What Does Effacement Mean?

Team Peanut7 days ago4 min read

Cervical effacement is part of the grand finale of your pregnancy.

Your belly has expanded farther than you thought possible. You’re swollen, maybe cramping, and exhausted—and if another person asks you if you’re having a boy or a girl, you might just get violent. Next exciting episode: how are you going to get this baby out?


Well, mama, the good news is that your body is very smart. It has all sorts of plans for the big day. And a major part of that is the thinning out (or effacement) of the cervix.

What is effacement?

Cervical effacement is a big part of the vaginal birth equation. But while you may have heard the term tossed around on Peanut and in other mom groups, what is it exactly? How is it measured? And what do those measurements mean for you and your baby’s entrance into the world?

Cervical effacement definition

Cervical effacement is the thinning, shortening, and softening of the cervix. This, along with contractions and cervical dilation, is one of the tricks your body performs so that your baby can go through the vaginal canal with (ahem) ease.

Your cervix is the connecting point between your uterus and your vagina. Its normal job is to be the bouncer at the door of your uterus. It decides what goes in and out.

It looks like a long-ish neck—in Latin cervix uteri literally means “the womb’s neck”—and has the responsibility of letting sperm in and period blood and babies out.

When you’re not pregnant, your cervix is firm and long (about an inch or so) and takes its job of gatekeeper very seriously. But when it starts to realize that there’s a baby that needs to get out, it knows to open up the exit routes.

To accomplish this, your cervix does two things: it dilates (opens) to about the size of a drinks coaster, and it effaces (thins and shortens).

How long after effacement does labor begin?

Our bodies are all on their own schedules, so there’s no one simple timeline here. Sometimes 24 hours, sometimes days.

Is effacement one of the signs of labor?

No, not necessarily. Your cervix may get going on the process a few weeks before you give birth. Or, because bodies all keep their own timelines, the whole process can happen in a few hours before you go into labor.

Can you be 100% effaced and not in labor?

Yes. The funny thing is that your cervix may complete the effacement process without any fanfare (self-effacing anatomy part that it is), and you may not even know that it’s happened. You may feel some discomfort and mild contractions, but this is not the case for everyone.

But there are a couple things you might notice as your cervix effaces. All that work that your cervix is doing results in the loss of the mucus plug, that protective layer that has been sealing the uterus off during pregnancy. Also, this is when the bloody show happens, that delightful blood-tinged discharge that makes its way out of your vagina as you prepare for labor.

What does it mean to be 80% effaced?

You’re almost there. Basically, this means that the process is 80% complete. Breathe, mama. The final stretch (literally…) is in sight.

If you are giving birth vaginally, the cervix should be 100% effaced (like strand-of-hair kind of thin) and dilated to about 3.9 inches (coaster/bagel/grapefruit size).

In some cases, effacement can happen too early, leading to preterm delivery. By looking at the size and makeup of your cervix ahead of time, your doctor may be able to flag this early on. If so, they might monitor you more closely in the later stages of your pregnancy to see if there are signs that your little one wants to make an early appearance.

Best of luck, mama. So close now!