During labour the uterine muscles contract and shorten, opening and pulling up the cervix into the lower segment making way for your baby to pass through, as well as propelling your baby forward to be born.
Image 1-07 shows the uterus and baby towards the end of pregnancy.
Updated November 2007
Information sources
Stables D. and Rankin J. Physiology in Childbearing with Anatomy and Related Biosciences. 2004, Bailliere Tindall, Edinburgh.