A Guide to The First Stage of Labor: Effacement and Dilation

Updated: February 16, 2021
It's important to be knowledgable of your pregnancy. Learn about what to expect during the first stage of labor, including effacement and dilation.
The First Stage of Labor

The stages of labor and birth are part of an amazing and seemingly miraculous process. Though there are differences and beauty in all of the various ways that women arrive at motherhood, it is helpful to understand the typical process of how the body progresses through the stages of labor to ready itself for birth.

More: What Do Labor Contractions Really Feel Like?

Every pregnancy and labor and delivery is unique, including the length of time it takes to move from one stage to another. This ultimate guide to effacement and dilation will help you to understand the stages of labor and what is actually happening to the body during both early labor and active labor:

The Stages of Labor

The first stage of labor is the dilation and effacement of the cervix. Parents.com provides these helpful comparisons to help you visualize this initial process:

  • 1 cm dilated: Cheerios
  • 2 cm dilated: Grape
  • 3 cm dilated: Banana Slice
  • 4 cm dilated: Cracker

After this time, the cervix moves into what is considered the active phase where contractions are usually three to five minutes apart.

The final stage of effacement and dilation is known as the transition phase, and this is the most intense time for most women. This is when the cervix completes effacing and dilating to a full 10 cm.

First Stage of Labor

The first stage of labor occurs when you typically begin to feel contractions. It is considered early labor when your contractions feel both mild and irregular. As your due date approaches, it is natural to want to be on the lookout for signs of labor. Other early signs of labor include when your baby drops, which means it descends into the pelvis. This can happen a few weeks before actual labor begins. You may also feel more cramps, increased back pain, and looser joints.

Early labor can vary from lasting just a few hours to several days. These early labor contractions may remind you of Braxton Hicks contractions which you may have felt as early as the midpoint of your pregnancy. The difference is that the Braxton Hicks contractions were more like a dress rehearsal for the real thing, and now you are about to start the show.

For your baby to be born, the cervix (composed of firm muscle that forms a strong base at the bottom of the uterus) needs to stretch and soften so that it can open, or dilate. This dilating process allows your baby to pass out of the uterus and into the vagina. Toward the end of pregnancy, substances in your blood called prostaglandins start to soften the cervix so that it becomes more malleable. Your baby also gets into "position" to make his way out.

One of the first signs of early labor is sometimes called a bloody show. This may happen when your cervix begins to open and the mucus plug that blocks the opening to the cervix dislodges. If you see a significant amount of blood or if your water breaks, you might consider reaching out to your healthcare provider right away to get their advice on next steps.

You may want to ask your healthcare provider for their medical advice relating to what point you may want to consider going to the hospital or reaching out to a doula or birth support team within the early labor process before labor begins so you have some benchmarks in mind. When early labor begins, many women choose to work on staying as relaxed as possible. They might practice breathing techniques, go for a walk, or experiment with sitting or moving in different positions.

Effacement

Effacement

While you are pregnant, your cervix is usually around 2 to 3 cm long. Cervical effacement is the shortening and thinning of the cervix. In what is typically the third trimester pregnancy, Braxton Hicks' practice contractions start to shorten the cervix, a process known as effacement. Most women have a cervix that has shortened to 1 cm during the very early stages of labor. This is also referred to as 50 percent effaced. As the cervix continues to shorten, the cervix is gradually drawn up by the uterus, and by the time it is 100 percent effaced, the cervix will have started to open.

"I always think about it as a pie chart. If you have 2cm (out of 10) dilated, you are 20% done with dilation. If you are 80% effaced, you are 80% done with effacement. It's important to know that for a cervix to dilate, it must first thin out (efface)," explains HeHe Stewart, a Birth and Postpartum Doula. "A pregnant person may walk around weeks effaced and dilated just a bit as their body prepares for labor. It's not uncommon to see someone be 2-3cm dilated and 50-60% effaced when labor starts.”

Dilation

Dilation

Once your cervix is stretched and softened, it begins to open, or dilate, so that your baby can pass through into the vagina to be born. Regular contractions cause the cervix to dilate, and in first labors the cervix dilates at an average of 1 cm per hour; this rate is often faster for subsequent labors. Here, at 2 cm dilation, the cervix has shortened and is beginning to open. Contractions may still be irregular.

Studies of the association of cervical effacement with the rate of cervical change in labor among nulliparous women, also known as women who have not given birth before, found that the rate of cervical dilation among nulliparous women is associated with not only the degree of cervical dilation, but also with cervical effacement. The study results also explain the associations of labor induction and augmentation on dilation and effacement. It is worth reviewing in case you are presented with the option to have your healthcare provider induce labor.

Dilation — 6 cm

Dilation - 6 cm

At 6 cm dilation, you are in active labor. Your contractions will be more frequent, regular, and stronger. Active labor is the process that the cervix goes through to dilate from 6 cm to 10 cm. This is typically the point in the labor process where women really need assistance as they face a new stage of challenge. Mayo Clinic suggests the following at this point:

“Look to your labor coach and health care team for encouragement and support. Try breathing and relaxation techniques to combat your growing discomfort. Use what you learned in childbirth class or ask your health care team for suggestions.

Unless you need to be in a specific position to allow for close monitoring of you and your baby, consider these ways to promote comfort during active labor:

  • Change positions
  • Roll on a large rubber ball (birthing ball)
  • Take a warm shower or bath
  • Take a walk, stopping to breathe through contractions
  • Have a gentle massage between contractions”

Dilation — 10 cm

Dilation - 10 cm

At 10 cm dilation, you are fully dilated. Contractions may be almost continuous and you are nearly ready to start pushing which will help your baby travel through the birth canal in a vaginal delivery. You will feel an overwhelming urge to push the baby out when it is time. Contractions may be 60 to 90 seconds apart.

The Station

The Station

The "station" refers to the position of your baby's head in relation to your pelvis. This is recorded as a number between -5 and +5. Zero station means the head is "engaged" and has entered the vaginal canal within the pelvic bones. A negative number (-5 to 0) means that the head isn't engaged in the pelvis. A positive number (0 to +4) means that your baby's head is moving down the pelvis and +5 means your baby is crowning (being born). Ideally, you should not push until the head is engaged in the pelvis, even if you're fully dilated.