What Is Mucus Plug In Pregnancy And How Does It Look Like?

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The mucus plug in pregnancy is a thick layer of mucus that forms in the cervical canal (1). The plug helps prevent the carriers of bacteria and other harmful microorganisms from entering the uterus and infecting the baby.

When the cervix starts to dilate during childbirth and pushes the baby out of the womb, the cervical mucus plug moves into the vagina and eventually exits the body.

Learn more about the mucus plug and what to expect after it comes out of your body through this post.

What Is The Mucus Plug?

A mucus plug is a collection of mucus that forms a thick layer in the cervical canal between the vagina and the uterus. The mucus, which is secreted by the uterus during pregnancy, accumulates and forms the mucus plug. It appears as a jelly-like substance, either white or slightly pink.

Research has shown that the mucus plug contains high levels of immunoglobulins and phagocytes, which act as a gatekeeper for the fetus (2).The mucus has the potential for adaptive immunity, protecting the fetus against various infectious microorganisms.

Does Losing The Mucus Plug Indicate Labor?

Losing the mucus plug in pregnancy may not always indicate labor. It may mostly indicate that your cervix has started to dilate in preparation for labor, which could happen anytime later in pregnancy, although it cannot be said when (3). It is always beneficial to look for other signs and symptoms of labor that often begin in the last few weeks of the third trimester.

  • Lightening: By the end of the third trimester, the baby starts to settle lower down towards the mother’s pelvis (4). This process is known as lightening or dropping. It may lead to a change in the shape of your belly and frequent urination due to pressure on the bladder.
  • Membrane rupturing: During pregnancy, a protective layer of fluid called the amniotic sac surrounds the developing fetus. Towards the end of the third trimester, the amniotic sac ruptures due to a hole or a tear in it (5). This process is known as the rupturing of membranes. It is also called ‘water breaking’ as the amniotic fluid gushes out of the body.
  • Cervical thinning (effacement): The thinning of the lower uterine segment and cervical canal to prepare for the baby’s birth is known as effacement. During this process, the cervix gradually becomes thinner, softer, and shorter (6).
  • Dilation: By the end of the third trimester, the cervix softens, becomes thinner and gradually dilates to facilitate the baby’s delivery. This process of expansion of the cervix is known as cervical dilation (7).
  • Strong regular contractions: Muscles of the uterus may contract and relax as your approach your due date (8). When you start to experience strong contractions at closer time intervals, it indicates that you have gone into labor. These contractions gradually increase in frequency and intensity and help push the baby out of the birth canal.

How To Know When You Have Lost The Mucus Plug?

During pregnancy, it can be difficult to differentiate between vaginal discharge and losing the mucus plug. However, you can figure out whether or not you have lost the mucus plug by either checking your underwear for signs of mucus or the tissue paper after going to the bathroom. The mucus plug is jelly-like in appearance and can either be clear or slightly pink in color.

Some women lose their mucus plug all at once, whereas, in others, it can come out in small fragments over a period of a few hours (9).

What To Do After Losing Your Mucus Plug?

Losing the mucus plug is not always an indicator of labor. The time of losing the mucus plug could help you decide the next step.

If you lose your mucus plug within less than 36 weeks of pregnancy, it is important to consult your doctor at the earliest and assess the condition. It might signify a complication in the pregnancy or indicate preterm labor (3).

Losing your mucus plug after 37 weeks of pregnancy is considered normal as it is a sign that the cervical canal is preparing for labor. However, you must see a doctor or visit emergency care if mucus plug discharge is accompanied by strong uterine contractions, fluid discharge from the vagina, or vaginal bleeding. These signs may indicate that you are getting into labor.

What Is Bloody Show?

Bloody show is the term that is used to describe the phenomenon of the release of a small amount of a mixture of blood and mucus from the vagina (10).  It is a very common phenomenon that occurs towards the end of the third trimester of pregnancy.

It should also be noted that bloody show and mucus plug are not the same things. A mucus plug is mostly transparent and contains very little or no amount of blood, while a bloody show is a mixture of blood and mucus.

How Long After Bloody Show Will You Go Into Labor?

A bloody show is a sign that you will go into labor soon. However, the exact timing of going into labor after a bloody show cannot be determined as it varies from one woman to another (10). It is important to inform your doctor about the same.

The mucus plug is a protective layer that prevents pathogens and other harmful substances from entering the uterus and affecting the developing fetus. Losing the mucus plug does not always indicate labor. Talking about the signs and symptoms of mucus plug discharge and labor with the healthcare provider is important as it can prevent any complications towards the completion of pregnancy.

Frequently Asked Questions

1. What comes first, dilation or mucus plug loss?

The cervix starts to dilate during labor, which in turn leads to the loss of the mucus plug.

2. How much discharge does a mucus plug amount to?

The total volume of the mucus plug amounts to around one to two tablespoons (3).

Key Pointers

  • A mucus plug is a pinkish jelly-like mucus layer between the vagina and the uterus.
  • It acts as a protector for the fetus by preventing the entry of various microorganisms.
  • If you notice the mucus plug in your underwear, inform your doctor as it may indicate a complication or labor based on the gestation period.
  • If you notice bloody mucus, check for the signs of labor mentioned in this post.


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Sanjana Bhattacharjee

Sanjana did her post graduation in Applied Microbiology from Vellore Institute of Technology, India. Her interest in science and health, combined with her passion to write made her convert from a scientist to a writer. She believes her role at MomJunction combines the best of both worlds as she writes health-based content based on scientific evidence. Sanjana is trained in classical... more

Dr. Prachi Benara

Dr. Prachi Benara has over a decade of experience as an infertility specialist. Having done her graduation and postgraduation in India, Dr. Prachi trained in reproductive medicine and IVF in the UK. In addition to a one-year PG diploma, she worked as an observer in the Oxford University Hospitals and trained in IUI, ultrasound, and embryo transfer at the British... more