Shortened Courses of Antenatal Steroids in Preterm Births: An Observational Study.

OBJECTIVE

To describe current variations in antenatal steroid (AS) course durations in England, Wales, and Scotland according to gestational age, region, and drug. A secondary objective was to assess the availability of AS course duration data over time and by region.

DESIGN

Population based observational study.

SETTING

UK perinatal practice.

SAMPLE: Routinely collected data from the National Neonatal Audit Programme (NNAP) relating to preterm infants (< 34 weeks) born between January 2024 and February 2025.

METHODS

The numbers and proportions were calculated of: 1. women receiving a complete course of AS, 2. AS course duration availability, 3. length of AS course categorised as short (< 18 h), standard (18-36 h), or long (> 36 h). Descriptive statistics and Chi-squared tests assessed variation by region, drug, gestational age, and month for course duration, and by region and month for data availability.

OUTCOME MEASURES: Primary: proportion of complete AS courses classified as short. Secondary: proportion of complete AS courses with course duration data available.

RESULTS

Among 13 489 preterm births (< 34 weeks), 8640 were exposed to a complete antenatal steroid (AS) course; course duration data was available for 4428 (51.3%). Among these, 2069 (46.7%) were short, 2202 (49.7%) standard, and 157 (3.5%) long. The proportion of mothers receiving short AS courses were consistent over time but varied widely by region (Northern 17/223: 7.62%, North-West 359/588 61.05% p < 0.001). Short courses were more commonly used with dexamethasone (1047/1928: 54.30%) than betamethasone (847/2081: 40.75%) (p < 0.001). The proportion of full courses with documented course duration data improved from 35.3% (223/631) in March 2024 to 61.5% (339/551) by February 2025 (p < 0.001), ranging regionally from 30.5% (156/512, London South) to 67.6% (223/330, Northern).

CONCLUSION

Despite national and international guidelines, shortened AS courses are common and vary by region. Variation in course duration undermines current efforts to evaluate and improve perinatal care. Clinicians should review their AS practices and guidance and ensure accurate documentation of drug type and timing.