Yes. Pre-ejaculation fluid may contain sperm, which means that a woman can get pregnant even when ejaculation doesn't occur within the vagina.
Withdrawal of the penis from the vagina before ejaculation is one of the oldest methods of birth control. It's free, readily available and has no side effects. Still, withdrawal is unreliable at best — and it offers no protection from sexually transmitted infections.
If you're trying to prevent pregnancy, choose a more reliable type of birth control. If you're not sure which type of birth control is best for you, ask your doctor to help you understand the options.