July 28, 2016
font size

Definition of Mucus plug

Mucus plug: An accumulation of mucus and thick fluid that blocks the opening of the cervix (the opening from the uterus to the vagina) during pregnancy. The mucus plug serves to protect the uterus and the fetus by preventing bacteria from entering the uterus. The mucus plus can be clear or slightly pink in color and can be tinged with brown or red blood. As the cervix slowly begins to dilate prior to the onset of labor, the mucus plug is expelled. When expelled, the mucus plug has been referred to as "bloody show." When the mucus plug is expelled, it may be noticed by the woman as a solid mass or as increased vaginal discharge over a few days. Sometimes the woman may not notice passage of the mucus plug since it can occur gradually. Also spelled mucous plug.

Source: MedTerms™ Medical Dictionary
Last Editorial Review: 5/13/2016

Drug Medical Dictionary of Terms by Letter

Top RxList Drug News

Parenting and Pregnancy

Get tips for baby and you.

Use Pill Finder Find it Now See Interactions

Pill Identifier on RxList

  • quick, easy,
    pill identification

Find a Local Pharmacy

  • including 24 hour, pharmacies

Interaction Checker

  • Check potential drug interactions
Search the Medical Dictionary for Health Definitions & Medical Abbreviations