What is the primary treatment for preterm birth syndrome?

Primary Treatment for Preterm Birth Syndrome

The primary treatment for preterm birth syndrome is antenatal corticosteroids (betamethasone 12 mg IM every 24 hours for 2 doses) administered to pregnant women at risk of preterm delivery, which substantially reduces neonatal mortality, respiratory distress syndrome, intraventricular hemorrhage, and sepsis. 1

Antenatal Corticosteroids: The Cornerstone of Treatment

Standard Dosing and Timing

• Administer a single course of betamethasone (2 doses of 12 mg IM, 24 hours apart) or dexamethasone (24 mg total in divided doses over 24 hours) to all pregnant women between 24 0/7 and 33 6/7 weeks of gestation at risk of preterm delivery within 7 days 2, 3
• This intervention reduces neonatal mortality (RR 0.60), respiratory distress syndrome (RR 0.53), and intraventricular hemorrhage 4
• Benefits extend across all gestational ages, genders, and races 4

Extended Gestational Age Indications

• For late preterm delivery (34 0/7 to 36 6/7 weeks), offer betamethasone to women at high risk of delivery within 7 days who have not received prior corticosteroids (GRADE 1A) 1
• The ALPS trial demonstrated reduced need for respiratory support (11.6% vs 14.4%, RR 0.80) and severe respiratory morbidity (8.1% vs 12.1%, RR 0.67) 1
• Consider corticosteroids starting at 23 0/7 weeks for women at risk of delivery within 7 days, based on family decisions regarding resuscitation 2, 3

Repeat Dosing Strategy

• Administer a single rescue course if gestational age remains <34 0/7 weeks, delivery risk persists within 7 days, and >14 days have elapsed since the initial course 2, 3
• Rescue courses may be given as early as 7 days from the prior dose if clinically indicated 2, 3

Magnesium Sulfate for Neuroprotection

Indications and Administration

• Administer magnesium sulfate for fetal neuroprotection when delivery is anticipated before 32 weeks' gestation 1, 5, 6
• This reduces cerebral palsy incidence (RR 0.68) without increasing mortality (RR 1.04) 1
• For periviable deliveries (23-25 weeks), give magnesium sulfate if delivery of a potentially viable infant is anticipated 1, 5

Critical Safety Monitoring

• Monitor for maternal respiratory depression (maintain >16 breaths/min) and check patellar reflexes before each dose 7
• Therapeutic serum levels range from 3-6 mg/100 mL (2.5-5 mEq/L); reflexes disappear at 10 mEq/L with risk of respiratory paralysis 7
• Never combine magnesium sulfate with short-acting nifedipine, as this causes uncontrolled hypotension and fetal compromise 8
• Monitor neonates for hypotonia, respiratory depression, and hypermagnesemia after birth 5, 6

Postnatal Surfactant Therapy

Respiratory Support Algorithm

• For preterm infants <30 weeks requiring mechanical ventilation due to severe RDS, administer surfactant after initial stabilization (GRADE 1) 1
• Alternatively, initiate CPAP immediately after birth with selective surfactant administration rather than routine intubation with prophylactic surfactant (GRADE 1) 1
• Early rescue surfactant (<2 hours of age) reduces mortality, air leaks, and chronic lung disease compared to later administration 1

Surfactant Selection

• Both animal-derived and newer synthetic surfactants with SP-B-like activity effectively decrease respiratory morbidity and mortality 1

Adjunctive Therapies

Antibiotic Administration

• For preterm PROM ≥24 weeks: administer broad-spectrum antibiotics (7-day course: IV ampicillin and erythromycin for 48 hours, then oral amoxicillin and erythromycin for 5 days) to prolong pregnancy and reduce neonatal infections (GRADE 1B) 1, 8
• For preterm PROM 20-23+6 weeks: antibiotics may be considered (GRADE 2C) 1, 8
• Avoid amoxicillin-clavulanic acid due to increased necrotizing enterocolitis risk 8
• Do not give antibiotics for preterm labor with intact membranes—no benefit demonstrated and potential harm exists 1, 8

Tocolytic Therapy

• Use nifedipine or indomethacin to delay delivery 48-72 hours, allowing time for corticosteroid administration and maternal transfer to tertiary care 8
• Evidence supports efficacy after 26 weeks' gestation, though data before 26 weeks are limited 1
• Tocolysis provides time for interventions but has not consistently improved neonatal outcomes 1

Synergistic Effects

Antenatal corticosteroids and postnatal surfactant work independently and additively to reduce mortality, RDS severity, and air leaks 1. The combination provides superior outcomes compared to either intervention alone, with corticosteroids reducing mortality (RR 0.62), RDS (RR 0.65), and surfactant use (RR 0.45) 1.

Critical Pitfalls to Avoid

• Do not withhold corticosteroids from women with ruptured membranes or multiple gestations—benefits extend to these populations 2, 3
• Avoid corticosteroids in women with low likelihood of delivery before 37 weeks (GRADE 1B) 1
• Do not administer continuous magnesium sulfate beyond 5-7 days—this causes fetal hypocalcemia, skeletal demineralization, and osteopenia 7
• Monitor neonatal glucose closely after late preterm corticosteroid exposure, as hypoglycemia occurs more frequently (though typically mild and self-limited within 24 hours) 1
• Ensure adequate renal function before magnesium sulfate administration and maintain urine output ≥100 mL in the 4 hours preceding each dose 7