The mucus plug is a thick mucus, secreted by the cervix, to protect the womb and baby during pregnancy. The mucus plug carries antibodies that are able to neutralize bacteria, viruses, and other disease-causing agents. It acts as a barrier at the opening of the cervix and it stays there until your cervix starts to make changes, like dilating and/or softening. This usually happens in late pregnancy but can happen sooner than that. The mucus plug looks different for every person but it can vary fr