he normal duration of labor may be clouded by the many clinical variables that afect the conduct of labor in modern obstetrical units. Kilpatrick and Laros (1989) reported that the mean length of irst-and second-stage labor was approximately 9 hours in nulliparas without regional analgesia, and that the 95th percentile upper limit was 18.5 hours. Corresponding times for multiparas were a mean of 6 hours and a 95th percentile maximum of 13.5 hours. These authors defined labor onset as the time when a woman recalled regular, painful contractions every 3 to 5 minutes that led to cervical change.
Spontaneous labor was analyzed in nearly 25,000 women delivered at term at Parkland Hospital in the early 1990s. Almost 80 percent of women were admitted with a cervical dilation of 5 cm or less. Parity-nulliparous versus multiparous-and cervical dilation at admission were significant determinants of the length of spontaneous labor. The median time from admission to spontaneous delivery for all parturients was 3.5 hours, and 95 percent of all women delivered within 10.1 hours. These results suggest that normal human labor is relatively short.
• Summary of Normal Labor
Labor is characterized by brevity and considerable biological variation. Active labor can be reliably diagnosed when cervical dilation is :3 cm in the presence of uterine contractions. Once this cervical dilation threshold is reached, normal progression to delivery can be expected, depending on parity, in the ensuing 4 to 6 hours. Anticipated progress during a 1-to 3-hour second stage is monitored to ensure fetal safety. Finally, most women in spontaneous labor, regardless of parity, if left unaided, will deliver within approximately 10 hours after admission for spontaneous labor. Insuicient uterine activity is a common and correctable cause of abnormal labor progress. Thereore, when the length of otherwise normal labor exceeds the expected norm, interventions other than cesarean delivery-or example, oxytocin administration-must be irst considere.
The ideal management of labor and delivery requires two potentially opposing viewpoints on the part of clinicians. First, birthing should be recognized as a normal physiological process that most women experience without complications. Second, intrapartum complications, often arising quickly and unexpectedly, should be anticipated. Thus, clinicians must simultaneously make every woman and her supporters feel comfortable, yet ensure safety for the mother and newborn if complications suddenly develop. he American Academy of Pediatrics and the American College of Obstetricians and Gynecologists (2017) have collaborated in the development of Guidelines or Perinatal Care. These provide detailed information on the appropriate content of intrapartum care, including both personnel and facility requirements (Table 22-2).
Labor and delivery outside the hospital is elected by some parturients. This option and its risks and benefits are discussed in Chapter 27 (p. 524).
Congress enacted EMT ALA in 1986 to ensure public access to emergency services regardless of the ability to pay. All Medicare-participating hospitals with emergency services must provide an appropriate screening examination for any pregnant woman experiencing contractions and presenting to the emergency department for evaluation.
The deinition of an emergency condition makes specific reference to a pregnant woman who is having contractions. Labor is defined as "the process of childbirth beginning with the latent phase of labor continuing through delivery of the placenta. A woman experiencing contractions is in true labor unless a physician certifies that after a reasonable time of observation the woman is in false labor." A woman in true labor is considered "unstable" for interhospital transfer purposes until the newborn and placenta are delivered. A stable woman may, however, be transferred at the direction of the patient or by a physician who certifies that the benefits of treatment at another facility outweigh the transfer risks. Physicians and hospitals violating these federal requirements are subject to civil penalties and termination from participation in the Medicare program.
• Identification of Labor