Mucus Plug: What it Looks Like & When Labor Starts

May 2022

A mucus plug is a substance produced by the body during the first months of pregnancy. It serves to prevent bacteria and other microorganisms from reaching the uterus and interfering with fetal growth and pregnancy progression. The mucus plug is found right after the vaginal canal and closes off the uterus. In low-risk pregnancies, it statys in place until the baby is ready to be born. 

When the mucus plug is eliminated vaginally, at around 37 weeks, it signals that the end of pregnancy is near and that labor can start in days to weeks. The plug usually has a jelly consistency and the color can vary from clear to a reddish-maroon color. 

After it falls out, it is common to feel hardening of the belly throughout the day. This is usually a sign of early labor. 

What a mucus plug looks like 

When it dislodges from the uterus as a whole piece, the mucus plug looks like light-colored egg whites and is about 4 to 5 cm in length. It can vary in shape, texture or color, even in a low-risk pregnancy. The mucus plug may have the following characteristics: 

CharacteristicExamples
Shape

- Whole

- In pieces

Texture

- Egg whites

- Firm, like Jello

- Soft, like jelly

Color

- Clear

- White

- Yellow

- Red

- Darker maroon tones 

Because the appearance of a mucus plug is pretty specific, it is usually not confused for amniotic fluid. Eliminating the plug is generally not painful and occurs about 3 weeks before the due date.

What happens when it comes out 

The mucus plug is most commonly eliminated between 37 to 42 weeks. In more rare cases, is eliminated during labour or during delivery.

Can a mucus plug fall out too early? 

When the mucus plug comes out earlier on in the pregnancy, it is usually not a sign of any issue. It may indicate that body is adapting to pregnancy-related changes. Although the baby is more susceptible to infections during this time, the body will regenerate a mucus plug quickly to protect the uterus. 

Therefore, if the mucus plug comes out or you notice pieces of it with wiping, you should not worry. Nonetheless, you should still inform your obstetrician so that you can be assessed for any risks. 

If your mucus plug is eliminated after the second trimester but before 37 weeks, you should seek medical attention immediately, as you are at risk for premature labor. 

What to do after you lose your mucus plug 

Once the mucus plug has been eliminated, you are advised to monitor for any other signs of labor, like loss of amniotic fluid and frequent, regular contractions. Keep in mind that losing your mucus plug does not necessarily indicate that labor is starting, as it can take up to 3 weeks for it to start. 

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Edited by Tua Saude editing team in May 2022. Medical review completed by Dr. Sheila Sedicias - Gynecologist in April 2022.

References

  • NHS. Signs that labour has begun. Available on: <https://www.nhs.uk/conditions/pregnancy-and-baby/labour-signs-what-happens/>. Access in 12 Aug 2020
  • NHS. What happens during labour and birth. Available on: <https://www.nhs.uk/conditions/pregnancy-and-baby/what-happens-during-labour-and-birth/>. Access in 12 Aug 2020
Medical review:
Dr. Sheila Sedicias
Gynecologist
Physician graduated in Mastology and Gynecology by UFPE in 2008 and member no. 17459 of CRM-PE, Brazil.