It is possible to conceive from the pre-ejectulation fluid. Partners should take caution as contact of the pre-seminal fluid with the vagina can result in a pregnancy. It is rare but it can take place.
It is allways better to practice safe sex, the use of a condom is reccommended.
pre-ejaculate has little to no sperm
It is normal. It is called pre-ejaculation fluid. Because you are conscious of it, that is why you lose the erection. That fluid has more sperm in it than your ejaculation (***) so take precaution if you want sex with girlfriend.