ACOG Guidelines: Antenatal Corticosteroids Beyond 34 Weeks (Late Preterm Period)

The Core Recommendation (ACOG/SMFM)

• Gestational age: 34 0/7 to 36 6/7 weeks
• Delivery risk: High risk of preterm birth within 7 days
• No prior course: Patient has not previously received a full course of antenatal corticosteroids (ACS)

Eligible Indications (Who Qualifies at 34-36 6/7 Weeks)

Key Conditions / Contraindications

• No rescue course: Gestational age ≥34 0/7 weeks is a contraindication to a rescue course of steroids
• No prior ACS course: Betamethasone should only be offered if the patient has not received a previous course
• Chorioamnionitis: Contraindication
• Diabetes (pregestational or gestational): Use with caution - these patients were excluded from the original ALPS trial; significant neonatal hypoglycemia risk
• Multiple gestations: ALPS enrolled only singletons; ACOG guidance is less definitive for multiples at late preterm

Drug Regimen

• 12 mg IM, two doses 24 hours apart
• Betamethasone acetate + betamethasone sodium phosphate combination

Benefits (from ALPS Trial)

• Overall need for neonatal respiratory support (primary outcome)
• Severe respiratory complications: 12.1% (placebo) vs 8.1% (betamethasone) - RR 0.67 (95% CI 0.53-0.84, P <.001)
• Transient tachypnea of the newborn (TTN)
• Bronchopulmonary dysplasia (BPD)
• Surfactant use

• Significant reduction in CPAP use ≥2 hours (RR 0.78, 95% CI 0.65-0.94)
• Significant reduction in surfactant use (RR 0.61, 95% CI 0.38-0.99)
• No significant difference in RDS rate or NICU admission overall

Risks and Concerns

• Patients with diabetes require individualized decision-making
• Neonatal glucose monitoring is mandatory after late preterm ACS

What the Long-Term Follow-Up Studies (2024-2026) Show

1. Neurodevelopmental outcomes (ALPS Follow-Up, JAMA 2024, PMID 38656759): No adverse neurodevelopmental effects at age 6-7 years. General Conceptual Ability score <85 occurred in 17.1% (betamethasone) vs 18.5% (placebo) - adjusted RR 0.94 (not significant). This reassured clinicians that late preterm steroids do not harm long-term brain development.
2. Childhood pulmonary outcomes (Gyamfi-Bannerman et al., Obstet Gynecol 2026, PMID 41570323): No difference in the composite pulmonary outcome (abnormal spirometry, asthma) at age 6+. Children exposed to betamethasone actually had less wheezing/whistling (RR 0.88). This further supports safety.

What ACOG Does NOT Recommend Beyond 34 Weeks

• Rescue course at ≥34 weeks: contraindicated
• Repeat/multiple courses: not recommended in any gestational period
• Term elective cesarean (37-38 6/7 weeks): Corticosteroids are sometimes discussed for elective cesarean at term, but ACOG does not currently recommend routine ACS for term cesarean as standard practice - evidence does not support it
• Steroids at ≥37 weeks: No recommendation for routine use

Comparison with Other Guidelines

Summary of Key Points

1. ACOG supports late preterm ACS (34 0/7-36 6/7 wks) only for at-risk singletons with no prior course and delivery expected within 7 days
2. Betamethasone is the agent of choice; do not use for rescue courses ≥34 weeks
3. Main benefit is reduced respiratory morbidity; main risk is neonatal hypoglycemia - mandatory glucose monitoring
4. Long-term neurodevelopmental and pulmonary safety is now confirmed by 2024-2026 ALPS follow-up data
5. Use is not recommended at ≥37 weeks or for routine term cesarean

• Creasy & Resnik's Maternal-Fetal Medicine, 9th ed., Chapter 38 (Antenatal Corticosteroids section)
• ALPS Trial (Gyamfi-Bannerman et al.)
• ALPS Neurodevelopmental Follow-Up, JAMA 2024 (PMID 38656759)
• Late Preterm ACS Meta-Analysis 2025, AJOG MFM (PMID 40418984)
• Childhood Pulmonary Outcomes ALPS 2026, Obstet Gynecol (PMID 41570323)