Why some doctors offer induction at 39 weeks

What does the evidence say about elective induction at 39 weeks during pregnancy?

1. The ARRIVE randomized trial assigned low-risk first-time mothers to induction at 39 0/7 to 39 4/7 weeks or expectant management, with delivery initiated no later than 42 2/7 weeks in the expectant group. 1
2. In ARRIVE, cesarean delivery occurred in 18.6% of the induction group and 22.2% of the expectant-management group. 1
3. The ARRIVE primary composite of perinatal death or severe neonatal complications occurred in 4.3% of induction births and 5.4% of expectant-management births, a difference the trial did not classify as statistically significant. 2
4. A large observational study found an increase in 39-week induction after ARRIVE publication and a small decrease in cesarean delivery compared with the expected trend. 3
5. A prospective observational study of 304 nulliparous singleton pregnancies induced at 39 weeks reported its own cesarean, intensive-care, and newborn outcomes and cautioned that its findings did not reproduce the ARRIVE cesarean result. 4

Is elective induction at 39 weeks safe in each trimester?

• First trimester. The ARRIVE trial concerns the end of pregnancy, so a first-trimester discussion is mainly about learning what low-risk, first-birth eligibility means and how your preferences will be revisited later.
• Second trimester. During the second trimester, ask how your hospital defines low risk, how induction is started, and what might change the plan. The ARRIVE findings came from a specific population and do not automatically apply to every pregnancy.
• Third trimester. At 39 weeks, elective induction is a shared decision for eligible patients. The trial found lower cesarean frequency in low-risk first-time mothers, while expectant management remained a reasonable option in the trial's interpretation.