While there is no perfect formula for determining when labor will start, your doctor can measure how close you are at your weekly appointments. These measurements and observations include:
While there is no perfect formula for determining when labor will start, your doctor can measure how close you are at your weekly appointments. These measurements and observations include:
Presentation: This describes the part of your baby’s body that is farthest down in your pelvis. Ideally, it’s the head.
Station: This refers to how far your baby's head has moved into your pelvic cavity. Each station is 1 centimeter.
High in your pelvic cavity, your baby is at -5 station.
At 0 station, he’s midway through the pelvis and is engaged in your pelvis. For a first pregnancy, this is most commonly the position at the beginning of labor.
Once actual labor begins, your baby's head continues through the pelvis to +1, +2, and +3 stations.
At +5 station, your baby's head is crowning (appearing) during birth.
Dilation: This refers to how much your cervix has opened. It is measured in centimeters. Some women begin to dilate several weeks before labor. At 10 centimeters, you are ready to start pushing out your baby.
Effacement: This refers to how much your cervix has thinned in preparation for birth, and is often measured by percentage. If this is your first pregnancy, effacement usually begins before dilation. At 100% effaced, you are ready to deliver your baby.
You might experience some or all of these symptoms as labor begins:
- Cervical changes, including effacement, softening, and dilation
- Water breaking (though the percentage of women whose water breaks "on its own" is small)
- Diarrhea
- Nausea