BACKGROUND AND PURPOSE: 

• Risk factors for postterm pregnancy include obesity, nulliparity and maternal age >30  
• Postterm pregnancy is associated with risk, especially to the fetus/newborn, while there is potential for adverse outcomes related to interventions associated with induction of labor  
• Middleton et al. (Cochrane Reviews, 2018) sought to determine whether a policy of labor induction at or beyond term could improve pregnancy outcomes for infant and mother

METHODS: 

• Database search of randomized controlled trials (RCTs)  
• Participants: Low-risk pregnant women at or beyond term enrolled in trials comparing induction to expectant management  
• Policies differed with respect to  
  • Gestational age used in the policy | Actual method of labor induction | Expectant management protocols (intensity of fetal monitoring)  
• Majority of trials (75% of participants) adopted a policy of induction at ≥41 weeks gestation 
• Induction protocols ranged from from 37 to >42 weeks induction policies  
  • For purposes of this study, gestational ages were collapsed in to 3 groups: (1) Induced at <41 weeks; (2) Induced ≥41 weeks; (3) inductions spanning 37 to 42 weeks  
• Primary outcome: Perinatal death (intrauterine plus neonatal)  
• Secondary outcomes 
  • Adverse maternal and fetal outcomes | Mode of delivery | Health services use (length of stay and labor)

RESULTS: 

• 30 RCTs were included in this review (moderate risk for bias) 
• Compared with expectant management, labor induction was associated with  
  • Fewer all-cause perinatal deaths: Risk ratio (RR) 0.33; 95% CI, 0.14 to 0.78 (moderate-quality evidence) 
  • Fewer stillbirths: RR 0.33; 95% CI, 0.11 to 0.96 (moderate-quality evidence) 
  • Fewer C-sections: RR 0.92; 95% CI, 0.85 to 0.99 (moderate-quality evidence) 
  • Increase in operative vaginal births: RR 1.07; 95% CI, 0.99 to 1.16 (moderate-quality evidence) 
  • Fewer NICU admissions: RR 0.88; 95% CI, 0.77 to 1.01 (moderate-quality evidence)  
  • Fewer babies had Apgar scores <7 at 5 minutes: RR 0.70; 95% CI, 0.50 to 0.98 (moderate-quality evidence) 
• There was no differences between groups regardless of gestational age for  
  • Perineal trauma | Postpartum hemorrhage | length of maternal hospital stay | Neonatal trauma
• In cervical state or timing of induction (<41 weeks vs ≥41 weeks) there were no differences in perinatal death, stillbirth, NICU admission, cesarean section or perineal trauma
  • More operative deliveries in <41 week group  

CONCLUSION: 

• Adopting a policy of labor induction lead to better pregnancy outcomes for mother and child, including fewer perinatal deaths, fewer C-sections, more operative vaginal births, and fewer NICU visits 
• According to the authors,

A policy of labour induction was associated with fewer perinatal deaths (with two perinatal deaths in the labour induction policy group compared with 16 perinatal deaths in the expectant management group) (moderate-quality evidence). When restricted to a policy of induction at later gestational ages (> 41 weeks), there were two and 13 perinatal deaths, respectively.

Learn More – Primary Sources:  

Induction of labor for improving birth outcomes for women at or beyond term

ACOG Committee Opinion 579: Definition of Term Pregnancy  

Related ObG Topics:

A New Predictive Model for Successful Induction of Labor

Labor induction and an unripe cervix: does it result in more C-sections?

Cochrane Review 2017: Outpatient Cervical Ripening and Labor Induction