Synopsis
Coordinate fetal-maturation treatment, magnesium neuroprotection and safe in-utero transfer according to gestation, likelihood of birth and maternal or fetal stability.
- Corticosteroids reduce prematurity-related neonatal morbidity when birth is likely soon; magnesium sulfate has a separate fetal neuroprotection purpose.
- NICE offers corticosteroids at 24+0–33+6 weeks, considers them at 34+0–35+6 and recommends individual discussion at 22+0–23+6.
- RCOG's corticosteroid guideline offers treatment through 34+6 weeks, so the 34th-week recommendation should be identified by source rather than silently merged.
- RCOG regimens include dexamethasone 6 mg intramuscularly every 12 hours for four doses, or betamethasone phosphate/acetate mixture 12 mg intramuscularly twice 24 hours apart; verify the actual preparation.
- For birth expected within 24 hours, discuss magnesium at 23+0–23+6, offer at 24+0–29+6 and consider at 30+0–33+6 weeks under NICE.
- Give magnesium sulfate 4 g intravenously over 15 minutes, then 1 g/hour until birth or 24 hours, whichever comes first.
- Check pulse, blood pressure, respiratory rate and tendon reflexes at least four-hourly during magnesium, with closer review and dose reduction or cessation for renal impairment.
Key red flags
Respiratory depression, absent tendon reflexes, marked weakness or worsening oliguria during magnesium treatment requires stopping the infusion and urgent senior assessment.
An unstable patient or an imminent birth requires local emergency readiness rather than automatic transfer to a distant neonatal unit.
Investigation priorities
Establish eligibility and prevent duplicate or excessive courses across different units.
Management branches
Preterm delivery is sufficiently likely within a clinically meaningful interval.
- Confirm gestation, previous courses and the anticipated birth plan, then discuss the appropriate NICE or RCOG gestational recommendation with the patient.
- Administer the selected intramuscular course, arrange diabetes monitoring where needed and transmit each administration time to the labour and neonatal teams.
- Consider only one repeat course below 34+0 weeks when the previous course was more than seven days ago and birth is very likely within 48 hours; give no more than two courses for preterm birth.
Key medicines
Betamethasone fetal-maturation courseFor betamethasone sodium phosphate/acetate mixture, give 12 mg intramuscularly twice, 24 hours apart, totalling 24 mg. The phosphate-only preparation common in the UK has different kinetics; confirm the formulation-specific maternity protocol.Use for fetal maturation is off label in relevant UK preparations; check diabetes management, prior courses and the risk of neonatal hypoglycaemia after late-preterm exposure.
Dexamethasone fetal-maturation alternativeGive dexamethasone 6 mg intramuscularly every 12 hours for four doses, a total of 24 mg; RCOG also recognises 12 mg intramuscularly twice 24 hours apart.Confirm the injectable formulation and prescribed course, do not mix partial regimens without a documented specialist decision, and count previous fetal-maturation courses.