What Pregnant People Should Know About the Mucus Plug

The mucus plug is a clear, thick, jelly-like mucus. In early pregnancy, the mucus plug forms, sealing the cervix (which sits between the vaginal canal and the uterus) with thick mucus to keep bacteria from entering the uterus.

The mucus plug protects the fetus from infection and helps prevent premature labor. Without it, maintaining a pregnancy to term would be unlikely and, in some cases, impossible.

Read on to learn about the importance of the mucus plug and what to expect after you lose it.

Why the Mucus Plug Is Important

The mucus plug is formed in early pregnancy from secretions of cervical glands and has a thick, gelatinous consistency. Within this thick, sticky fluid are antibodies that can protect the growing fetus from many bacteria, viruses, and other disease-causing agents.

The mucus plug is affected by pregnancy hormones, primarily progesterone (which thickens the mucus in early pregnancy) and estrogen (which thins the mucus in late pregnancy).

Shortly before labor begins, the mucus plug thins as the cervix gradually softens, thins, and opens. The passing plug indicates that labor is nearing, regardless of the pregnancy stage, which is why you should contact a health care provider right away if you believe you've passed the mucus plug before reaching term. Passing the mucus plug can be a sign of impending preterm birth.

What the Mucus Plug Looks Like

While mucus plug is usually odorless like everyday vaginal discharge, the appearance and texture can vary. The mucus plug may appear in any of the following colors and textures:

• Creamy to yellowish-white
• Streaked with pink
• Pink
• Brown
• Red-tinged
• Beige or brown
• Thick and jelly-like
• Stringy or sticky

Mucus Plug vs. "Bloody Show"

When the mucus plug comes out, capillaries in the cervix may also rupture. This rupture sometimes results in passing visible streaks of blood along with some mucus, which is why some people refer to the loss of the mucus plug as the "bloody show."

Though the events are related (and often occur at the same time), they are different. A "bloody show" is the result of bleeding from the cervix as it dilates, whereas losing the mucus plug is discharge from the gelatinous glob that dislodges as the cervix begins to open. Not everyone passes a mucus plug with blood.

When Does the Mucus Plug Pass?

It is impossible to predict precisely when the mucus plug will pass, as it varies from person to person and pregnancy to pregnancy. The mucus plug could pass sometime before labor, generally after 37 weeks, or after other labor symptoms have begun.

If you are at term (past 37 weeks) and lose your mucus plug and don't immediately don't go into labor, don't worry. Even if you don't go into labor for a few weeks, the amniotic fluid in the gestational sac offers ample protection for your fetus right up until the time your water breaks.

In some cases, you will notice the mucus plug in your underwear, in the toilet, in the shower, or on a piece of toilet paper when you wipe after using the bathroom. In others, it comes out gradually over a few days, and you may not notice it at all.

How Long After Losing the Mucus Plug Does Labor Start?

If you happen to be aware of when your mucus plug comes out, or you notice a bloody show, remember that losing your mucus plug doesn't tell you anything about how soon labor will start. It could mean that labor is just a few hours away or you still have weeks to go. 

The best way to know whether labor is about to begin is to watch for other signs of labor, including:

• Contractions that are regular and get closer together
• Lightening (when the fetus drops and settles into your pelvis)
• Your water breaks

When To Contact a Health Care Provider

Sometimes people suspect that they've lost their mucus plug when in fact, they're noticing vaginal discharge unrelated to the mucus plug. Many people experience increased vaginal discharge during pregnancy.

Other times, pregnancy discharge can indicate infection. If you notice the following, contact a health care provider:

• Any vaginal discharge that is not usual for you
• Vaginal irritation or pain
• Uterine contractions
• Fluid leaking from the vagina

Note the appearance, texture, and amount of discharge so you can describe it to your health care provider. They can then tell you what other signs to watch for and whether you should take further precautions.

Additionally, if passing the mucus plug is accompanied by heavy bleeding or a deep red discharge, contact a health care provider immediately, as these signs can signify potential complications.