For women, it is a sign of ovulation right before you menstruate (get your period). it is also the bodys' natural lubricant for sex, to make it more enjoyable. It is also your body's natural way of cleaning your vagina out.
It is possible but highly unlikely. When you have your period it is to flush out your system, it it not? When you get pregant right before your period (Before the sperm reaches the egg) the period flushes it out.
You can get pregnant at any time of the month. But right after your period you have a less chance of getting pregnant, and right before your period because the egg needs to be in the tubes to be fertilized so if its the day before your period its not in the tubes.