Medically reviewed by Peter Weiss, MD A mucus plug is a thick clump of mucus that forms a seal at your cervix (the opening to your uterus) during pregnancy. It protects the fetus from bacteria and ...

Others only notice a trickle of water or a feeling of wetness in their underwear. The mucus plug is a thick collection of mucus that seals the opening of the cervix. This stops bacteria from ...