Birth asphyxia: incidence, clinical course and outcome in a Swedish population

Abstract

A total of 42,203 live infants were born in Göteborg in 1985-1991, and 292 term infants had Apgar scores < 7 at 5 min. Infants with congenital malformations, infections and opioid-induced respiratory depression were excluded and thus 227 infants were included in the birth asphyxia group, which formed the basis of this retrospective study. Clinical signs of mild, moderate or severe hypoxic-ischemic encephalopathy (HIE) were present in 65 infants, and in another 10 infants, sedated and on controlled ventilation, HIE was assumed but grading was not possible. The incidences of Apgar scores < 7 at 5 min, birth asphyxia and birth asphyxia with HIE were 6.9, 5.4 and 1.8 per 1,000 live born infants: 95% of infants resuscitated with bag and mask ventilation only, did well, compared with 1 of 11 in whom resuscitation included adrenaline. Seizures occurred in 27 of 227 infants, beginning in 18 infants within 12 h of birth. Small-for-gestational-age (SGA) infants were overrepresented in the birth asphyxia group but not in the birth asphyxia-HIE group. All infants with severe HIE died or developed neurological damage. Half of the infants with moderate, and all of the infants with mild, HIE were reported to be normal at 18 months of age. A total of 0.3 per 1,000 live born infants died and 0.2 per 1,000 developed a neurological disability related to birth asphyxia. The disabilities were dyskinetic (4), tetraplegic (2), spastic diplegic (2), cerebral palsy and mild neuromotor dysfunction (1). The relatively low incidences of birth asphyxia and HIE were probably due to effective antenatal care.