Effacement, Dilation and Station
Around your 37th week of pregnancy your doctor or midwife will begin checking your cervix for effacement, dilation and station. Many first time as well as seasoned moms aren’t sure what this means. If reports of “one centimeter, 25%, -2” leave you feeling dazed and confused, this explanation of effacement, dilation and station will keep you in the know at your next check up.
Prior to pregnancy and into 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.
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% (not effaced at all) to 100% (completely effaced and thin). When your cervix is completely effaced it becomes part of the uterine wall and your mucus plug is released, allowing the baby to pass through.
Your cervix should stay tight and closed with no dilation until late into your third trimester. This keeps bacteria away from your precious cargo. As you get closer to delivery the mouth of the cervix opens and widens, allowing your baby to pass through. This is measured in centimeters. For most of your pregnancy it should be 0 centimeters, opening to 10 centimeters when it’s time deliver. As the cervix dilates, some people describe cramping and pressure, similar to what you would feel during menstruation. Yay for labor pains!
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.
When your provider tells you about your baby’s station, she is referring to how far down your baby’s head has come into your pelvis. If your baby has dropped, but has not yet settled into your pelvis to begin his or her 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. Yay again for labor!
It’s 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 but not relay this information unless you ask. If you aren’t told, or if you are not offered a cervical check, don’t be shy … ask away!
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