What is the recommended treatment with betamethasone (corticosteroid) for pregnant women at risk of preterm delivery to prevent Respiratory Distress Syndrome (RDS) in newborns?

Betamethasone for Prevention of Respiratory Distress Syndrome in Preterm Delivery

For pregnant women at risk of preterm delivery, administer 2 doses of 12 mg intramuscular betamethasone 24 hours apart to reduce neonatal respiratory distress syndrome, severe respiratory morbidity, and mortality. 1

Specific Indications for Treatment

Late Preterm Period (34 0/7 to 36 6/7 weeks)

• Offer betamethasone to singleton pregnancies between 34 0/7 and 36 6/7 weeks of gestation who are at high risk of preterm birth within the next 7 days and before 37 weeks of gestation 1
• High-risk criteria include: preterm labor with intact membranes and cervical dilation ≥3 cm or ≥75% cervical effacement, spontaneous rupture of membranes, or expected preterm delivery for maternal/fetal indications such as preeclampsia 2

Earlier Gestational Ages (<34 weeks)

• Betamethasone substantially reduces death, respiratory distress syndrome, intraventricular hemorrhage, and sepsis when administered before 34 weeks of gestation 1
• A single course is recommended for women between 24 0/7 and 33 6/7 weeks at risk of delivery within 7 days 3

Dosing Protocol

Standard regimen: 12 mg intramuscular betamethasone given as 2 doses, 24 hours apart 1, 4

• The 24-hour interval is the established standard based on the landmark ALPS trial 1
• While one study suggested 12-hour intervals may be effective, the 24-hour protocol remains the guideline-recommended approach 5
• Doubling the betamethasone dose provides no additional benefit 6

Clinical Benefits (Based on ALPS Trial Data)

Respiratory outcomes significantly improve with betamethasone:

• Need for respiratory support reduced from 14.4% to 11.6% (RR 0.80,95% CI 0.66-0.97) 1
• Severe respiratory morbidity reduced from 12.1% to 8.1% (RR 0.67,95% CI 0.53-0.84) 1, 2
• Greater efficacy observed in male versus female infants 6

Absolute Contraindications

Do NOT administer betamethasone in:

• Pregnant patients with pregestational diabetes mellitus due to significantly increased risk of worsening neonatal hypoglycemia 1, 2, 7
• Pregnant patients with low likelihood of delivery before 37 weeks to avoid unnecessary exposure 1, 2

Special Populations to Consider

Betamethasone may be considered (weaker recommendation) for: 1, 2

• Multiple gestations reduced to singleton on or after 14 0/7 weeks
• Patients with fetal anomalies
• Those expected to deliver in <12 hours

Risks and Monitoring

Neonatal Hypoglycemia

• More common with betamethasone exposure but typically mild and self-limited 1, 4, 2
• 93% of cases resolve within 24 hours 4, 2
• Infants with hypoglycemia were actually less likely to have prolonged NICU stays (>3 days) 1
• Use skin-to-skin care immediately after birth to reduce hypoglycemia risk 7

Long-term Neurodevelopmental Concerns

• Long-term risks remain uncertain - patients must be counseled about this uncertainty 1
• Some evidence suggests potential increased cerebral palsy risk with repeated courses (2.9% vs 0.5% with single course) 8
• Only administer a single course - avoid routine repeat dosing 8

Critical Clinical Pitfalls to Avoid

1. Do not use in diabetic patients - the neonatal hypoglycemia risk outweighs benefits in pregestational diabetes 1, 7
2. Do not administer to low-risk patients - avoid overuse in women unlikely to deliver preterm 1
3. Do not give multiple routine courses - stick to single course unless specific rescue indications exist 8, 3
4. Ensure proper timing - maximum benefit when delivery occurs within 7 days of administration 1, 2

Special Indication: Fetal Lung Lesions

For microcystic congenital pulmonary airway malformation (CPAM) with nonimmune hydrops fetalis, use betamethasone 12.5 mg intramuscularly every 24 hours for 2 doses 4