Recent Guidelines on Antenatal Corticosteroids for Preterm Birth
Administer betamethasone 12 mg intramuscularly in two doses, 24 hours apart, to women with singleton pregnancies between 34 0/7 and 36 6/7 weeks of gestation who are at high risk of delivery within the next 7 days and before 37 weeks. 1
Standard Dosing Regimen
- For gestational ages 24 0/7 to 36 6/7 weeks: Betamethasone 12 mg intramuscularly, two doses given 24 hours apart 2, 3, 4
- If betamethasone is unavailable, dexamethasone 12 mg intramuscularly in two doses, 24 hours apart, is an acceptable alternative 2
- The optimal benefit window occurs when delivery happens within 24 hours to 7 days after administration 2, 4
Clinical Benefits
- Respiratory outcomes: Antenatal corticosteroids reduce respiratory distress syndrome by 29% (RR 0.71,95% CI 0.65-0.78) and decrease the need for respiratory support by 20% (RR 0.80,95% CI 0.66-0.97) 1, 5
- Severe respiratory morbidity: Reduction of 33% (RR 0.67,95% CI 0.53-0.84) in severe respiratory complications 1
- Mortality: Neonatal death is reduced by 22% (RR 0.78,95% CI 0.70-0.87) and perinatal death by 15% (RR 0.85,95% CI 0.77-0.93) 5
- Intraventricular hemorrhage: Probable reduction of 42% (RR 0.58,95% CI 0.45-0.75) 5
- Long-term neurodevelopment: Probable reduction in developmental delay in childhood (RR 0.51,95% CI 0.27-0.97) 5
Specific Indications for Administration
High-risk criteria include: 1, 2
- Preterm labor with intact membranes AND cervical dilation ≥3 cm OR ≥75% cervical effacement
- Spontaneous rupture of membranes before 37 weeks
- Expected preterm delivery for medical indications (gestational hypertension, preeclampsia) with planned delivery between 24 hours and 7 days
Critical Contraindications
Do NOT administer antenatal corticosteroids in the following situations: 1, 3
- Pregestational diabetes mellitus: Significantly increases risk of severe neonatal hypoglycemia 1, 4
- Low likelihood of delivery before 37 weeks: Avoid unnecessary exposure 1, 3
- Prior course in the late preterm period: Do not repeat courses for late preterm delivery 3
Special Populations
Consider administration (with shared decision-making) for: 1, 2
- Multiple gestations reduced to singleton on or after 14 0/7 weeks of gestation
- Pregnancies with fetal anomalies
- Patients expected to deliver in <12 hours
For twin pregnancies: 3
- Less than 34 weeks: Administer standard regimen
- Late preterm period (34-36 6/7 weeks): Evidence is insufficient; consider case-by-case with shared decision-making
Important Clinical Considerations
- Do not delay medically indicated delivery to complete the steroid course in the late preterm period 3
- Neonatal hypoglycemia monitoring is essential: While betamethasone increases hypoglycemia risk, 93% of cases are mild, self-limited, and resolve within 24 hours 3
- Thorough counseling is mandatory: Patients must understand that long-term neurodevelopmental risks remain uncertain despite established short-term benefits 1, 2
- Single course only: Routine repeat or "rescue" courses are not recommended in the late preterm period 4
Common Pitfalls to Avoid
- Overuse in low-risk patients: Do not administer to women with low probability of preterm delivery, as this exposes infants to unnecessary risks without benefit 1
- Use in diabetic patients: The increased risk of severe neonatal hypoglycemia outweighs benefits in women with pregestational diabetes 1, 4
- Timing errors: Maximum benefit requires delivery within 7 days of administration; efficacy diminishes beyond this window 2, 4
- Repeat dosing in late preterm period: Unlike earlier gestational ages where repeat courses may be considered after 7 days, this is not recommended for late preterm delivery 3
Special Context: Maternal Liver Disease
- For pregnant patients with HELLP syndrome or acute fatty liver of pregnancy, administer high-dose dexamethasone or betamethasone for fetal lung maturation if delivery is planned before 35 weeks 2
- Corticosteroids should NOT be given to improve maternal outcomes in HELLP syndrome—only for fetal lung maturation 2