As pregnancy nears its conclusion, the body undergoes a series of transformations to prepare for childbirth. One such change is cervical effacement, a natural and gradual process that indicates the cervix is getting ready for delivery. This article explains cervical effacement, particularly in late pregnancy, and what it signifies for expectant parents.
Understanding Cervical Effacement
Cervical effacement refers to the thinning and shortening of the cervix, the lower part of the uterus that connects to the vagina. Throughout most of pregnancy, the cervix remains long, firm, and closed. As the body prepares for labor, the cervix begins to soften, thin out, and shorten. This process is also known as cervical ripening.
Effacement is measured in percentages, ranging from 0% to 100%. A cervix that is 0% effaced is thick and long, while a 100% effaced cervix is thinned out. This thinning allows the cervix to become part of the lower uterine wall, ultimately enabling the baby to pass into the birth canal. Healthcare providers typically assess effacement through a manual examination, estimating the percentage based on how thin the cervix feels.
What to Expect at 36 Weeks
At 36 weeks of pregnancy, there is a wide range of normal effacement that individuals may experience. Some pregnant individuals may have no effacement at all, remaining at 0%, while others might be significantly effaced, even up to 80% or 90%. This variability means that a specific effacement percentage at 36 weeks does not reliably predict when labor will begin. It is possible to be partially effaced for weeks before active labor starts.
The degree of effacement at this stage is simply one piece of information a healthcare provider considers when assessing the progression of pregnancy. For instance, some individuals at 36 weeks might be 1 centimeter dilated and 75% effaced, while others may be 0% effaced and not dilated at all. The baby’s head dropping deeper into the pelvis, known as “lightening,” can also occur around 36 weeks, which helps push against the cervix and contribute to effacement.
Effacement and Labor Progression
Cervical effacement plays a significant role in the broader context of labor, working in conjunction with dilation. Dilation refers to the opening of the cervix, measured in centimeters from 0 to 10. For a vaginal delivery, the cervix must be 100% effaced and 10 centimeters dilated. While these two processes typically happen together, effacement often precedes significant dilation.
Effacement can begin weeks before active labor truly starts. Early, mild contractions, often referred to as Braxton Hicks, can contribute to cervical changes, helping the cervix to soften and thin. However, these practice contractions are different from the strong, regular contractions of true labor that cause consistent cervical change.
When to Consult Your Healthcare Provider
While effacement is a normal and expected part of late pregnancy, it is not typically a reason to contact a healthcare provider on its own. Instead, individuals should focus on other symptoms that are more indicative of impending labor or potential concerns. It is important to call a doctor or midwife if regular, painful contractions begin that occur frequently and consistently, or if the water breaks.
Other symptoms that warrant immediate medical attention include heavy vaginal bleeding, severe abdominal pain, or a noticeable decrease in the baby’s movements. Any sudden, severe swelling in the hands, face, or feet, persistent headaches, or vision changes should also prompt a call to a healthcare provider. Always seek personalized medical advice if any symptoms cause concern.