Opening of the cervix

Another sign of early labor is the cervix beginning to open. That's called dilation. Dilation is measured in centimeters from zero to 10. At zero there's no dilation. At 10 centimeters, the cervix is fully dilated.

At first, these cervical changes can be very slow. Once you're in active labor — when the cervix is open 6 centimeters or more — expect to dilate more quickly.