The first aim of this study is to analyse perinatal risk factors leading to hypoxic ischaemic encephalopathy in term and near term neonates born in Switzerland who were admitted to the neonatal and intensive care units offering hypothermia therapy.

Further, investigators would like to analyse the influence of these perinatal risk factors on the severity of encephalopathy during and after hypothermia therapy.

Encephalopathy of the neonate could have different aetiologies. Perinatal asphyxia leading to hypoxia-ischaemia is frequent ,1-2 per 1000 life born neonates are affected. Hypoxic ischaemic encephalopathy is one of the most important causes for adverse neurodevelopmental outcome, cerebral palsy, epilepsy and hearing and vision deficiencies in term and near term neonates. Til now, hypothermia therapy is the only therapy reducing the risk of adverse neurodevelopmental outcome and is nowadays standard of care. In this study investigators would like to analyse perinatal risk factors causing HIE and their influence on the Sarnat Score on day 1 and 3 of life (during hypothermia therapy) and on day 4 of life (after hypothermia therapy).

Inclusion Criteria:

• This study includes data of neonates suffering from hypoxic-ischaemic encephalopathy born with a gestational age > 35 0/7 weeks, who were admitted to the neonatal and intensive care units in Switzerland between 2011-2013 and were treated with therapeutic hypothermia.

Exclusion Criteria:

• Neonates with hypoxic-ischaemic encephalopathy, born with a gestational age < 35 0/7 weeks or without hypothermia treatment or syndromal diseases or with malformations were excluded.
• Further, children without consent to research use were excluded.

Neonates born >35 0/7 gestational weeks with clinical signs of hypoxic encephalopathy with Apgar Score<5 with 10minutes of life, mechanical ventilation with 10minutes of life, pH 7.0 or BE -16mmol/L, lactate >12mmol/L within 60minutes after birth, and seizures or Sarnat staging II-III or Thompson Score >7.