Betamethasone (Antenatal Corticosteroids)

How it works

As a potent glucocorticoid crossing the placenta, it promotes fetal surfactant production and lung maturation, reducing the risk and severity of neonatal respiratory distress syndrome.

Prescribing in practice

• Optimal neonatal benefit depends on timing relative to anticipated delivery within the recommended gestational window, so a course should be given when preterm birth is genuinely likely rather than indiscriminately.
• It transiently raises maternal blood glucose, requiring closer glucose monitoring particularly in women with diabetes.
• Repeat courses are used selectively under specialist guidance because of potential effects on fetal growth.

Monitoring

Monitor maternal blood glucose, especially in diabetes, and fetal wellbeing as part of the preterm birth pathway.

Counselling the patient

• Explain that the injections are given to help the baby's lungs mature before an early birth.
• Women with diabetes may need closer blood sugar monitoring for a few days.
• Attend follow-up so timing and any need for further doses can be assessed.

Evidence & guidelines

Antenatal corticosteroids reduce neonatal respiratory distress and mortality in anticipated preterm birth, supported by Cochrane evidence and NICE guidance.