As labor nears, the fetus's head drops down into the pelvis and pushes against the cervix. The cervix begins to thin (efface) and open (dilate), sometimes over a few weeks.
Last Revised: November 2, 2011
Author: Healthwise Staff
Medical Review: Sarah Marshall, MD - Family Medicine & Kirtly Jones, MD - Obstetrics and Gynecology
To learn more visit Healthwise.org