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Signs of Labor: The Mucus Plug

Katlyn Joy | 3, February 2014


The final weeks of pregnancy one question weighs heavily on every expectant mom's mind; is it time? Wondering if labor is starting or when it will begin is a prevalent thought. Many women hear about the mucus plug, the bloody show and the start of labor.

What is the Mucus Plug?

Like a stopper in a bathtub drain, the mucus plug is the barrier between the vagina and the uterus at the opening of the cervix. The vagina contains microbes, while the uterus is sterile and the mucus plug is the barrier stationed between these two areas. It stays in place through pregnancy, until labor nears. The cervix ripens in the final weeks of pregnancy, meaning it will become thinner and more open or dilated.

As the cervix thins and dilates, the mucus plug may become disengaged and fall out from your vagina. It will appear as a pinkish or brown vaginal discharge. Sometimes you may see the rather intact mucus plug, which will often appear as a glob of thick or stringy mucus which may or may not be tinged with blood. If it streaked with blood, it is referred to as "bloody show." This is an excellent predictor that labor will begin soon. But don't head to the car just yet; labor may be mere hours away, or perhaps up to a couple weeks longer.

The Unique Role of the Mucus Plug

Research is new in this area, but so far studies have looked into the properties of the mucus plug. For instance, a study in 2002 which was published in the American Journal of Obstetrics and Gynecology found that the mucus plug is not only a physical barrier from bacteria entering the uterus from the vagina, but also a chemical barrier to keep the uterus free of infection.

A 2009 Scandinavian study looked further to discover evidence that the mucus plug serves as a gatekeeper in the woman's body, but should the plug become impaired in its function, it may result in preterm labor.

In 2013 more research on this idea was carried out and published and the authors found that by studying properties of the mucus plug, higher risk of preterm birth was associated with mucus plugs which were more permeable and therefore more likely to allow bacteria to pass through. The implications are that doctors some day may be able to screen patients for this risk and take steps to head off premature births.

How Can You Tell?

Should you be in week 37 to 40 especially and you notice a definite change in your vaginal discharge, particularly light bloody discharge which may be pink or brown, a gelatinous ball of gooey material or anything of that type, it's likely your mucus plug. You can take it as a sign that things are preparing for baby's arrival.

However, should the blood be bright red and be a soaking type of discharge that requires frequent pad changes or seems to be heavier than a couple teaspoons, you need to call your doctor. It could indicate something more serious such as a problem with the placenta. One way to determine if something could be awry? Does it seem more like a discharge or more like a period? If the latter, get it checked out as soon as possible to rule out more critical problems.

Other late stage pregnancy signs preceding labor include lightening or when baby drops into the position for birth, increased Braxton Hicks contractions or the beginning of light contractions, water breaking or the leaking of amniotic fluid, diarrhea, a spurt of energy often called the nesting instinct where you may feel a need to prepare your home for the baby, and finally contractions will begin in earnest.

Anytime any symptoms seem odd to you or you have a feeling that something isn't right, put in a call to your health care provider. There is nothing wrong with heeding your gut and finding out. It's always better to be proactive and rule out any real reason for worry.

Related Articles

Signs of Labor

Preterm Labor & How To Avoid Preterm Labor

Hypnobirthing, A New Way To Labor

Preterm Labor

The Three Stages of Labor


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