Snapshot A 33-year-old G1P0 pregnant woman presents to the hospital at 41 weeks of gestation with contractions. She notes that she attended all of her prenatal appointments and had an uncomplicated pregnancy. She requests spinal-epidural anesthetics to alleviate her pain. After 5 hours of labor with adequate contractions (> 200 Montevideo units), her cervix is found to be dilated to 8cm with ruptured membranes. Introduction Overview abnormal labor occurs when the milestones of normal labor, in which uterine contractions result in progressive dilation and effacement of the cervix, are not reached Epidemiology 8-11% of deliveries are complicated by an abnormal first stage of labor ETIOLOGY Pathophysiology results of problems with the 3 P'S pelvis may be too small or narrow to allow infant's passage passenger large fetal size (macrosomia) abnormal position, presentation, or lie power frequency or intensity of contractions may be inadequate most common cause Presentation Symptoms prolonged contractions Physical exam delayed cervical dilation prolonged/protracted labor if cervical dilation is < 1.2 cm/hour (primipara) or 1.5 cm/hour (multipara) labor arrest if no cervical change in > 4 hours with adequate contractions (> 200 Montevideo units) or > 6 hours with inadequate contractions delayed cervical effacement Studies Labor curve plot the patient's labor progress (cervical dilation vs. duration in hours) Intrauterine pressure monitoring an intrauterine pressure catheter is used to measure the strength of uterine contractions Fetal heart tracing monitor for reassuring fetal heart rate patterns throughout the labor course Treatment Medical repositioning the patient use of a "peanut ball" may decrease the length of the first and second stages of labor oxytocin indications hypotonic contractions administer until contractions deemed adequate by frequency, intensity, and duration measures Surgical amniotomy indications may be used when patient has reached the active phase of labor not recommended in the latent phase of labor may increase risk of intrauterine infection or cord collapse operative vaginal delivery or cesarean delivery indications if conservative measures fail or if the fetal heart pattern is non-reassuring Complications Hyperstimulation of the uterus may result from prolonged medical induction of labor can result in several complications uterine rupture postpartum uterine atony postpartum hemorrhage Chorioamnionitis increased risk when rupture of membranes occurs for > 18 hours administer antibiotics Prognosis Likelihood of abnormal labor in subsequent pregnancies depends on the cause for abnormal labor i.e. if abnormal labor was due to small contours of the pelvis that were inadequate for a normal or small-sized infant, then the likelihood for recurrence is high