl 4 more weeks.
In n e case, just be careful hun!