Throughout your pregnancy, a thick collection of mucus has been sealing your cervix, creating a barrier between your baby and the outside world. This is your mucus plug — and it has been quietly protecting your baby from bacteria and infection since early pregnancy.
As your body prepares for labor, your cervix begins to soften, thin out (efface), and gradually open (dilate). When this happens, the mucus plug is dislodged and comes out. This is a normal and expected part of late pregnancy, and it means your body is doing exactly what it is supposed to do.
Losing your mucus plug is one of the early signs of labor, but it is one of the less reliable predictors of timing. Unlike regular contractions or your water breaking, the mucus plug can come out days or weeks before active labor begins. Understanding what it looks like and what it does (and does not) mean can help you avoid unnecessary anxiety.