Tarleton State University
Diana Kunce-Collins RNC-MNN
January 24, 2015
Labor and Delivery Pathophysiology
Definition: The physiologic process during which the fetus, membranes, umbilical cord, and placenta are expelled from the uterus. (Medscape 2014)
Etiology: According to research, the exact cause of labor has yet to be discovered. Labor normally starts when the fetus is mature enough to adjust easily to extra uterine life but before it grows so large that vaginal birth is impossible. Natural labor begins when forces favoring continuation of pregnancy are offset by forces favoring its end. (Murray 2014)
Pathogenesis: There are signs a woman will experience when she is getting close to labor. She will experience an increase in Braxton Hicks contractions, descent of the fetus towards the pelvis, increased vaginal secretions, cervical ripening, bloody show, an increase in weight loss, and a sudden increase in energy. During the first stage of labor, cervical effacement and dilation occur. There are three phases of the first stage; latent, active, and transition. The active phase begins when the cervix of a nullipara dilates 1.2 centimeters per hour and a multipara dilates about 1.5 centimeters an hour. (Murray 2014) The latent phase may be long and lasts through the first three centimeters of dilation. In preparation for rapid changes in labor, cervical effacement and fetal position change. Frequency, duration, and intensity of contractions will gradually increase until they are five minutes apart. By the end of the latent phase, durations of the contractions will increase to 30 to 40 seconds and the intensity is mild. When the cervix dilates from four to seven centimeters and at a more rapid rate, the patient is entering the active phase. The fetus descends to the pelvis, effacement of the cervix is complete, and internal rotation begins. Reaching their peak, contractions now
References: McKinney, E., & Murray, S. (2014). Foundations of Maternal – Newborn and Women’s Health Nursing, (6th Ed). St. Louis: Elsevier.