Chances of getting pregnant with precum. Precum is a fluid whose secretion is the outcome of involuntary body function. As such, the emission process is impossible to control. Unlike other effective forms of birth control, such as pills or condoms. Precum secretion happens right before ejaculation. The withdrawal (or pull-out method) is not a useful measure as prevention against pregnancy. Even if the penis is pulled out right before the climax, precum is still found to enter and exit into the partner's vagina. The pre-cm or pre-ejaculatory fluid is secreted by twin structures called 'Cowper's glands. These glands are at the base of the penis.