Your body is now prepared to safely undergo the physical trauma of birth. The increased blood volume and clotting abilities protect you from losing too much blood, and the increased blood flow allows both you and your baby to get the necessary amount of oxygen during contractions. The muscle cells in your uterus have increased in size and number, and every muscle fiber is enhanced so that muscle contractions can occur more consistently. You may lose the plug of mucus that has tightly sealed the inside of your uterus from the vagina. This mucous plug looks like a big glob of slime and is usually brownish in color.
Most women notice it on toilet paper or in their panties.
This does not necessarily mean you will begin labor immediately, it is just one of the stepping stones. About 15 percent of women will start the labor process with their water breaking. This is the amniotic sac leaking fluid. When this occurs you may notice either a large gush of fluid or a small trickle of fluid. Sometimes the only thing a woman notices is that her panties are wet.