What Is Cervical Effacement?

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Effacement is the process of the cervix thinning, shortening, and softening to open the vaginal canal for childbirth. During pregnancy, the cervix is usually long, thick, and closed. The cervix helps to keep the baby secure and safe from germs getting into the uterus that could cause an infection.

In preparation for childbirth, the cervix must thin (efface) and open up (dilate) to allow the fetus to pass from the uterus through the vagina. Read on to learn more about effacement throughout late pregnancy and labor, how it’s measured, and how long the process might take.

Black doctor examining pregnant patient's belly


Ariel Skelley / Getty Images

What Role Does Effacement Play in Labor?

Effacement and dilation are direct results of effective uterine contractions. If it's your first labor, it may last longer than those who have had previous births, but first-time laborers tend to efface before they dilate. In later pregnancies, effacement and dilation usually happen together and more quickly.

In the weeks leading up to your due date, your doctor may make a guess on how close you are to delivering based on your cervix. It's worth noting that cervical effacement can start a few weeks before labor. Once your cervix is fully effaced, delivery is likely to be close.

Effacement vs. Dilation

Effacement and dilation are different processes that happen at the same time:

  • Effacement refers to the thinning, softening, and shortening of the cervix.
  • Dilation is measured in centimeters and your cervix must dilate from 0 to 10 centimeters to enable vaginal delivery.

The more effaced the cervix is, the faster dilation happens.

Signs of Effacement

You may or may not have symptoms as your cervix effaces. Some people feel nothing at all.

Some possible symptoms of effacement include:

  • Braxton Hicks contractions, also known as practice contractions or false labor. They do not cause dilation but may help to soften the cervix.
  • You lose your mucus plug
  • An increase in vaginal discharge
  • Feeling like your baby has dropped lower into your pelvis

Bear in mind that these are common sensations at the end of your pregnancy.

It may be difficult to pinpoint whether what you’re feeling is due to dilation, effacement, labor, or just general pregnancy pains.

Measuring Effacement

Effacement is measured in percentages ranging from 0 to 100%. When you are 0% effaced, your cervix is about 3 to 4 cm long and thick. When you reach 50%, your cervix is about half the size and thickness it was before. When the cervix feels as thin as paper, you are 100% or fully effaced. Once effacement is complete, the cervix can fully dilate or open up for birth.

At your prenatal visits near the end of your pregnancy, your healthcare provider will examine you to see if your body is beginning to prepare for labor. They will feel your cervix to check for the following signs of labor:

  • Opening (dilation)
  • Position (movement toward the front of the vagina)
  • Shortening
  • Softening (ripening)
  • Thinning (effacement)

Once you're in labor, your healthcare provider will check your cervix regularly to keep track of how effaced and dilated you are as you get closer to delivering. 

Can I Measure My Own Effacement?

You can check your own cervix, but if you are not familiar with how it felt before pregnancy, it may be difficult to recognize the changes. Your healthcare provider has more training to determine exactly how effaced you might be.

Complications

Effacement is a normal part of the labor and delivery process. It usually begins on its own when your body is ready for childbirth. However, if it starts too early in pregnancy or is not starting when a pregnancy is overdue, it can lead to complications.

Early Effacement

When the cervix is shorter than normal or not strong enough to stay closed during pregnancy, it can begin to efface and open up too early, which could lead to preterm labor or premature birth.

Causes of early effacement include:

  • Your cervix is shorter than average
  • Your cervix is weak (incompetent cervix)
  • You had surgery on your cervix
  • You had an injury on or near the cervix
  • You have a genetic issue with the cervix

Your doctor can diagnose a short or weak cervix by reviewing your medical and pregnancy history, conducting a physical exam, and doing an ultrasound of the cervix.

The treatment for an incompetent or short cervix includes:

  • Cerclage: Which is a procedure that stitches your cervix closed to keep it from opening up during pregnancy. Doctors usually perform a cerclage at 12 to 14 weeks of pregnancy. The stitches are typically removed around week 37.
  • Monitoring: If the doctors feel that your cervix may thin and open early, they will monitor your cervix during your pregnancy. 
  • Progesterone: Studies show that when prescribed from week 16 to week 36, progesterone can help prevent premature delivery.

Late or No Effacement

When effacement and dilation do not happen on their own, the doctor may want to induce labor. There are several medicines and medical devices the doctor can use to help the body to efface and get labor started, including the following:

  • Catheter: Using a thin tube that has an inflatable balloon on the end to gently stretch the cervix.
  • Prostaglandins: A type of medicine placed into the vagina or taken by mouth to help soften or ripen the cervix.
  • Stripping membranes: Gently sweeping over the membranes to slightly separate them from the bottom of the uterus and release natural prostaglandins. 
  • Rupturing the amniotic sac: To rupture the amniotic sac, your healthcare provider makes a small hole in the sac with a special tool. Most people go into labor within hours after the amniotic sac breaks.

How Long Does Effacement Take?

Unfortunately, there's no set time for how long effacement should take. Everyone experiences it differently. For some, the cervix can begin to soften and thin out days or weeks before delivery. For others, it may not happen until labor begins.

A Word From Verywell

Cervical effacement is an exciting sign that your body is preparing for childbirth. Sometimes effacement can start too early and need to be stopped, or it can be slow to happen and require a little assistance from your doctor or midwife to move things along. Most of the time, effacement happens on its own, when your body and baby are ready.

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