When is induction of labour recommended?

When is Induction of Labour Recommended?

Induction of labour is recommended for medical or obstetric indications where continuing pregnancy poses greater risks than delivery, including gestational hypertension/preeclampsia at ≥37 weeks, post-term pregnancy at ≥41 weeks, premature rupture of membranes, maternal diabetes with poor control, and Rh disease; additionally, elective induction at 39 weeks 0 days can be offered to low-risk nulliparous women to reduce cesarean delivery and hypertensive complications. 1, 2

Medical and Obstetric Indications for Induction

Hypertensive Disorders

• Induction should be advised for women with gestational hypertension or mild preeclampsia at 37 weeks' gestation to improve maternal outcomes 1
• Induction at 39 weeks in low-risk nulliparous women reduces hypertensive disorders from 14.1% to 9.1% (RR 0.64) 1

Post-Term Pregnancy

• Induction is recommended at 41 weeks of gestation or later in low-risk pregnancy due to stillbirth risk of 2-3 per 1000 deliveries 3
• Fetal mortality increases with advancing gestational age beyond 39 weeks 3

Maternal Diabetes

• Induction is indicated when delivery is in the best interest of mother and fetus, particularly with poor glycemic control 2
• Timing should be individualized based on glycemic control and fetal surveillance 4

Premature Rupture of Membranes

• Induction is indicated when membranes are prematurely ruptured and delivery is indicated 2

Other Medical Indications

• Rh problems requiring early delivery 2
• Intrahepatic cholestasis of pregnancy 4
• Intrauterine growth restriction (timing based on clinical features) 5

Elective Induction at 39 Weeks in Low-Risk Nulliparous Women

Key Benefits

• Cesarean delivery rate reduced from 22.2% to 18.6% (RR 0.84) - need to induce 28 women to prevent one cesarean 1
• Hypertensive disorders reduced from 14.1% to 9.1% (RR 0.64) 1
• No increase in adverse neonatal outcomes 1

Strict Eligibility Criteria (ARRIVE Trial)

You must ensure women meet ALL of the following criteria before offering elective induction at 39 weeks: 1

• Low-risk nulliparous women only (evidence does not extend to multiparous women) 1
• Gestational age ≥39 weeks 0 days (never before 39 weeks due to respiratory morbidity risk) 1
• Dating confirmed by early ultrasonography:
  • If certain last menstrual period: ultrasound <21 weeks 1
  • If uncertain last menstrual period: first-trimester ultrasound only 1
• No medical or obstetric complications 1

Critical Implementation Requirements

• Adequate facility capacity and staffing (nurses, anesthesiologists) must be available 1
• Shared decision-making is mandatory - discuss both options (induction vs expectant management) 1
• Medical/obstetric indications take priority for induction slots 1

Contraindications to Elective Induction

Absolute Contraindications

• Suspected fetal macrosomia is NOT an indication for induction - it doubles cesarean risk without reducing shoulder dystocia or neonatal morbidity 1
• Before 39 weeks 0 days gestation - associated with increased respiratory morbidity 1
• Previous cesarean delivery with misoprostol use - 13% uterine rupture risk 6

Relative Contraindications

• Unfavorable cervix without adequate time for cervical ripening 6
• Facilities lacking capacity for emergency cesarean delivery 1

Common Clinical Pitfalls to Avoid

Critical errors that worsen outcomes: 1, 6

1. Never induce before 39 weeks 0 days for elective reasons - early term neonates (37-38 weeks) have increased respiratory morbidity 1

2. Never use misoprostol in women with prior cesarean - rupture risk is 13% vs 1.1% with oxytocin 6

3. Never induce for suspected macrosomia alone - induction doubles cesarean risk without benefit 1

4. Never offer elective induction without confirmed dating by early ultrasound - risk of iatrogenic prematurity 1

5. Do not extrapolate ARRIVE findings to multiparous women - evidence is insufficient 1

Induction Methods Based on Indication

For Favorable Cervix

• Oxytocin with artificial rupture of membranes is the standard approach 6, 2

For Unfavorable Cervix

• Oral misoprostol solution 20-25 µg every 2-6 hours (preferred pharmacological method) 6
• Mechanical methods (Foley catheter) preferred in cardiac patients, cyanosis, or prior cesarean 6

Special Populations

• Cardiac disease or cyanosis: use mechanical methods to avoid systemic vascular resistance drops 6
• Advanced liver failure: avoid misoprostol (requires hepatic metabolism) 6
• Active cardiovascular disease: avoid dinoprostone (profound BP effects) 6