The Mucus Plug and Its Role in Labor

Mucus Plug
Photo © Dorling Kindersley/Getty Images

There are few things that cause as much contemplation and yet avoidance in discussing labor than the mucus plug. This is very simply, the plug of mucus that fills the cervix to protect against disease and infection during pregnancy. It actually does not completely block the passage to the inside of the uterus, but it does inhibit the passage of bacteria. In fact, it has been theorized that the mucus plug actually has many immunologic properties, meaning it helps to prevent infection, and that when it is not working properly, you may be at a higher risk of preterm labor.

Currently these studies are small but continuing to grow.

As the end of your pregnancy comes closer, the cervix begins to prepare for labor by softening and dilating. This may cause the mucus plug to start leaking out as the cervix slowly starts opening before labor. If this happens, you may notice an increase in discharge that doesn't really smell, or the mucus plug may come out in one big chunk. Either way it can be pink or tinged with blood, this is normal and why you may hear people refer to bloody show.

If you lose your mucus plug, you may wonder what that means in terms of when labor will start. The truth is we don't know. It is certainly a good sign that your body is doing everything it should prior to labor and is progressing in that direction - towards labor. However, you may not notice it, so not seeing it does not mean that your body isn't making this progression.

If you do lose the mucus plug, this is not an indication that labor is imminent.

Certainly labor could start on its own at any point and the closer you are to the 40 weeks mark of pregnancy, the more likely that is to happen. Some people have lost their mucus plug and promptly had their baby, but others have also lost their mucus plug and waited weeks for labor to begin. This is not a sign that something is wrong.

Once you have lost your mucus plug, you do not need to make any special accommodations. There is no ban on having sex or taking baths simply because you have lost your plug. If you have specific questions, call your doctor or midwife, even between appointments. You do not need to save your mucus plug to show anyone, feel free to flush it down the toilet.

Be sure to talk to your doctor or midwife at your prenatal care appointments about the signs you're experiencing at the end of pregnancy as you progress towards labor. They can help guide you into the most appropriate behaviors and actions, not to mention answer your questions.

Also Known As: Bloody Show or losing your plug

Alternate Spellings: mucous plug

Examples: I started losing my mucus plug about a week before my baby was born.

See a photo of a mucus plug.

Sources:

Becher N, Adams Waldorf K, Hein M, Uldbjerg N. Acta Obstet Gynecol Scand. 2009;88(5):502-13. doi: 10.1080/00016340902852898. The cervical mucus plug: structured review of the literature.

Hansen LK, Becher N, Bastholm S, Glavind J, Ramsing M, Kim CJ, Romero R, Jensen JS, Uldbjerg N. Acta Obstet Gynecol Scand. 2014 Jan;93(1):102-8. doi: 10.1111/aogs.12296. Epub 2013 Nov 25. The cervical mucus plug inhibits, but does not block, the passage of ascending bacteria from the vagina during pregnancy.

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