A study of symptomatic birth asphyxia : its immediate manifestations and long term significance
Despite improvement in healthcare during pregnancy and childbirth, intrapartum asphyxia remains a substantial problem. Mild degrees are common, producing signs of fetal distress during labour and temporary depression of vital function at birth, but, in the absence of neonatal sequelae, are generally benign without longer term implications. More severe degrees of intrapartum asphyxia may be followed by disturbances of function in many body systems, most notably the central nervous system; a situation referred to as symptomatic birth asphyxia. Although such disturbances are often transient, there is a risk of permanent neurological handicap in some cases. Acute, neonatal, neurological consequences of intrapartum asphyxia have long been recognised, but,in the literature, differences remain of the detailed neurological findings described, of the interpretation of their immediate significance and of the prognostic significance attributed to such neonatal findings. To look at these aspects, a prospective study of symptomatic birth asphyxia has been conducted. Fifty, mainly mature, infants were identified in the early hours of life by their fulfillment of preselected criteria of symptomatic birth asphyxia. Their general characteristics, antenatal and intrapartum factors, birth condition and the abnormalities of performance and behaviour which the infants displayed are reported. The infants' status over the early neonatal period, carefully assessed by repeated neurological examinations, appropriate investigation, and physiological recording of electroencephalograph, polygraph, and sucking and respiratory patterns, is described and illustrated. The majority of the children have been the subject of regular assessments to primary school age to determine their outcome. Three infants died in the first days of life and a fourth, who was severely brain damaged, in later infancy. Five children have significant handicap, seven mild degrees of neurological or developmental abnormality, while the remaining thirty-four children are considered normal. A number of neonatal events and findings correlated well with outcome. Indicators of condition at birth, the occurrence of apnoeic episodes, prolonged gasping respirations, a phase of apathy, tonic seizures, prolonged depression of feeding reflexes, hypothermia, and certain patterns of neurological abnormality - persistent hypotonia, marked extensor hypertonus with preceding and succeeding hypotonic phases, bulbar palsy and ophthalmoplegia, all bore a highly significant relationship to poor outcome. Of these, the abnormalities of muscle tone and ophthalmoplegia correlated strongly with outcome; the consideration of additional, significant risk factors did not add to their predictive value.