Background Sudden and unexpected postnatal collapse (SUPC) of a healthy newborn infant is a rare event, which carries a high risk of mortality and significant neurodisability in survivors. An underlying condition can be found in 60% of cases who undergo detailed postmortem but in the remainder there are important associations with prone position, breast feeding and primiparous status. The authors undertook a prospective study to ascertain the population incidence of SUPC in the UK.

Methods Cases were referred through the British Paediatric Surveillance Unit reporting scheme over a 13-month period. Infants were at ≥37 weeks of gestation, had an Apgar score of ≥8 at 5 min, collapsed within 12 h in hospital requiring positive pressure ventilation and either died or received ongoing intensive care. Data were collected on maternal and infant characteristics, clinical investigations and 1-year outcome.

Findings 45 cases were reported, an incidence of 0.05/1000 live births of whom 12 infants died. In 15/45 infants, an underlying disease/abnormality was determined. In 30/45 cases (0.035/1000 live births), no such cause was found, but in 24, the clinical/pathological diagnosis was airway obstruction during breast feeding or in prone position. Mothers were commonly primiparous and unattended by clinical staff before collapse was recognised. Approach to investigation was highly disparate and frequently very limited. Of the 30 infants with no underlying disease/abnormality, 22 (73%) developed a postasphyxial encephalopathy and 10 had a poor outcome (33%) – 5 died and 5 had neurological sequelae at 1 year.

Interpretation SUPC is rare in any one centre and there is no standard approach to investigation. In those cases where collapse is not due to an underlying abnormality, breast feeding and prone position are important associations. Guidelines for safe postnatal care of infants should include appropriate vigilance of infants particularly where mothers are primiparous or where ability to assess the baby may be impaired.