What is the recommended treatment with betamethasone (antenatal corticosteroid) for a pregnant female at 24-33 weeks gestation at risk of preterm labor?

Betamethasone for Preterm Labor (24-33 Weeks Gestation)

Administer betamethasone 12 mg intramuscularly in two doses, 24 hours apart, to all pregnant women between 24 0/7 and 33 6/7 weeks gestation who are at risk of preterm delivery within the next 7 days. 1, 2, 3

Standard Dosing Protocol

• The regimen is betamethasone 12 mg IM × 2 doses, given 24 hours apart 4, 5, 1
• This represents a single "course" of antenatal corticosteroids and is the standard of care for this gestational age range 2, 3
• Maximum benefit occurs when delivery happens between 24 hours and 7 days after the first dose 1
• Even if delivery is imminent (expected in <12 hours), still administer at least one dose, as this improves neurodevelopmental outcomes 2

Clinical Benefits That Improve Mortality and Morbidity

• Reduces neonatal mortality and severe respiratory morbidity by 33% (RR 0.67) 5, 1
• Decreases need for respiratory support by 20% (RR 0.80) 5, 1
• Reduces respiratory distress syndrome by 29% (RR 0.71) 5
• Decreases intraventricular hemorrhage, neonatal sepsis, and death 4, 1

Specific Indications for Administration

Administer betamethasone when any of the following high-risk criteria are present: 6, 4, 5

• Preterm labor with intact membranes AND cervical dilation ≥3 cm OR cervical effacement ≥75%
• Spontaneous rupture of membranes at 24-33 weeks
• Medically indicated preterm delivery anticipated within 24 hours to 7 days (e.g., preeclampsia, fetal growth restriction, oligohydramnios)

Multiple Gestations

• Administer the standard regimen (same dose, same interval) for twin pregnancies at 24-33 weeks gestation 5, 1, 3
• The dosing does NOT change for twins—use the same protocol as for singletons 2, 3

Critical Contraindications

Do NOT administer betamethasone in the following situations: 6, 4, 5

• Pregestational diabetes mellitus (Type 1 or Type 2 diabetes)—this significantly increases risk of severe neonatal hypoglycemia 6, 4, 5
• Low likelihood of delivery before 37 weeks—avoid unnecessary fetal exposure 6, 4, 5

Note: Gestational diabetes is NOT a contraindication; only pregestational diabetes is contraindicated 2

Repeat or Rescue Courses

• A single repeat course may be considered if <34 weeks gestation, >14 days have passed since the first course, and there is renewed imminent risk of delivery within 7 days 3, 7
• Rescue courses can be given as early as 7 days after the prior dose if clinically indicated 3, 7
• Routine multiple courses are NOT recommended 2, 8

Important Risks and Counseling Points

• Neonatal hypoglycemia is more common with betamethasone exposure, but 93% of cases are mild and resolve within 24 hours 6, 4
• Infants with hypoglycemia actually had shorter NICU stays than those without hypoglycemia in the ALPS trial 6
• Long-term neurodevelopmental effects remain uncertain—patients must be counseled about this uncertainty despite clear short-term benefits 6, 5

Common Pitfalls to Avoid

• Do NOT delay medically indicated delivery to complete the steroid course—maternal and fetal safety take priority 4, 5
• Do NOT withhold steroids in diabetic patients with gestational diabetes—only pregestational diabetes is a contraindication 2
• Do NOT administer to low-risk patients with minimal chance of delivery before 37 weeks—this exposes infants to unnecessary risks 6, 5
• Do NOT use a 12-hour interval between doses—while one study suggested this might be acceptable 9, the standard 24-hour interval remains the evidence-based recommendation 4, 5, 1, 2

Special Circumstances at the Margins (23 and 34 Weeks)

• At 23 0/7 to 23 6/7 weeks: Consider administration if active resuscitation is planned and delivery is anticipated within 7 days, based on family wishes 3, 7
• At 34 0/7 to 34 6/7 weeks: May be considered in selected high-risk cases, though this falls into the "late preterm" category with different risk-benefit considerations 2, 8