TY - CHAP M1 - Book, Section TI - Physiology of Labor A1 - Cunningham, F. Gary A1 - Leveno, Kenneth J. A1 - Dashe, Jodi S. A1 - Hoffman, Barbara L. A1 - Spong, Catherine Y. A1 - Casey, Brian M. PY - 2022 T2 - Williams Obstetrics, 26e AB - Labor is characterized by forceful and painful uterine contractions that effect cervical dilation and cause the fetus to descend through the birth canal. However, extensive preparations take place in both the uterus and cervix long before this. During the first 36 to 38 weeks of normal gestation, the myometrium is in a preparatory yet unresponsive state. Concurrently, the cervix begins an early stage of remodeling yet maintains structural integrity. Following uterine quiescence, a transitional phase begins during which myometrial unresponsiveness is suspended and the cervix undergoes ripening, effacement, and loss of structural cohesion. SN - PB - McGraw Hill CY - New York, NY Y2 - 2024/03/29 UR - obgyn.mhmedical.com/content.aspx?aid=1197681475 ER -