What is the medical management for preterm delivery?

Medical Management for Preterm Delivery

The medical management of preterm delivery should include antenatal corticosteroids for fetal lung maturation when delivery is anticipated before 34 weeks, magnesium sulfate for neuroprotection when delivery is anticipated before 30 weeks, and appropriate antibiotics for preterm premature rupture of membranes (PPROM). 1

Antenatal Corticosteroids

• Administer a 2-day course of betamethasone (two doses of 12 mg IM, 24 hours apart) or dexamethasone (four doses of 6 mg IM, 12 hours apart) when preterm delivery is anticipated within 10-14 days at less than 34 weeks gestation 1
• Corticosteroids significantly reduce neonatal mortality, respiratory distress syndrome, and intraventricular hemorrhage 2
• Optimal timing is 1-7 days before delivery, with benefits seen even when administered less than 24 hours before delivery 3
• A single course is recommended; multiple courses should be avoided due to potential fetal growth restriction 3, 4
• A rescue course may be considered if more than 7 days have elapsed since the initial course and preterm birth remains likely before 34 weeks 5

Magnesium Sulfate for Neuroprotection

• Administer intravenous magnesium sulfate when delivery is anticipated before 30 weeks gestation to reduce the risk of cerebral palsy 1
• Can be considered up to 34 weeks gestation 1
• Reduces the incidence of cerebral palsy by approximately 32% without increasing mortality 1
• Monitor for maternal toxicity: assess deep tendon reflexes, respiratory rate, and serum magnesium levels 6
• Caution in patients with renal impairment; maintain urine output at ≥100 mL over four hours preceding each dose 6

Antibiotics

• For PPROM at ≥24 weeks: strongly recommended (GRADE 1B) 1, 7
• For PPROM at 20-23 6/7 weeks: can be considered (GRADE 2C) 1, 7
• For PPROM at <20 weeks: shared decision-making regarding benefits and risks 1, 7
• Recommended regimen: 7-day course with IV ampicillin and erythromycin for 48 hours, followed by oral amoxicillin and erythromycin for 5 days 7, 8
• Avoid amoxicillin-clavulanic acid due to increased risk of necrotizing enterocolitis 7, 8

Management Based on Gestational Age

Previable (<20 weeks)

• Offer both abortion care and expectant management options after counseling about maternal and fetal risks 1
• Antibiotics not clearly beneficial; requires shared decision-making 1

Periviable (20-23 6/7 weeks)

• Consider antibiotics to prolong latency 1
• Antenatal corticosteroids and magnesium sulfate not recommended until neonatal resuscitation would be considered appropriate 1

Viable (≥24 weeks)

• Administer antibiotics for PPROM 1, 7
• Give antenatal corticosteroids if <34 weeks 1
• Consider magnesium sulfate for neuroprotection if <30 weeks 1
• Tocolytic therapy may briefly delay delivery (48-72 hours) to allow for corticosteroid administration 1

Special Considerations

• For women with liver disorders, misoprostol (E1 prostaglandin) may be less suitable for labor induction as it requires hepatic metabolism to its active form 1
• In hepatitis C with high viral load, avoid invasive procedures (internal monitoring, fetal scalp sampling, vacuum extraction) to reduce vertical transmission risk 1
• For women with oesophageal varices, establish beta blockade or banding before delivery, and consider a short second stage of labor 1
• For women with cerclage and PPROM, either remove the cerclage or leave it in situ after discussing risks and benefits 1

Common Pitfalls to Avoid

• Prolonged or repeated antibiotic courses beyond standard regimens 1, 7
• Using amoxicillin-clavulanic acid, which increases risk of necrotizing enterocolitis 7, 8
• Administering antenatal corticosteroids or magnesium sulfate before the period when neonatal resuscitation would be appropriate 1
• Serial amnioinfusions and amniopatch are investigational and not recommended for routine care 1
• Continuous administration of magnesium sulfate beyond 5-7 days can lead to fetal bone abnormalities 6