Cervical dilation is the opening of the cervix, the lower part of the uterus, as pregnancy progresses towards childbirth. Understanding this process, particularly around 36 weeks, can help expectant parents recognize their body’s readiness for labor. This article explains what cervical dilation entails.
Understanding Cervical Dilation
The cervix seals the uterus during pregnancy, protecting the developing baby. As the body prepares for birth, the cervix begins to thin and open. This opening, cervical dilation, is measured in centimeters (cm). A completely closed cervix measures 0 cm, while full dilation, indicating readiness for delivery, is 10 cm.
Cervical effacement, the thinning and shortening of the cervix, is another important change. During pregnancy, the cervix is usually thick, measuring about 3 to 4 cm in length. Effacement is measured in percentages; 100% effacement means the cervix has thinned completely, becoming as thin as paper. Both effacement and dilation work together to allow the baby to move into the birth canal.
Dilation at 36 Weeks: What It Means
Experiencing some cervical dilation at 36 weeks is common and normal. This indicates the body is beginning preparations for childbirth, though it does not necessarily mean labor is imminent. Many individuals may experience slight dilation, sometimes up to 3 or 4 centimeters, weeks before active labor begins. This early dilation is part of the body’s gradual process of readying itself for the upcoming delivery.
Cervical effacement often accompanies dilation, with the cervix becoming softer, shorter, and thinner. For those who have given birth before, the cervix might dilate earlier than for first-time parents. The onset and progression of effacement and dilation vary significantly, making it difficult to predict labor timing based solely on these measurements. A healthcare provider typically assesses these changes through a pelvic examination as pregnancy nears full term.
Other Signs of Approaching Labor
Beyond cervical changes, other physical signs indicate the body is preparing for labor. One sign is “lightening,” where the baby drops lower into the pelvis. This can increase pressure on the bladder and lead to more frequent urination. This change in the baby’s position might also make breathing feel easier as there is less pressure on the diaphragm.
Braxton Hicks contractions, often described as “practice” contractions, are another common sign. These contractions are irregular, do not increase in intensity or frequency, and usually subside with a change in activity or hydration. While they prepare the uterus for labor, Braxton Hicks contractions do not cause cervical dilation.
The loss of the mucus plug, a thick collection of discharge that seals the cervix, also signals approaching labor. This plug may appear clear, pink, or blood-tinged and can be lost days or even weeks before labor begins, or sometimes not until active labor itself. Increased vaginal discharge (leukorrhea) is also common in the weeks leading up to labor.
When to Contact Your Healthcare Provider
While these signs indicate labor preparation, some symptoms warrant immediate contact with a healthcare provider. If regular, painful contractions occur, especially if they become stronger, longer, and closer together, seek medical advice. True labor contractions will not ease with changes in position or activity. If your water breaks, whether as a gush or a trickle of fluid, contact your provider immediately, noting the time and color. Green or brown fluid is particularly important to note, as it could indicate meconium (the baby’s first stool).
Significant vaginal bleeding, especially bright red blood, also requires immediate medical attention. While a small amount of blood-tinged mucus is normal with mucus plug loss, heavy bleeding is concerning. Report any decrease in fetal movement or change from the baby’s usual pattern without delay. These symptoms require prompt evaluation to ensure the well-being of both the pregnant individual and the baby.