Introduction: Professional bodies have published guidelines defining the length of the second stage of labor and when it is "prolonged", according to parity and epidural anesthesia administration. Recently these guidelines have been extended, aiming to reduce rates of unplanned cesarean deliveries.
Aims: To examine the risk factors and outcomes of a prolonged second stage of labor, in order to understand its causes and implications for mothers and neonates, including the delivery mode.
Methods: A retrospective study based on 26,476 electronic medical records of deliveries to primiparous mothers of a term singleton fetus, at Hadassah Medical Center, between 2003 and 2015.
Results: A prolonged second stage of labor was recorded in 3,225 (12.2%) of mothers (i.e. exceeding 2 hours without epidural anesthesia and 3 hours with it). Epidural anesthesia, persistent occiput posterior, and head circumference or birth weight above the 90th percentile, increased the risk of the prolonged second stage. The risk of unplanned cesarean delivery rose significantly before the 2- or 3-hour cut-off defining a prolonged second stage. Risks of maternal and neonatal complications included: grade III-IV perineal tear, maternal hemorrhage, 5-minute Apgar≤7, umbilical artery pH<7.1, neonatal intensive care admission were also increased.
Conclusions: Epidural anesthesia and fetal parameters increased the risk of prolonged second stage; risks of maternal and fetal complications were also increased. The risk of interventional delivery increased significantly well before the defined cut-off.
Discussion: Prolongation of the second stage of labor is a common pathway of many obstetric outcomes. Obstetric management should be based on considerations of individual maternal and neonatal well-being, rather than administrative goals. While reducing cesarean rates is an important goal, attempts to achieve this by prolonging the second stage of labor exposes mothers and neonates to excess risk of cesarean and vacuum delivery as well as obstetric and neonatal complications.