Measuring Cervical Dilation: Common Methods & Effacement FAQ

| Reviewed By Sarah Schulze, MSN, APRN, CPNP

Although cervical dilation cannot accurately predict when your baby will be born, it can give doctors information about the progress of labor. Different methods for measuring cervical dilation are available depending on the desired level of detail.

Can you see cervical dilation on an ultrasound? If your doctor uses a transvaginal ultrasound, then cervical dilation can be seen. Although most doctors just do cervical checks with their fingers rather than an ultrasound, some want a more precise measurement. A transvaginal ultrasound can offer this.

There is plenty to understand about dilation and effacement and what it does or doesn’t mean for labor.

Measuring Cervical Dilation

Cervical dilation can be measured in more than one way.

How Is Cervical Dilation Measured?

There are two main methods that doctors use to find out if you are in the process of dilating: a digital cervical exam and a cervix measurement via ultrasound.

Digital Cervical Exam

A digital cervical exam is the most common method doctors use to measure cervical dilation. Simply put, the doctor uses fingers to measure dilation.

The provider inserts one or two fingers inside the vagina and roughly estimates how open the cervix is based on how far apart their fingers measure and if one or two fingers fit.

Cervix Measurement Ultrasound

A transvaginal ultrasound can offer another way to check dilation. Ultrasound images can provide an image of cervical thickness and dilation.

When Does Your Doctor Start Checking for Dilation?

Current evidence states that routine cervical checks are not necessary as part of prenatal care and are not an accurate prediction of pending labor.

Unnecessary cervical checks also increase the risk of introducing bacteria into the uterus or prematurely breaking a mother’s water. Frequent and early cervical checks can also increase a mother’s anxiety unnecessarily if she becomes preoccupied with how far dilated (or not) she is. 

Cervical checks may be needed if a woman is experiencing symptoms of labor prematurely or if induction is being planned in order to determine induction methods needed. Cervical checks during a normally progressing labor may be useful to monitor progress if the mother desires, but are not necessary and can be declined.

Does It Hurt When They Check for Dilation?

Checking for dilation can be uncomfortable, but it should not be painful if your doctor or midwife is gentle and careful.

You may be more sensitive in the vaginal area during pregnancy, so you will likely feel more intense sensations. However, cervical checks should not take long.

How Long Does It Take To Dilate From 1 to 10?

How long it will take you to go from 1 to 10 when dilating is anyone’s guess.

Some women start dilating and progress to a 10 within minutes or hours. Others can take weeks to go from 1 centimeter to 2. There’s no way to predict progress accurately.

10 Centimeters Dilated – How Long Till Birth

Once you make it to 10 centimeters dilated, it is not necessarily time to push. The baby’s “station” or how far down into the birth canal the baby also needs to be taken into account.

If you are fully dilated but not feeling a strong urge to push or your provider says the baby is still high up, you can continue walking, using a peanut ball, or waiting however you are most comfortable for your baby to descend further and be ready to make their arrival.

When you are fully dilated and your baby is in the optimum position to push, you will likely feel a strong sensation of pressure, like you need to have a bowel movement. This means it is time to start pushing.

Depending on your position and baby’s it can take just a few pushes, or sometimes much longer. Your doctor or midwife will monitor your progress and the baby’s well-being and help guide you.

A laboring woman being tended to by nurses in a hospital.

Understanding Cervical Effacement

While cervical effacement can’t predict exactly when your baby will arrive, it can offer clues as your body is preparing for labor.

Difference Between Cervical Effacement and Dilation

Cervical effacement and dilation are not the same. Cervical effacement means that your cervix is shortening and getting thinner. Cervical dilation means your cervix is opening. Both are important and necessary.

Cervical Effacement Symptoms

Though you won’t know how far effaced you are until your doctor checks, there will be signs that effacement has started. They include:

  • More vaginal discharge than usual
  • Mucus plug falling out
  • Your baby dropping
  • Practice contractions, also known as Braxton hicks

Can an Ultrasound Show Effacement?

A transvaginal ultrasound can show effacement, and it may give more accurate information than a digital cervical exam. However, not every doctor will choose an ultrasound to check for effacement.

How To Measure Cervical Effacement

When measuring for cervical effacement, your doctor is trying to determine how soft and thin your cervix is.

If your cervix is hard and feels extremely thick, you either haven’t started effacement or you aren’t very far along in the process. A soft, thin cervix is a sign that effacement is progressing.

Effacement is measured in percentages. A 0% effaced cervix is very long or thick, like the neck of a soda bottle. As the cervix thins out, the percentage increases until 100% effaced when the cervix is nearly flat.

How Long Does Effacement Take?

Just like dilation, effacement doesn’t happen at the same rate for each person. You may not be fully effaced until you are in active labor, or you may start the effacement process days before you start labor.  

Signs of Dilation and Effacement

Not every person has signs that they are dilating or effacing, but most people notice some. They may include:

  • Vaginal discharge
  • Water breaking
  • Loss of mucus plug
  • Contractions

How To Check Dilation Without Internal Exam

While an internal exam using an ultrasound is considered the most reliable way to check dilation, there are less invasive ways to get an idea of where you are in terms of labor. 

You may notice the following:

Your Sounds

It might be hard for you to notice while you are in labor, but the more your labor progresses, the more the sounds you make will change. As you near birth, you may sound more primal, with moans taking the place of words. 

Odd Comments

As a woman transitions into the final stages of labor and becomes fully dilated, she may not make much sense because her thoughts will become irrational.

This can lead to her not believing she’s in labor or wanting to go home before the baby is born. 

Related Questions: 

I’m 70% Effaced – How Much Longer?

Unfortunately, there’s no one answer to this question. While being 70% effaced means your body is definitely preparing for labor and delivery, it doesn’t predict when you will actually start laboring.

Some women get to 70% effacement in a matter of hours and keep going until they are 100% effaced and ready to push.

For others, cervical effacement can be a process that takes weeks to progress. Being 70% effaced does not predict when your baby will arrive.

What’s the Average Delivery Time for First Baby?

For a first baby, you are looking at anywhere from 12 hours to a full 24 hours of labor before you see your baby’s face. Every person is different, and some babies come out much faster than others. 

Closing Thoughts

Cervical dilation and effacement can’t predict everything about labor and delivery, but they can offer your doctor information that will guide them in making decisions about your pregnancy and upcoming birth.