An understanding of what the mucus plug is may help you understand what is happening to your body as you prepare to go into labour.

What Is the Mucus Plug?

While you’re pregnant, the opening of your cervix is blocked by thick mucus. 1 This protective mucus accumulates inside your cervical canal during the pregnancy and acts as a barrier or plug, keeping unwanted bacteria and other sources of infection from traveling to your uterus and reaching your growing baby.2

When Do I Pass the Mucus Plug?

Generally, you’ll pass your mucus plug when your cervix begins to efface (soften and thin) and dilate (open) as it prepares to deliver a baby.1 However, passing the mucus plug does not necessarily mean that you’re about to go into labor. While most women don’t lose it until after they’ve passed 37 weeks of pregnancy, in some cases you can pass the mucus plug days or even weeks before your due date.1 There are other reasons that you may lose your mucus plug:

  • When you see your doctor for a prenatal visit, they may check your cervix. This may stretch or irritate your cervix, causing the plug to fall out.1
  • In general, it’s not considered harmful to have sex while you’re pregnant, Sexual intercourse towards the end of your pregnancy can loosen the mucus plug.1

If you’ve lost your mucus plug sooner than week 37 of pregnancy, please contact your healthcare provider.2

What Does a Mucus Plug Look Like?

What a mucus plug looks like will vary from person to person. However, there are a few characteristics that may be present:1

  • Stringy, sticky, or jelly-like in texture.
  • Clear, off-white, or tinged red, pink, or brown in colour.
  • Generally odourless.
  • 1 to 2 inches (~2.5 - 5 cm) long.
  • 1 to 2 tablespoons in volume.

You may lose your mucus plug all at once or gradually over time and never notice that it’s happened, especially since there is often increased discharge during pregnancy.1 However, the structure of a mucus plug is generally thicker and more jelly-like than regular discharge; there’s also typically more of it at once.1 You may see it on toilet paper after using the bathroom or in your underwear, or not at all.1

Another type of pre-labor discharge is the bloody show. This may frequently be mistaken for a mucus plug, and vice versa; while they may occur simultaneously, they are not the same. The mucus plug, is the collection of mucus that acts as a barrier to your cervix. The mucous plug falls out when the cervix starts to dilate, efface or both.1 The bloody show may happen at the same time, as it is the result of blood vessels rupturing in your cervix as it expands and readies for labour.1

Should I Call My Doctor If the Mucus Plug Falls Out?

Every pregnant person will lose their mucus plug at some point. It’s a normal part of pre-labor and should not be accompanied by pain or side effects. However, there are a few instances where you should contact your doctor or healthcare provider:1

  • If you lose your mucus plug before you reach 37 weeks of pregnancy.
  • If the loss of your mucus plug is accompanied by heavy bleeding, pain, and contractions.
  • If you feel a sudden rush of fluid from your vagina, immediately after losing your mucus plug.

Additionally, you can call your doctor if you’re not sure if what you’ve passed is actually your mucus plug. Note the size, colour, and consistency to help your doctor determine what it is.

The mucus plug is a normal part of pregnancy. It helps to protect you and your baby from harmful bacteria and infections and can signal the beginning of labour. Understanding what is happening to your body can help to ease your mind as you prepare to have your baby.