What is the initial management of preterm labor?

Initial Management of Preterm Labor

The initial management of preterm labor should include administration of broad-spectrum antibiotics, consideration of antenatal corticosteroids between 24-34 weeks gestation, and magnesium sulfate for neuroprotection when delivery is anticipated before 32 weeks. 1, 2, 3

Diagnosis and Initial Assessment

• Evaluate for signs of infection, placental abruption, and assess fetal well-being 2
• Perform fetal biometry, amniotic fluid volume assessment, and fetal Doppler waveform analysis 2
• Diagnose intraamniotic infection based on maternal temperature ≥38°C and other signs including maternal tachycardia, purulent cervical discharge, fetal tachycardia, and uterine tenderness 2
• Note that some cases of intraamniotic infection may not initially present with maternal fever, so diagnosis and intervention should not be delayed due to absence of fever 2

Pharmacological Management Based on Gestational Age

Antibiotics

• For PPROM at ≥24 weeks: Administer a 7-day course of antibiotic therapy with IV ampicillin and erythromycin for 48 hours followed by oral amoxicillin and erythromycin for 5 days 1, 3
• For PPROM at 20-23 6/7 weeks: Antibiotics can be considered to prolong latency (GRADE 2C) 1, 3
• Azithromycin can replace erythromycin if unavailable 1, 3
• Avoid amoxicillin-clavulanic acid due to increased risk of necrotizing enterocolitis 1, 3

Antenatal Corticosteroids

• Administer between 24+0 and 34+0 weeks gestation to accelerate fetal lung maturity 1, 2
• Not recommended until the time when neonatal resuscitation would be considered appropriate 1, 3
• A single course of corticosteroid treatment in two doses of 12 mg betamethasone or 6 mg of dexamethasone is recommended 4, 5
• Reduces risk of respiratory distress syndrome, intraventricular hemorrhage, periventricular leukomalacia, and necrotizing enterocolitis 1

Magnesium Sulfate

• Recommended for fetal neuroprotection when delivery is anticipated before 32 weeks 2, 3
• Reduces the incidence of cerebral palsy (relative risk, 0.68; 95% confidence interval, 0.54-0.87) 1
• Monitor for signs of magnesium toxicity including loss of deep tendon reflexes, respiratory depression, and cardiac conduction changes 6
• Contraindicated in patients with severe renal impairment; dosage adjustments required for moderate impairment 6

Tocolytic Therapy

• May be used to delay delivery for 48-72 hours to allow for administration of antenatal corticosteroids 1, 7
• Nifedipine (calcium channel blocker) and indomethacin (prostaglandin inhibitor) may be considered before 32 weeks 1, 7
• Limited evidence for improved neonatal outcomes despite short-term pregnancy prolongation 1

Management Based on Clinical Scenario

Preterm Labor with Intact Membranes

• Antibiotic treatment is not recommended due to lack of evidence of benefit and potential risks 1
• Consider tocolytics to delay delivery for administration of antenatal corticosteroids 1, 7

Preterm Prelabor Rupture of Membranes (PPROM)

• Administer broad-spectrum antibiotics to prolong pregnancy during expectant management at ≥24 weeks 1
• For previable PPROM (<20 weeks), offer both abortion care and expectant management options 1
• For periviable PPROM (20-23 6/7 weeks), consider antibiotics to prolong latency 1, 3

Monitoring and Follow-up

• Initial observation in hospital to ensure stability 2
• Monitor for signs of maternal complications such as hemorrhage or infection 2
• Daily temperature monitoring to screen for maternal fever 2
• Weekly outpatient visits for assessment of maternal vital signs, fetal heart rate, physical examination, and possible laboratory evaluation 2

Common Pitfalls to Avoid

• Delaying diagnosis and treatment of intraamniotic infection due to absence of maternal fever 2
• Using amoxicillin-clavulanic acid, which increases risk of necrotizing enterocolitis 1, 3
• Prolonged or repeated antibiotic courses beyond what would be used for PPROM at later gestational ages 3
• Administering antenatal corticosteroids and magnesium sulfate before the time when neonatal resuscitation would be appropriate 1, 3