Effacement is the thinning and shortening of the cervix. It happens at the end of pregnancy in preparation for childbirth. A pregnant person must be 100% effaced for a vaginal delivery.
Cervical effacement (or ripening) is when the cervix softens, thins and shortens. It happens late in pregnancy as your body prepares for labor and delivery. Your cervix will eventually thin out and open (dilate) enough for your baby to pass through your vagina.
To understand effacement, it’s helpful to know what your cervix is and how it changes as you get closer to delivering your baby. Your cervix is long, firm and closed during pregnancy. It’s located at the bottom of your uterus. The fetus grows inside your uterus.
Before you efface, your cervix is like the neck of a bottle. The “bottleneck” at your cervix prevents the fetus from sliding down into the birth canal and protects the fetus from infection during pregnancy. Your cervix is about 4 centimeters long during pregnancy. It extends down into your vaginal canal almost like a cork extends down into a bottle of wine.
As you get closer to delivery, your uterine muscles will contract (or tighten) to help drop or engage the fetus’s head into your pelvis. This pressure causes your cervix to go from hard and long to soft and short. By the time your cervix is completely or fully effaced, it’s as thin as a piece of paper. Your cervix is no longer acting as a cork in a bottleneck. Instead, the cervix has shortened and is drawn up towards your uterus.
Your healthcare provider may check your cervix with gloved fingers once you’re full term (around 37 weeks in pregnancy) to measure effacement. Measuring effacement gives your provider an indicator of where you are in labor. Unfortunately, it can’t tell them for certain when you’ll go into labor.
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Effacement is measured in percentages. For example, 0% effaced means you haven’t effaced at you’re your cervix is still long and firm. When your cervix has completely thinned, you’re 100% effaced. When you’re 100% effaced, it means your cervix can’t thin or shorten any further.
Dilation is when your cervix opens. It’s measured in centimeters. If your cervix is completely closed, you’re 0 centimeters (cm) dilated. You’re fully dilated once your cervix is 10 cm wide. At 10 cm, your cervix is as wide as a small cantaloupe.
Cervical dilation and effacement go hand in hand. Like effacement, dilation is also caused by uterine contractions. Your cervix must be 100% effaced and 10 cm dilated before the pushing stage of a vaginal delivery can begin.
Yes, it does mean you’re close to labor, but no one knows exactly how close. In early labor, you will experience contractions (tightening of your uterine muscles). These contractions are mild and irregular and can last several hours or days. Don’t be discouraged: Those early contractions are helping to efface and dilate your cervix.
As your cervix prepares for delivery, pressure from the contractions causes it to stretch and thin. During pregnancy, your cervix has been plugged by a glob-like piece of mucus called your mucus plug. As your cervix stretches and thins, your mucus plug is loosened and passes through your vagina. Your mucus plug may be tinged with blood and may contain your bloody show. All of these signs mean labor will begin soon, and you’re one step closer to delivering your baby.
Most people don’t know their cervix has effaced. You may suspect your cervix is changing because you have other labor symptoms. Some of the signs of cervical effacement are:
All of these symptoms are signs that labor is near. Some people feel some of them, while others feel none. It can be tough to figure out if effacement has begun unless your healthcare provider checks your cervix. Only your healthcare provider can tell you if effacement has started. Trying to check yourself for effacement can be hard when you aren’t trained to perform cervical checks.
Braxton Hicks contractions will not make your cervix change or efface. Braxton Hicks are practice contractions or your body’s way of preparing for real contractions. Real labor contractions cause your cervix to efface and dilate. Braxton Hicks contractions can begin as early as mid-pregnancy and aren’t the same as a real labor contraction.
Effacement of 80% means you’re only 20% away from being completely effaced. Another way to think of it is you’re 80% done with the effacement process.
Yes, you can be effaced and not dilated. If this is your first baby, chances are you’ll efface before you dilate. You can also be dilated and not effaced. This is more common in second or third pregnancies. Some people’s cervix will efface and dilate at the same rate.
Everyone’s cervix is different. For example, it’s not uncommon for a pregnant person to be 2 cm dilated and 30% effaced for weeks. For others, they remain 0% effaced, and 0 cm dilated until a few days before delivery.
Effacement isn’t a reason to call your doctor. It’s a completely natural process that must occur before a vaginal delivery. However, you should call your healthcare provider if you think you might be in labor.
Additionally, any of the following symptoms could be a sign of a complication:
Yes, there can be complications that either slow down or speed up your cervix’s ability to efface.
Getting up and moving around may help speed up effacement when it’s moving slowly. Some reasons for slow effacement are:
On the other hand, some people’s cervix effaces too soon. This leads to premature birth. Some reasons for early effacement are:
Before the fetus drops lower into your pelvis, you may feel it up higher in your rib cage. Once its head drops deep into your pelvis, you may feel pressure and cramping in your lower abdomen rather than pressure in your ribs. The term “lightening” describes feeling “lighter” now that the fetus isn’t putting pressure on your diaphragm.
Like most things related to pregnancy and labor, there’s no way to be sure. Some people’s cervixes will be firm and closed right up until active labor begins. For others, they may be slightly effaced and dilated for several weeks. One thing is for sure: You have to get to 100% effacement if you want the next stage of labor to begin. Most of the time, a person will fully efface before they fully dilate.
A note from Cleveland Clinic
Effacement is when your cervix begins to thin out in preparation for childbirth. It’s measured in percentages. Before you start to push in a vaginal delivery, you have to be 100% effaced. Cervical effacement can be exciting because it means labor and delivery are coming soon. Your healthcare provider can check your cervix for effacement to see how your labor is progressing. People efface at different rates, so don’t be discouraged if you are near your due date and still 0% effaced. In most cases, effacement happens when your baby is ready.
Last reviewed by a Cleveland Clinic medical professional on 05/27/2022.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy