Feeling the baby’s head during a late-pregnancy cervical exam often leads to confusion about cervical effacement. These checks are designed to give a snapshot of the body’s readiness for labor, but the terms used—effacement and station—describe two distinct processes. Understanding the difference between these measurements is key to interpreting progress near delivery. The physical finding of the baby’s head relates to station, while effacement is an entirely separate assessment of the cervix itself.
The Three Key Measurements of Cervical Change
A routine cervical examination performed by a medical provider uses three distinct measurements to assess the progress toward labor. The first is Dilation, which measures the opening of the cervix in centimeters, ranging from zero (closed) to ten (fully open). Ten centimeters of dilation is required before pushing the baby can begin.
The second measurement is Effacement, which describes the thinning, softening, and shortening of the cervix. Before labor begins, the cervix is typically long and thick, measured at 0% effaced. It must shorten and thin to 100% effacement to allow the baby to pass through. Thinking of the cervix like the neck of a balloon, effacement is the process of that neck being pulled up.
The third measurement is Station, which assesses the baby’s position within the pelvis. This number describes how far the baby’s head, or other presenting part, has descended into the birth canal relative to a specific bony landmark. These three numbers—dilation, effacement, and station—provide the most complete picture of cervical readiness.
Understanding Fetal Station and Engagement
When a doctor feels the baby’s head during a vaginal exam, they are assessing the Fetal Station. This measurement tracks the baby’s descent into the pelvis, not the condition of the cervix. Station is measured on a scale from -5 to +5, with each number representing a centimeter above or below a fixed point in the pelvis.
The anatomical landmark defining the zero point, or Station 0, is the ischial spines, which are bony protrusions located in the narrowest part of the pelvis. When the baby’s head is level with these spines, the fetus is considered “engaged” in the pelvis. A negative number, such as -3, means the head is still high up in the pelvis, while a positive number, such as +2, means the head has descended past the spines and is closer to the vaginal opening.
If your provider states they can feel the baby’s head low, they are confirming a low or positive fetal station, indicating significant descent. This physical finding is a direct observation of the baby’s position in the birth canal. It is an indication of the baby’s engagement.
Do Station and Effacement Happen Simultaneously?
A low fetal station and high effacement are both signs of labor readiness, but they are independent processes that do not necessarily happen at the same time. Effacement is the thinning of the cervix, driven by hormonal changes and uterine contractions. Station is the baby’s physical descent into the pelvis, influenced by gravity and the force of contractions.
In first-time mothers, the cervix often effaces significantly before the baby’s head fully engages and descends to Station 0. However, in people who have given birth before, the baby may drop much earlier, resulting in a low station even when the cervix is still thick. It is entirely possible to be 100% effaced with the baby still high at a -2 station, or to have a baby at Station 0 with only 50% effacement.
This lack of required correlation means that feeling the baby’s head does not automatically confirm high effacement. The two measurements simply track two different aspects of the body preparing for delivery. Both processes must eventually reach their maximum point—100% effacement and a +5 station—for birth to occur.
Interpreting Your Cervical Exam Results
The combination of dilation, effacement, and station provides a comprehensive assessment of your body’s current readiness, often summarized using a scoring system like the Bishop score. These numbers are indicators of physical change but are not a precise timeline for the onset of labor. A person can walk around for days or even weeks with significant dilation and effacement before active labor begins.
Conversely, a person can have minimal findings—a closed, thick cervix with a high station—and go into active labor within hours. The rapid and unpredictable nature of labor means that any cervical exam is only a snapshot of a single moment in time. These measurements are most valuable when a provider is assessing the likelihood of a successful labor induction or tracking the progress during active labor.
It is important to discuss the specific findings of your cervical exam with your medical provider. Understanding your unique combination of dilation, effacement, and station allows for an informed conversation about the next steps. While the numbers are encouraging signs of progress, they should be viewed as markers of readiness, not a definitive clock counting down to delivery.