In most pregnancies, at about 37 weeks, your doctor or midwife will begin checking your cervix for effacement, dilation and station. She will then report back to you the results. For first time moms this can be confusing. If you don’t know what effacement, dilation and station are, then when your provider reports that you are, “One centimeter, 25%, -2,” you may feel very confused. Below are explanations of each stage of your body’s preparation for delivering your baby.

Effacement
Prior to pregnancy and in the first and second trimester, as well as much of the third trimester, your cervix is long and thick. As labor nears it begins to shorten and thin out. This action is referred to as effacement. As your cervix begins to efface, the plug keeping the entrance to the uterus sealed is released. This is called your mucus plug and it may contain some blood.

Effacement is generally measured in percentages by doctors and midwives. When you have an exam your provider will tell you that it is anywhere from 0% to 100% which means not effaced at all to completely effaced and thin. When it is completely effaced it becomes a part of the uterine wall, allowing the baby to pass through.

Dilation
Until you are late in your third trimester, your cervix should stay tight and closed with no dilation. Dilation is the process of the mouth of the cervix opening and widening, which allows your baby to pass through. This is measured in centimeters. For most of your pregnancy it should be 0 centimeters. In order to deliver your baby your cervix needs to stretch open to 10 centimeters. As the cervix dilates, some people describe cramping and pressure, similar to what you would feel during menstruation.

If you begin dilating in the second trimester or at a rapid rate before the last month of your pregnancy it can be a sign of premature labor. If this is the case your doctor or midwife will advise you on what to do next.

Station
When your provider tells you about your baby’s station, she is referring to how far down his head has come into your pelvis. If your baby has dropped, but has not yet settled into your pelvis to begin his decent, it is measured in centimeters as a negative station. This negative measurement goes from -3 to -1. Once your baby has settled into your pelvis, but before he starts his descent to the birth canal, it is referred to as a zero (0) station. Once your baby starts heading towards the cervix, it is referred to as a positive station from 1 to 3. During this time it is likely that you will feel an increase of pressure and pain in your pelvic bone and vaginal area.

It is good for a mom-to-be to know where her baby is positioned and how her body is cooperating in the weeks leading up to delivery. Some doctors will check you but not relay any information to you unless you ask. If you want to know and are not told, or if you are not offered a cervical check, ask your provider to tell you or to check you so that you are aware