Transition to extrauterine life in extremely preterm infants: a narrative review of physiology-based cardiovascular and cerebral monitoring

Background and Objective: The transition from fetal to neonatal life is a complex physiological process involving coordinated respiratory, cardiovascular, and cerebrovascular adaptations. While generally well tolerated in term infants, it represents a period of augmented vulnerability in extremely preterm neonates. Profound organ immaturity, persistent transitional shunts, unstable vascular resistance, and impaired cerebrovascular autoregulation may result in maladaptive responses and increased risk of mortality and neurodevelopmental impairment. The aim of this review was to synthesize current evidence on transitional physiology, cardiovascular adaptation, and cerebrovascular autoregulation in extremely preterm infants, with emphasis on the potential role of multimodal monitoring in the detection and management of neonates with complicated postnatal adaptation.

Methods: This narrative review was informed by a non-systematic literature search conducted in PubMed and Embase, using predefined keywords related to neonatal transition, extreme prematurity, cerebrovascular adaptation and cerebral monitoring. Studies published up to November 2025 were included, limited to English or Spanish. Additional studies were identified through manual reference screening.

Key Content and Findings: We review cardiovascular adaptation during transition, highlighting right ventricular performance, antenatal determinants of transitional physiology, and the limitations of conventional clinical markers, such as blood pressure and heart rate. The role of targeted neonatal echocardiography as a functional bedside tool for assessing ventricular adaptation, shunt physiology and systemic blood flow is discussed. Emerging techniques, including tissue Doppler imaging and speckle tracking echocardiography, are considered for detecting early myocardial dysfunction. We also review cerebral monitoring modalities, including near-infrared spectroscopy and amplitude-integrated electroencephalography, in the context of immature autoregulation, enhanced brain vulnerability and their integration within a multimodal monitoring framework.

Conclusions: An integrated, multimodal monitoring approach that combines cardiovascular and cerebral assessments and is interpreted within the context of biological heterogeneity, may support physiology-based care in extremely preterm infants. While promising, its application should be approached with caution in the absence of standardized frameworks and outcome-based validation. Further research is needed to determine its impact on clinically meaningful outcomes.