A cervical exam is when your doctor or midwife inserts two fingers into your vagina to assess your cervix. This can be done at a prenatal visit if you are having contractions or are close to your due date, or when you are in labor to see how your labor is progressing. But what exactly are they measuring when they’re doing this?
1. Dilation—This refers to how open your cervix is. A closed cervix is just that—closed—while a fully dilated cervix is 10 centimeters open! You usually need to be fully dilated in order to start pushing, but if you are very preterm you may be able to deliver with a cervix that is not completely open. It is important to keep in mind that this single measurement cannot really tell your doctor or midwife if you are in active labor. For example, some women can be 3 or 4 centimeters dilated a week or more before they deliver. Therefore, it is important to take all the other measurements into account as well as seeing if there is any change over time to assess if you are really in labor or not.
2. Effacement—This refers to how thinned down your cervix is. With the typical cervix being 3 to 4 centimeters in length, your provider will usually report this measurement as a percentage. For example, if your cervix is not at all thinned out, you are 0 percent effaced. On the other hand, a completely thinned cervix is 100 percent effaced. First-time moms tend to efface first and then dilate, while the opposite is true for women who have given birth before. But this generalization does not always hold true for everyone.
3. Station—This measurement tells you where your baby’s head is in relation to your ischial spines, or small bony parts that are part of your pelvic bones. If you baby is at the level of the ischial spines, he or she is at 0 station. This measurement is on a scale from -5 (high above the spines and not engaged in the pelvis) to +5 (the head is crowning and visible at the vaginal opening).
4. Cervical position—Your cervical position can be reported as posterior (very far back), mid-position, or anterior (right in front). In general, a posterior cervix is one that is not yet in active labor. If your cervix is very posterior, lying flat for the exam or propping pillows under your hips can help your doctor or midwife reach it to examine it.
5. Cervical consistency—A cervix that is not yet in labor is usually quite firm, while a “ripe” cervix that is preparing for labor is softer. Cervical softening needs to happen before any dilation or effacement begins.
6. Fetal position—If your provider is unable to tell which way your baby is positioned by feeling your abdomen, sometimes a cervical exam can help clarify if your baby is head down or breech. When your cervix is more dilated, the exact position of your baby’s head can also be felt (facing down, up, or to the side).
Reviewed by Dr. Jen Lincoln, April 2020
- A cervical exam is when your obstetric provider uses two fingers to measure your cervix.
- This can help assess if your cervix is preparing for labor or to see how your labor is progressing.
- No specific number for dilation is considered definitive when it comes to active labor.