Pregnancy Risk with Pre-ejaculate: What You Need to Know

Question
Hi,

I've been doing some research and want to know the likelihood of getting pregnant from precum.  It's my understanding that precum itself contains no sperm, however if a man has ejaculated within the previous few hours before intercourse then sperm could be contained in the precum and still be viable.  What in fact are the chances that a pregnancy could occur in this scenario?

Thanks!

Answer
I think your understanding is generally thought to be true, although I don't think anyone can say that precum never contains sperm.  It's thought that if a man has ejaculated recently, sperm will be present (reduced or eliminated if he urinates).  However, withdrawal is generally not a very effective method of birth control.  If withdrawal is always done correctly, about 4 women out of 100 get pregnant in 1 year.  That suggests that either they're doing it wrong, or there are sperm in precum.  For the usual use of withdrawal as birth control, about 25+ women out of 100 get pregnant in a year.