ARRIVE trial: elective IOL at 39 weeks

Question 1

ARRIVE trial:

When was this published and in what journal?

Answer 1

Published in 2019 in NEJM

Question 2

ARRIVE trial:

What was the hypothesis of this trial?

Answer 2

Elective IOL at 39 weeks will result in a lower risk of composite outcome of perinatal death or severe neonatal complications than expectant management in low-risk nulliparous women.

Question 3

ARRIVE trial:

What type of study was this?

Answer 3

Multicentre randomised controlled parallel-group, unmasked trial

Question 4

ARRIVE trial:

What was the inclusion criteria?

Answer 4

Inclusion criteria:

• GA 34+0 to 38+6 weeks
• Live singleton pregnancy
• Cephalic
• No contraindications to vaginal delivery
• No CS planned.
• Certainty of gestation.

Question 5

ARRIVE trial:

What was the exclusion criteria?

Answer 5

• Indication for delivery.
• In labour
• Premature rupture of membranes
• Vaginal bleeding

Question 6

ARRIVE trial:

How many women were in the trial?

How many were randomised to IOL group?

How many were randomised to expectant management group?

Answer 6

Study population: 6106

Treatment groups:

• IOL grp 3062
• Expectant grp 3044

Question 7

ARRIVE trial:

Describe the method of this study:

Answer 7

• Assessed again at 38+0 to 38+6 to ensure no new indication for delivery.
• 72 hrs before to 24 hrs after randomisation, cervical exam to determine modified Bishop score.
• IOL grp: IOL at 39+0 to 39+4.
• Expectant grp: forego IOL before 40+5 and to have IOL started no later than 42+2.
• No specific IOL protocol.

Question 8

ARRIVE trial:

Outline the primary and secondary outcomes of this study and relevant findings

Answer 8

1◦ outcomes:

• Composite of perinatal death or severe neonatal complications:
  
  • 4.3% IOL grp vs 5.4% expectant grp, not statistically significant.

2◦ outcomes:

• Caesarean section delivery:
  
  • Significantly lower CS in IOL grp 18.6% vs 22.2% expectant grp.
• Neonatal outcomes: BW, morbidity:
  
  • Neonates in IOL grp had shorter duration of respiratory support and total hospital stays.
• Maternal outcomes: PET/HTN, instrumental, OASIS, chorioamnionitis, VTE etc:
  
  • Significantly less likely to have HTN disorders of pregnancy 9.1% IOL grp vs 14% expectant grp.
• Subgroup analyses showed no differences in results.

Question 9

ARRIVE trial:

What were the conclusions from the trial?

Answer 9

IOL at 39 weeks in low-risk nulliparous women did not result in a significantly lower frequency of composite adverse perinatal outcome but did result in significantly lower frequency of CS.

Question 10

ARRIVE trial:

What were some strengths and weaknesses of the trial?

Answer 10

Strengths:

• Larger than previous randomised trials comparing similar things.

Weaknesses:

• Masking allocations not feasible; ascertainment bias is possible.
• Despite its size, trial was not powered to detect differences in infrequent outcomes.
• Unclear if results are broadly generalisable but inclusion of university and community hospitals and variety of obstetric providers and multiple IOL protocols probably makes it generalisable to similar centres.

Question 11

ARRIVE trial:

What were some discussion points for this trial?

Answer 11

• IOL may be associated with a 36% lower risk than expectant mgmt.
• NNT (IOL) to avoid 1 CS: 28.
• Cost-effectiveness not evaluated; elective IOL at 39 weeks may not be feasible cost-wise.