Date Published: April 25, 2018
Publisher: Public Library of Science
Author(s): Rachel G. Sinkey, Jasmin Lacevic, Tea Reljic, Iztok Hozo, Kelly S. Gibson, Anthony O. Odibo, Benjamin Djulbegovic, Charles J. Lockwood, Roger C. Young.
Optimal management of pregnancies at 39 weeks gestational age is unknown. Therefore, we sought to perform a comparative effectiveness analysis of elective induction of labor (eIOL) at 39 weeks among nulliparous women with non-anomalous singleton, vertex fetuses as compared to expectant management (EM) which included IOL for medical or obstetric indications or at 41 weeks in undelivered mothers.
A Monte Carlo micro-simulation model was constructed modeling two mutually exclusive health states: eIOL at 39 weeks, or EM with IOL for standard medical or obstetrical indications or at 41 weeks if undelivered. Health state distribution probabilities included maternal and perinatal outcomes and were informed by a review of the literature and data derived from the Consortium of Safe Labor. Analyses investigating preferences for maternal versus infant health were performed using weighted utilities. Primary outcome was determining which management strategy posed less maternal and neonatal risk. Secondary outcomes were rates of cesarean deliveries, maternal morbidity and mortality, stillbirth, neonatal morbidity and mortality, and preferences regarding the importance of maternal and perinatal health.
A management strategy of eIOL at 39 weeks resulted in less maternal and neonatal risk as compared to EM with IOL at 41 weeks among undelivered patients. Cesarean section rates were higher in the EM arm (35.9% versus 13.9%, p<0.01). When analysis was performed only on patients with an unfavorable cervix, 39 week eIOL still resulted in fewer cesarean deliveries as compared to EM (8.0% versus 26.1%, p<0.01). There was no statistical difference in maternal mortality (eIOL 0% versus EM 0.01%, p = 0.32) but there was an increase in maternal morbidity among the EM arm (21.2% versus 16.5, p<0.01). There were more stillbirths (0.13% versus 0%, p<0.0003), neonatal deaths (0.25% versus 0.12%, p< 0.03), and neonatal morbidity (12.1% versus 9.4%, p<0.01) in the EM arm as compared to the eIOL arm. Preference modeling revealed that 39 week eIOL was favored over EM. Mathematical modeling revealed that eIOL at 39 weeks resulted in lower population risks as compared to EM with induction of labor at 41 weeks. Specifically, eIOL at 39 weeks resulted in a lower cesarean section rate, lower rates of maternal morbidity, fewer stillbirths and neonatal deaths, and lower rates of neonatal morbidity.
Timing of delivery is a vital component of a healthy pregnancy. An increase in morbidity and mortality exists on both ends of the gestational age at delivery spectrum. On one hand, preterm birth is the leading cause of neonatal morbidity and mortality in the United States and is associated with substantial societal and healthcare costs.[1, 2] On the other, late-term and post-term pregnancies are also associated with increased maternal, fetal and neonatal risks. Because of these risks, the American College of Obstetricians and Gynecologists (ACOG) states that a provider may consider induction of labor between 41 0/7 and 41 6/7 weeks gestational age and recommends induction of labor after 42 0/7 weeks gestational age.
Using a decision analytic model informed by contemporaneous literature, we found that elective induction of labor among uncomplicated nulliparous women with vertex presenting singleton fetuses resulted in less maternal and neonatal risk as compared to expectant management with induction of labor for medical or obstetrical indications or by 41 weeks if undelivered. The cesarean section rate was significantly higher in the expectant management cohort as compared to elective induction of labor as shown in Fig 2: 35.9% versus 13.9%, p<0.01. When patients with an unfavorable cervix were analyzed, 39 week eIOL still resulted in fewer cesarean deliveries as compared to EM (8.0% versus 26.1%, p<0.01). Using Monte Carlo microsimulation methodology, we found that, among uncomplicated, nulliparous, non-anomalous, singleton, vertex pregnancies, elective induction of labor at 39 weeks resulted in less maternal and neonatal risk as compared to expectant management with subsequent induction of labor by 41 weeks gestation. Specifically, irrespective of cervical examination, the 39 week elective induction cohort experienced fewer cesarean deliveries, lower rates of maternal morbidity, fewer stillbirths and neonatal deaths, and less neonatal morbidity than mothers expectantly managed until 41 weeks. Source: http://doi.org/10.1371/journal.pone.0193169