The mucus plug is made of thick mucus produced by glands in the cervix. Near the end of your pregnancy, when the cervix begins to soften, thin, and dilate, it may fall out. The mucus plug fills the cervix and prevents microorganisms from entering the uterus. Losing your mucus plug means your cervix is getting ready for labor, but it is not a sign that labor has begun or is imminent. Your cervix can start to dilate several weeks before delivery.
What to Expect
If you notice globs of mucus in your underwear or when you use the toilet, that may be a sign that the mucus plug is loosening or coming out. Do not be alarmed if it is slightly blood tinged; that is common and occurs because of small tears in the cervix that cause bleeding. You may lose the mucus plug over several days or even weeks as the cervix slowly prepares for labor. It is not uncommon to dilate several centimeters before labor begins. If this happens, you might lose your mucus plus gradually and not even notice it. Some women lose their mucus plug all at once during labor. If your mucus plug comes out during labor and is blood tinged, your doctor might refer to it as the "bloody show."
What to Do Next
Losing your mucus plug does not mean that labor has started. You do not need to rush to the hospital when it happens unless your water breaks or you have regular contractions. Even then, call your doctor first. If you bleed heavily when losing your mucus plug, as with a period, you should definitely call your doctor right away.