he American College of Obstetricians and Gynecologists (2016) does not endorse this once widespread practice. Occasional exceptions might include logistical and other reasons such as a risk of rapid labor, a woman who lives a long distance from the hospital, or psychosocial indications. Because of the greater risks for adverse maternal outcomes, we are also of the opinion that routine elective induction at term is not justified. Elective delivery before 39 completed weeks is also associated with signiicant adverse neonatal morbidity (Chiossi, 2013; Clark, 2009; Salemi, 2016; Tita, 2009). If elective induction is considered at term, inherent risks must be discussed, informed consent obtained, and guidelines followed as promulgated by the American College of Obstetricians and Gynecologists (2016), which are detailed in Chapter 31 (p. 597).
Guidelines to discourage elective inductions have been described by Fisch (2009) and Oshiro (20l3) and their associates. Both groups reported signiicant declines in elective delivery rates following guideline initiation. In 201i1, the Texas Medicaid program began to deny payment for elective induction prior to 39 weeks' gestation. his resulted in a 14-percent drop in such early-term deliveries and a rise in birthweights (Dahlen, 2017). A program in Oregon also reduced early-term deliveries, but maternal and fetal outcomes were not improved (Snowden, 2016).
Several factors afect the ability of labor induction to achieve vaginal delivery. Favorable factors include younger age, multiparity, body mass index (BMI) <30, favorable cervix, and birthweight <3500 g (Gibson, 2015; Roland, 2017; Sievert, 2017). In many cases, the uterus is simply poorly prepared for labor. One example is an "unripe cervix." Indeed, investigators with the Consortium on Sae Labor reported that elective induction resulted in vaginal delivery in 97 percent of multiparas and 76 percent of nulliparas, but that induction was more often successful with a ripe cervix (Laughon, 2012).
he greater cesarean delivery risk associated with induction is likely also strongly influenced by the induction attempt duration, especially with an unfavorable cervix (Spong, 2012). In one study, labor duration to reach the active phase and to complete dilation was adversely afected by a higher BMI (Kominiarek, 2011). Similar indings were reported for women with diabetes (Hawkins, 2017). Simon and Grobman (2005) concluded that a latent phase as long as 18 hours allowed most women undergoing labor induction to achieve a vaginal delivery without a signiicantly increased risk of maternal or neonatal morbidity. Rouse and associates (2000) recommend a minimum of
Induction and Augmentation of Labor 505
TABLE 26-1 . Some Commonly Used Regimens for Preinduction Cervical Ripening and/or Labor Induction
Prostaglandin E2 Oinoprostone gel, Cervical 0.5 mg; repeat in 1. Shorter 1-0 times with oxytocin infusion 0.5 mg (Prepidil) 6 hr; permit 3 doses total than oxytocin alone
Oinoprostone insert, Posterior 10 mg 1. Insert has shorter 1-0 times than gel 10 mg (Cervidil) 2. 6-12 hr interval from last insert to oxytocin aOf-label use.
bTablets must be divided for 25-and 50-�g dose, but drug is evenly dispersed. EASI = extraamnionic saline infusion at 30-40 mUhr; 1-0 = induction-to-delivery.