If you are experiencing a medical emergency please dial 911 immediately
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
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