Cervical mucus plug usually refers to a jelly-like liquid formed locally during late pregnancy due to the secretion of mucus from the cervix, commonly known as cervical mucus plug. The cervical mucus plug serves to lubricate the birth canal. The flow of cervical mucus plug does not necessarily mean that the birth is imminent, but is mostly related to the contractions and the condition of the pregnant woman. When the contractions become more frequent and stronger, labor may be possible in a short time, so the main signs of labor are considered to be regular contractions, fetal head descent and redness. The cervical mucus plug may be one of the main manifestations of contractions, but it does not necessarily lead to labor immediately.