Birth‐Related Subdural Haemorrhage in Asymptomatic Moderate‐to‐Late Preterm Neonates: Magnetic Resonance Imaging Features and Temporal Evolution

INTRODUCTION: Birth-related subdural haemorrhages (SDH) are common in asymptomatic neonates. While most resolve without long-term effects, their natural history in moderate-to-late preterm (MLP) neonates remains uncertain. Rebleeding into birth-related SDH is also sometimes suggested as an alternative explanation for SDH findings in suspected abusive head trauma. We aimed to assess the prevalence, distribution, risk factors and temporal evolution of birth-related SDH in asymptomatic MLP neonates, and to compare these to those reported in term neonates. METHOD: We reviewed a cohort of asymptomatic neonates born 32 + 0 to 36 + 6 weeks of gestation who underwent brain MRI scans shortly after birth (scan 1) and at term-equivalent age (scan 2). The presence, location and size of SDH were assessed using Four Quadrant Subdural (FQS) scoring reflecting the sum of the maximal thickness of SDH in each quadrant. Demographic and clinical factors were compared between neonates with and without SDH. RESULTS: SDH was identified in 48/189 neonates (25.4%) at scan 1. Most had multifocal haemorrhages in the posterior cranial fossa or posterior supratentorial regions. Neonates with SDH had higher birth weights than those without SDH and were more likely to be born vaginally. By scan 2, SDH had resolved in 75% and mean FQS score decreased by 71% in the remainder. CONCLUSION: SDH is common in MLP neonates, with a distribution similar to that of term neonates. Risk factors include higher birth weight and vaginal birth. Most birth-related SDH resolves by term-equivalent age, making it an unlikely explanation for SDH in older infants with suspected abusive head trauma.