As your due date approaches, you’ll hear more about dilation and effacement—two key factors that your healthcare provider monitors to determine how close you are to giving birth. These terms refer to the changes that your cervix undergoes in preparation for labor. Understanding what they mean and how they work together can help you feel more informed and ready for the big day.

What is Dilation?

Dilation refers to the opening of the cervix during labor. The cervix, which is usually closed, begins to open or dilate to allow your baby to pass through the birth canal. Dilation is measured in centimeters from 0 to 10:

• 0 cm means the cervix is completely closed.
• 10 cm means the cervix is fully open and ready for the baby to be born.

Dilation happens gradually, often beginning in the days or weeks leading up to labor. Some women may begin to dilate before feeling any contractions, while others may not dilate until they are in active labor.

How Dilation is Measured

Your healthcare provider will check your cervix during a vaginal exam to measure how dilated you are. This measurement helps them track the progress of labor and estimate how close you are to delivery.

What is Effacement?

Effacement refers to the thinning and shortening of the cervix. Normally, the cervix is thick and long, but as your body prepares for labor, it becomes thinner and softer. Effacement is measured in percentages from 0% to 100%:

• 0% effacement means the cervix is still long and thick.
• 100% effacement means the cervix is completely thinned and ready for delivery.

Effacement typically happens before dilation or alongside it, especially for first-time mothers. For some, effacement may begin several weeks before labor starts, while others may experience rapid effacement closer to delivery.

Signs of Effacement

You may not feel anything as your cervix begins to efface, but some women experience cramping or Braxton Hicks contractions as the cervix softens. Regular prenatal visits will allow your doctor to monitor this process.

How Dilation and Effacement Work Together

For a vaginal delivery to occur, both full dilation (10 cm) and complete effacement (100%) are necessary. Effacement allows the cervix to thin out so that dilation can occur more easily. As your cervix effaces and dilates, it gradually opens enough for the baby to pass through the birth canal.

• Early in labor, you may be partially effaced but not yet fully dilated.
• During early labor, your cervix dilates from 0 to 4 cm.
• Active labor is marked by dilation from 4 to 7 cm, with contractions becoming more intense and regular.
• By the time you're in transition, you’ll reach full dilation (10 cm) and be ready to push.

Dilation, Effacement, and Labor

The progression of dilation and effacement varies for each woman. Some women may experience slow dilation and effacement over several days or even weeks before labor begins. Others may progress rapidly once active labor starts.

Here’s a general timeline of cervical changes during labor:

• Early labor: Your cervix dilates from 0 to 4 cm and becomes increasingly effaced.
• Active labor: Your cervix continues to dilate to about 7 cm. Contractions become stronger, longer, and closer together.
• Transition: The final phase of labor, where your cervix dilates from 8 to 10 cm, is the most intense phase before pushing.

How Can You Encourage Dilation and Effacement?

While your body will naturally go through these changes at its own pace, there are a few ways to encourage progress once you're full-term (after 37 weeks):

• Walking: Movement and gravity help put pressure on the cervix, which may encourage dilation.
• Using a birthing ball: Sitting or bouncing gently on a birthing ball can help the baby move into a favorable position for labor.
• Staying hydrated: Dehydration can slow labor, so keep drinking water.
• Nipple stimulation: This can cause your body to release oxytocin, which may help start contractions.
• Sex: Semen contains prostaglandins that can help soften the cervix, and orgasms can stimulate uterine contractions.

When Should You Call Your Doctor?

If you’re in the final weeks of pregnancy and experience regular contractions or notice other signs of labor (such as your water breaking or bloody show), it’s time to contact your healthcare provider. They will likely check your dilation and effacement to assess how close you are to delivering.

Remember, while dilation and effacement give a good indication of labor progress, every woman’s labor is different. Some may dilate slowly, while others may progress quickly once labor starts. It’s all part of the unique and amazing process of bringing a new life into the world.