Encephalopathy In Term Infants Research Articles

The Continuing Fall in Incidence of Hypoxic-Ischaemic Encephalopathy in Term Infants

Objective To examine trends in incidence of hypoxic-ischaemic encephalopathy in term infants over a twenty-one year period. Design A retrospective analysis of medical records of all term infants admitted to a neonatal unit with hypoxic-ischaemic encephalopathy during the years 1992–1996 (period C) and a comparison with data from the years 1976–1980 (period A) and 1984–1988 (period B) from the same unit (previously published1). Setting A District Health Authority in Central England serving a population of about 450,000. Sample All term infants admitted with clinical features of hypoxic-ischaemic encephalopathy. Main outcome measures Incidence of three grades of hypoxic-ischaemic encephalopathy, disability and mortality. Results In each five year period there were similar numbers of births. Over the time-span of this study the stillbirth rate and neonatal mortality rate has consistently fallen. The overall incidence of hypoxicischaemic encephalopathy in term infants was significantly lower (P < 0.001; OR 0.42 CI 0.29–0.59) in the present study period (C) compared with the earlier study period B (1.9 vs 4.6 per 1000 total live births). The fall in moderately and severely affected infants between the present and the first study period was significant (1.2 vs 2.6 per 1000 total live births, P < 0.001: OR 0.46 CI 0.29–0.72). The number of deaths and the incidence of cerebral palsy in survivors fell progressively over the 21 years spanned by this study. Conclusion This study shows that the incidence of hypoxic-ischaemic encephalopathy and its sequelae in term infants has fallen significantly. The use of cardiotocography and caesarean section rates have risen but the relative contributions of changes in clinical practice are uncertain.

Maternal thyroid disease: a risk factor for newborn encephalopathy in term infants.

Two previously published studies of term newborn encephalopathy showed that maternal thyroid disease to be a risk factor. From these studies we identified 13 case and three control mothers with thyroid disease and investigated them further. The majority of affected case mothers had idiopathic or autoimmune hypothyroidism. Compared with control mothers, case mothers had fewer thyroid function tests in pregnancy, were more likely to remain on the same dose of medication throughout pregnancy and to have experienced other pregnancy complications. The association between maternal thyroid disease and encephalopathy may be the result of a series of different causal pathways, some of which are suggested by our data.

The continuing fall in incidence of hypoxic‐ischaemic encephalopathy in term infants

To examine trends in incidence of hypoxic-ischaemic encephalopathy in term infants over a twenty-one year period. A retrospective analysis of medical records of all term infants admitted to a neonatal unit with hypoxic-ischaemic encephalopathy during the years 1992-1996 (period C) and a comparison with data from the years 1976-1980 (period A) and 1984-1988 (period B) from the same unit (previously published). A District Health Authority in Central England serving a population of about 450,000. All term infants admitted with clinical features of hypoxic-ischaemic encephalopathy. Incidence of three grades of hypoxic-ischaemic encephalopathy, disability and mortality. In each five year period there were similar numbers of births. Over the time-span of this study the stillbirth rate and neonatal mortality rate has consistently fallen. The overall incidence of hypoxic-ischaemic encephalopathy in term infants was significantly lower (P < 0.001; OR 0.42 CI 0.29-0.59) in the present study period (C) compared with the earlier study period B (1.9 vs 4.6 per 1,000 total live births). The fall in moderately and severely affected infants between the present and the first study period was significant (1.2 vs 2.6 per 1,000 total live births, P < 0.001: OR 0.46 CI 0.29-0.72). The number of deaths and the incidence of cerebral palsy in survivors fell progressively over the 21 years spanned by this study. This study shows that the incidence of hypoxic-ischaemic encephalopathy and its sequelae in term infants has fallen significantly. The use of cardiotocography and caesarean section rates have risen but the relative contributions of changes in clinical practice are uncertain.

Newborn encephalopathy in term infants: Three approaches to population-based investigation

Epidemiological studies of abnormal neonatal neurology—newborn encephalopathy—are of value not only because of their intrinsic interest, but also because newborn encephalopathy as a potential indicator of the quality of intrapartum care needs to be evaluated. As newborn encephalopathy has a closer temporal relationship to the exposures of interest than does cerebral palsy, it would have a significant advantage over cerebral palsy as an index of intrapartum care. However, the proportion of newborn encephalopathy cases which arise in labour needs to be determined accurately before we can contemplate using the occurrence of newborn encephalopathy as such an indicator. Few good epidemiological studies of newborn encephalopathy have been carried out and there are many challenges in elucidating its antecedents. This paper reviews these challenges and briefly describes and contrasts three ongoing studies.

Predictors of neonatal encephalopathy in term infants

Predictors of neonatal encephalopathy in term infants

Falling incidence of hypoxic‐ischaemic encephalopathy in term infants

To examine trends in the incidence of hypoxic-ischaemic encephalopathy over a 13-year period. A retrospective analysis of medical records of all infants admitted in the years 1976-1980 and 1984-1988. A large non-teaching district health authority in central England. Infants admitted to a district general hospital neonatal unit with clinical features of hypoxic-ischaemic encephalopathy. Incidence of three grades of hypoxic-ischaemic encephalopathy, handicap and mortality. During the first 5-year period the overall incidence of hypoxic-ischaemic encephalopathy was 7.7 per 1000 live births with 2.6 per 1000 live births being severely affected (grades II and III). In the second 5-year period the overall incidence was 4.6 per 1000 live births with 1.8 per 1000 live births being severely affected. The difference in the overall rate is statistically significant. Of the infants with severe encephalopathy 61% had Apgar scores below 4 at 1 min and 60% were born by instrumental or operative delivery. The fall in incidence of hypoxic-ischaemic encephalopathy has occurred during a period of falling perinatal mortality rate. It was instructive to find that infants born vaginally and without obstetric intervention formed a larger fraction of the severely affected infants in the later period.

Hypoxic-ischemic encephalopathy in term infants: diagnosis and prognosis evaluated by ultrasound.

The results of cranial ultrasonography in 32 term infants who had hypoxic-ischemic encephalopathy (HIE) and in 26 control infants were reviewed. Small or nonvisualized ventricles were present in 94% of the patients with HIE and in 62% of the control subjects. In 20 of the 32 patients (63%) with HIE, ultrasound demonstrated parenchymal abnormalities; the most common finding was periventricular hyperechogenicity (12/32 patients). There was a single false positive result in the control group. Fifty per cent of patients with HIE who had abnormalities demonstrated on ultrasonograms died (within 15 days of birth), whereas none of the infants who had normal ultrasound findings died. Moreover, 80% of surviving patients who had abnormal ultrasound findings had residual neurological deficits versus only 11% of those with normal ultrasound findings. Our results indicate that ultrasound is effective in detecting parenchymal changes in patients with HIE, parenchymal echoes are a more reliable sign of HIE than ventricular size, and the finding of parenchymal lesions on ultrasound scans appears to be predictive of abnormal motor development.

Factors affecting outcome in hypoxic-ischemic encephalopathy in term infants.

Forty-nine term infants were prospectively shown to have hypoxic-ischemic encephalopathy (HIE). All infants survived the neonatal period, and all but two infants (seen at 12 months) were followed up to at least 27 months of age. Factors that significantly correlated with outcome included the Sarnat encephalopathy stage and the occurrence of intractable seizures not controlled by phenobarbital sodium alone. There was no association between the one- or five-minute Apgar score, the need for early ventilation, the EEG, the occurrence of seizures, and the subsequent outcome. There was no significant difference in outcome for those infants who received dexamethasone sodium phosphate (n = 29) v those who did not receive the drug (n = 20). A review of 97 term infants with HIE from a regional perinatal program during a one-year period (1979), including 35 of the 49 infants in the present study, did show a significant increase in morbidity and mortality for transported infants.