What is cervical dilation and effacement?

Cervical effacement and dilation mark the first stage of labor. In most cases, they’re a sign that it’s time to get in touch with your healthcare provider and put your birth plan into action. When it happens earlier than 37 weeks of pregnancy, on the other hand, the next steps get a bit more complicated.

What does effacement and dilation look like?

Effacement happens when the cervix, which is the bottom part of the uterus where it meets the vagina, begins to thin, and dilation happens as the cervix starts to open. This happens as the baby drops down past the pelvis and starts putting more and more pressure on the cervix. First-time moms generally efface before they dilate, while second-time-or-more moms often dilate before effacement. Either way, the cervix must be 100% effaced and 10 centimeters dilated before a mother can deliver vaginally at term. In preterm women, the cervix may not need to dilate completely.

Your healthcare provider will start to routinely check for effacement around 37 weeks of pregnancy, and if you show warning signs for preterm labor, they may begin to check earlier or more often with a speculum. If you start to have preterm contractions, your healthcare provider will monitor you through them, but if your cervix starts to dilate, there’s a good chance contractions won’t end on their own, and you may be moving into labor.

What happens if my cervix effaces and dilates early?

After 34 weeks, if the baby has grown to a certain size, and your body is starting to go into labor, your doctor may not try to stop labor, since babies at this age who have grown enough are generally born healthy even if they are early. If the baby is smaller, or you’re less than 34 weeks into your pregnancy, and you have no contraindications to medications that help decrease preterm contractions (i.e. high blood pressure or uterine bleeding), your doctor may give you medications to delay labor for up to 48 hours, and try to make sure the baby is as ready as possible to come into the world. This could include medications such as oral corticosteroids to help accelerate fetal lung maturation and reduce other complications associated with preterm birth.

Early effacement and dilation are one step along the path or early labor, but depending on when they happen, and when they are caught, there are different ways to manage them.

If your cervix begins to dilate and efface before 24 weeks, you may be a candidate for additional medications or procedures to help reduce the risk of preterm birth, like progesterone or cervical cerclage.

Reviewed by the Ovia Health Clinical Team

  • “Cervical effacement and dilation.” MayoClinic. Mayo Foundation for Medical Education and Research, 2016. Web.
  • Healthwise Staff. “Cervical Effacement and Dilatation.” UofMHealth. Regents of the University of Michigan, Nov 2011. Web.
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