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Evevident
Original paper
2018NEJMOB/GYN

ARRIVE

Labor Induction versus Expectant Management in Low-Risk Nulliparous Women

RCTObstetrics / delivery

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Overview

Elective induction at 39 weeks in low-risk nulliparous patients did not worsen perinatal outcomes and reduced cesarean delivery.

Clinical takeaway

ARRIVE supports offering elective 39-week induction to low-risk nulliparous patients when resources and patient preferences align.

Key result

The perinatal composite was not significantly different (4.3% vs 5.4%), but cesarean delivery was lower with induction (18.6% vs 22.2%).

Practice impact

Elective 39-week induction is a reasonable option for low-risk nulliparous patients, not an automatic cesarean-risk increase.

Evidence

Study design

Randomized controlled trial.

Enrollment

6,106

Follow-up

Through delivery and the immediate postnatal period.

Geography

United States

Clinical question

Does elective induction at 39 weeks improve or worsen outcomes compared with expectant management in low-risk nulliparous pregnancy?

Population

  • Low-risk nulliparous pregnant patients with a singleton vertex gestation.

Intervention

Elective induction of labor at 39 0/7 to 39 4/7 weeks.

Comparator

Expectant management (awaiting spontaneous labor, delivery by 42 2/7 weeks).

Primary outcome

Composite of perinatal death or serious neonatal complications; cesarean delivery was the principal secondary outcome.

Elective 39-week induction did not significantly change the perinatal composite but reduced cesarean delivery and hypertensive disorders of pregnancy.

Relative risk / 0.8 / CI 95% CI 0.64-1.00 / p=not significant

Key results

  • Primary perinatal composite: 4.3% with induction vs 5.4% with expectant management; RR 0.80 (95% CI 0.64-1.00), not statistically significant.
  • Cesarean delivery: 18.6% with induction vs 22.2% with expectant management; RR 0.84 (95% CI 0.76-0.93; p<0.001).
  • Hypertensive disorders of pregnancy were lower with induction (9.1% vs 14.1%; RR 0.64).

Harms

  • Elective induction did not increase adverse perinatal outcomes or operative delivery.
  • Induction lengthened time on the labor-and-delivery unit.

Clinical Use

When to cite

  • When counseling a low-risk nulliparous patient about elective induction at 39 weeks and its effect on cesarean delivery risk.

Practice impact

  • Elective 39-week induction is a reasonable option for low-risk nulliparous patients, not an automatic cesarean-risk increase.

Applicability

  • Most applicable to low-risk nulliparous pregnant patients with singleton vertex gestation.

Limitations

  • Requires adequate obstetric resources and shared decision-making; enrolled patients willing to be randomized.
  • Results apply to low-risk nulliparous singleton vertex pregnancies, not higher-risk populations.
  • Real-world generalizability depends on induction being conducted per protocol (allowing adequate time).

Common misinterpretations

  • Elective induction at 39 weeks did not increase cesarean delivery; it modestly reduced it, contradicting older teaching.
  • The primary perinatal composite was neutral (not significant), so induction is offered as reasonable, not mandated.

Citation

Grobman WA, Rice MM, Reddy UM, et al. Labor Induction versus Expectant Management in Low-Risk Nulliparous Women. N Engl J Med. 2018;379(6):513-523. doi:10.1056/NEJMoa1800566

Induction of labor at 39 weeks in low-risk nulliparous women did not result in a significantly lower frequency of a composite adverse perinatal outcome, but it did result in a significantly lower frequency of cesarean delivery.