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Corticosteroid (Fetal Lung Maturation) Pregnancy: Indicated in pregnancy (24–35+6 weeks) — standard of care

Betamethasone (Antenatal Corticosteroids)

Brand names: Celestone Chronodose, Betnesol (betamethasone sodium phosphate)

Adult dose

Dose: 12 mg IM, repeated once 24 hours later (total 2 doses = 24 mg)
Route: Deep IM
Frequency: Two doses 24 hours apart
Max: 24 mg total (2 × 12 mg)
RCOG/NICE: indicated 24–35+6 weeks when preterm birth is anticipated within 7 days. A single rescue course may be considered if a first course given >7 days previously and patient still <34 weeks. Give both doses even if delivery seems imminent — even partial course beneficial.

Paediatric dose

Route: N/A
Frequency: N/A
Max: N/A
Administered to mother — drug crosses placenta to act on fetal lungs

Dose adjustments

Renal

No dose adjustment required

Hepatic

No dose adjustment required

Clinical pearls

  • Single course reduces neonatal RDS, IVH, necrotising enterocolitis, and neonatal death — one of the most impactful interventions in obstetrics
  • Full benefit achieved 24–48h after first dose — but even partial treatment is beneficial
  • Diabetic mothers: blood glucose monitoring every 1–2h for 48h post-administration — may need insulin infusion
  • Fetal CTG changes: reduced baseline variability in 24–48h post-dose is a known effect — not fetal distress
  • Rescue courses (one only): recommended if >7 days since first course and still at risk of preterm birth <34 weeks

Contraindications

  • Systemic infection without antibiotic cover (relative — benefit usually outweighs risk)
  • Active maternal TB without treatment (relative)

Side effects

  • Maternal hyperglycaemia (significant — monitor blood glucose 6-hourly for 48h in diabetic mothers)
  • Fetal heart rate variability may transiently decrease (within 24–48h — do not misinterpret as deterioration)
  • Pulmonary oedema (if concurrent tocolysis with beta-agonists)
  • Neonatal adrenal suppression (if multiple courses)

Interactions

  • Beta-agonist tocolytics — increased risk of pulmonary oedema
  • Antidiabetic agents — hyperglycaemia requires insulin dose adjustment

Monitoring

  • Blood glucose (all women; intensive in diabetics)
  • Fetal CTG
  • Signs of preterm birth progression
  • Pulmonary status (if concurrent tocolysis)

Reference: BNFc; NICE NG25 Preterm Labour and Birth; RCOG Antenatal Corticosteroids Guideline (2022); BNF. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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