What Is Cervical Effacement?

As labor approaches, your cervix is getting ready for the big day!
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Updated August 12, 2021
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There are certain terms most women don’t even know exist until they become pregnant—and cervical effacement is one of them. If your doctor mentions that you’re “effaced” during an appointment or in the delivery room, you’re probably going to want to at least have some clue as to what they’re talking about. So what is effacement, exactly, how will your doctor measure it and what’s the difference between effacement vs. dilation? We’re sharing everything you need to know about cervical effacement and why it matters in your labor and delivery journey.

What Is Effacement?

Effacement refers to the thinning of your cervix, the low, narrow end of the uterus that connects to the vagina, according to the American College of Obstetricians and Gynecologists (ACOG). Effacement is also sometimes known as the “softening,” “shortening” or “ripening” of the cervix. “The cervix is like a gatekeeper for the baby,” says Christine Greves, MD, an ob-gyn at Winnie Palmer Hospital for Women and Babies in Orlando, Florida. “When it starts to become thinner, or effaced, it tells us that the body may start preparing itself for delivery.” During pregnancy, the average cervical length is about 3 to 4 cm. By the time you’re fully effaced, your cervix will be as thin as a sheet of paper.

What does ‘effaced’ mean?

As you progress through labor, you may be told you’re 50 or 100 percent effaced—but what does “effaced’’ mean? The word “effaced” refers to something being diminished or eliminated. In the same vein, doctors use it as a medical term to describe the thinning out of your cervix, says Lisa Thiel, DO, an ob-gyn specializing in maternal-fetal medicine at Spectrum Health. “A cervix is typically long and thick and it will need to soften, dilate and also thin or ‘efface,’” she says.

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Effacement is described in percentages from 0 to 100 percent, where the cervix is long and thick at 0 percent and very thin and ready for delivery at 100 percent effacement, Thiel explains. Your doctor will probably start checking your cervix for effacement and dilation around week 36 of pregnancy.

Doctors measure effacement by feeling your cervix, says Greves. “We use our fingers and determine the effacement by centimeters or percentages,” she says. “You can feel it and assess the thickness by putting your fingers in and feeling how thick the cervix is against the head of the baby.”

There’s no precise way for doctors to know exactly what percent effaced you are at any given moment—they can just estimate it by feel. Because of this, “if you have the same provider measuring it, you can get a more accurate measure,” says Michael Cackovic, MD, a maternal-fetal medicine physician at Ohio State University Wexner Medical Center. There’s no definitive gauge, so doctors may measure differently.

Effacement vs. Dilation: What’s the Difference?

Effacement is a measure of how thin your cervix is, but dilation is how much your cervix has widened, says Melissa May Deer Pelletier, DO, an ob-gyn at Northwestern Medicine Central DuPage Hospital. “Dilation is the opening of the cervix from closed—0 centimeters—to fully dilated—10 centimeters,” Pelletier explains. “We can’t talk about effacement without talking about dilation, as they work together during labor,” she says. “The uterus needs to have regular contractions that allow pressure to be placed on the cervix, which will thin (efface) the cervix and open (dilate) the cervix.” Care providers generally want your cervix to be 100 percent effaced and 10 centimeters dilated before you start pushing, Pelletier says.

Cervical Effacement Symptoms

You can’t feel your cervix thinning, but you might pick up on a few cervical effacement symptoms. When your cervix effaces, you may feel pressure down there, Thiel says. You might also notice an increase in cervical mucus or discharge. “It may feel kind of crampy,” Cackovic says. “Not like a true labor pain, but more like a menstrual-type pain.” It’s also possible that you may not notice anything, Pelletier says.

Potential cervical effacement symptoms include:

  • Braxton hicks contractions. While these practice contractions won’t dilate the cervix, they may help to soften or ripen (aka efface) it.
  • Pelvic pressure. The pressure from baby’s head could contribute to the thinning of your cervix and may cause some discomfort.
  • Loss of mucus plug. If you’re having a significant amount of discharge, it may be the result of effacement.

How Long Does Effacement Take?

Has your doctor told you you’re slightly effaced? That’s exciting news—but if you’re wondering “how long does effacement take?,” the answer is somewhat less encouraging. Suffice to say, it depends. As with most things related to labor, it can be slow and steady, fast and furious or somewhere in between. “Every patient has a different experience with timing of cervical change,” Thiel says. “Some pregnant patients have a thin cervix and stay dilated for weeks at a time before contractions and labor develop. Other patients have a long and thick cervix and progress into labor very quickly, over a few hours.”

There’s not really anything you can do on your own to speed up effacement, but your doctor may consider using certain medications if your cervix isn’t effacing quickly enough or if you’re induced, Thiel says. “Many of the medications are given orally, vaginally or in an IV,” she says.

While you may find some DIY tricks for accelerating effacement online, Pelletier says they don’t really do anything. “Beyond medical interventions offered during an induction process, there isn’t much evidence to support other methods to speed up effacement while waiting for labor to happen once a patient is 37 weeks or after,” she says.

Can you be effaced but not dilated?

Cervical effacement and dilation go hand in hand; you need both to happen in order to deliver baby vaginally. But they don’t always occur at the same time. So, yes, it’s possible to be effaced but not dilated, Thiel says. (You can also be dilated but not effaced.)

“Typically, first time moms will efface and then dilate, whereas moms who have had vaginal deliveries or dilated before can dilate before their cervix will efface,” Pelletier says.

Cervical effacement gets you closer to labor and delivery. It might be a quick process or a gradual one; there’s really no telling how soon you’ll be fully effaced. Try to be patient and listen to your body. It won’t be long now!

About the experts:

Michael Cackovic, MD, is a maternal-fetal medicine physician at The Ohio State University Wexner Medical Center. He received his medical degree from the MCP Hahnemann University College of Medicine in Philadelphia, Pennsylvania.

Christine Greves, MD, is an ob-gyn at the Winnie Palmer Hospital for Women and Babies in Orlando, Florida. She earned her medical degree at the University of South Florida College of Medicine in Tampa.

Melissa May Deer Pelletier, DO, is an ob-gyn at Northwestern Medicine Central DuPage Hospital. She received her medical degree at Des Moines University College of Osteopathic Medicine in Iowa.

Lisa Thiel, DO, is an ob-gyn specializing in maternal-fetal medicine at Spectrum Health. She received her medical degree from the Philadelphia College of Osteopathic Medicine in Pennsylvania.

Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.

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