Whether you are a new mom or a well seasoned one, the last thing that you want to hear at any stage in your pregnancy is the word “negative.” It immediately fills your head with the worst possible ideas, causing you undue stress. Late in pregnancy, a midwife or doctor may start to check your cervix to see about effacement, dilation and station (although many no longer do, due to the inaccuracy of these measurements in a normal pregnancy). If you hear things like “1 centimeter, 25%, -2” and that negative number makes you worry, don’t. First, check out this guide on effacement, dilation and station so that you are better informed at your next appointment.
Measured in percentages.
Before a woman becomes pregnant and most of the way into her third trimester, the cervix is very long and thick. When labor draws near, the cervix begins to shorten and become thinner. The process of this change in the cervix is called effacement.
When your doctor or midwife is measuring your cervix, they are typically going to do so by using percentages. When you are being examined, your care provider will give you the information in the form of a percentage that ranges anywhere from 0%, which means you are not effaced at all, to 100%, meaning that you are completely effaced and thin. Whenever your cervix has become totally effaced, it becomes one with the uterine wall, allowing your mucus plug to be released and the baby to pass through.
Measured in centimeters.
Many women believe there is such a thing as “negative dilation,” when in reality, there is not. In truth, instead of a negative dilation, there is a negative station, but we will get to that in a moment. With dilation, your cervix should remain closed and tight without dilation until your third trimester. This helps protect the child from bacteria. When it is almost time to deliver the child, your cervix will open for the baby to pass through. This will be measured in centimeters. Most of your pregnancy will have your cervix at 0% and will open to 10% when the time comes.
Negative and positive relation to the pelvic bone (ischial spine).
Station is where that scary negative number could possibly come into play. It is not a bad thing, though–not at all! When your doctor or midwife is telling you your baby’s station, they are referring to the proximity your baby’s head has come to your pelvis. If your baby has dropped but has not yet settled into your pelvis to start their descent, the station will be measured in centimeters as a negative station. The negative measurements range from -3 to -1. Once the baby has gotten settled in your pelvis, but before the descent to the birth canal, it will be referred to as a 0 station. When the baby begins to travel toward the cervix, it will be referred to as a positive station with a number ranging from 1 to 3. It is during this time that you will likely begin to notice the increase of pain and pressure in your vaginal area and pelvic bone.
It is here that many women get confused and think that they are told they are experiencing negative dilation. It is a common misconception, and doctors and midwives are always referring to the station of the child instead. Now that you are informed about the measurements they will take, you can head to your next checkup armed with knowledge so that you can get rid of the anxiety surrounding the word “negative.” If you find you still have questions, ask your care provider and they will be happy to explain what you are not sure about.