Delayed onset of regular respiration and subsequent development

Resuscitation at birth and cognition at 8 years of age: a cohort study

BACKGROUND

Mild cerebral injury might cause subtle defects in cognitive function that are only detectable as the child grows older. Our aim was to determine whether infants receiving resuscitation after birth, but with no symptoms of encephalopathy, have reduced intelligence quotient (IQ) scores in childhood.

METHODS

Three groups of infants were selected from the Avon Longitudinal Study of Parents and Children: infants who were resuscitated at birth but were asymptomatic for encephalopathy and had no further neonatal care (n=815), those who were resuscitated and had neonatal care for symptoms of encephalopathy (n=58), and the reference group who were not resuscitated, were asymptomatic for encephalopathy, and had no further neonatal care (n=10 609). Cognitive function was assessed at a mean age of 8.6 years (SD 0.33); a low IQ score was defined as less than 80. IQ scores were obtained for 5953 children with a shortened version of the Weschler intelligence scale for children (WISC-III), the remaining 5529 were non-responders. All children did not complete all parts of the test, and therefore multiplied IQ values comparable to the full-scale test were only available for 5887 children. Results were adjusted for clinical and social covariates. Chained equations were used to impute missing values of covariates.

FINDINGS

In the main analysis at 8 years of age (n=5887), increased risk of a low IQ score was recorded in both resuscitated infants asymptomatic for encephalopathy (odds ratio 1.65 [95% CI 1.13-2.43]) and those with symptoms of encephalopathy (6.22 [1.57-24.65]). However, the population of asymptomatic infants was larger than that of infants with encephalopathy, and therefore the population attributable risk fraction for an IQ score that might be attributable to the need for resuscitation at birth was 3.4% (95% CI 0.5-6.3) for asymptomatic infants and 1.2% (0.2-2.2) for those who developed encephalopathy.

INTERPRETATION

Infants who were resuscitated had increased risk of a low IQ score, even if they remained healthy during the neonatal period. Resuscitated infants asymptomatic for encephalopathy might result in a larger proportion of adults with low IQs than do those who develop neurological symptoms consistent with encephalopathy.

FUNDING

Wellcome Trust.

Pregnancy and birth risk factors for intellectual disability in South Australia

It is generally accepted that developmental handicaps can often be minimized through early detection and intervention. For this reason, it is normal practice in many hospitals to follow-up and screen infants who present at birth with established risk factors. Clinical judgement will always be important when selecting children for follow-up. However, as hospital data systems improve, automated systems could be developed for listing children potentially "at risk". Where initial clinical decisions not to follow-up individual children prove to be at odds with this automated output, the individual child could be re-assessed clinically. This process could increase the level of quality control. An initial risk-factor model for intellectual disability has been developed, based on the South Australian Perinatal Statistics Collection, for use in this context.

Neonatal respiratory depression and delay in diagnosis in Prader-Willi syndrome

The authors retrospectively evaluated the diagnoses at four months of age for 48 individuals with known Prader-Willi syndrome. 15 had been diagnosed as having cerebral palsy, and at four months only two of the 48 had been correctly diagnosed as Prader-Willi syndrome. 11 (23 per cent) had had birth asphyxia, compared with an expected rate of 1 per cent. Other perinatal features which occurred more frequently than expected included breech presentation, decreased fetal movements and prolonged gestation. Failure to make an early diagnosis of Prader-Willi syndrome often results in later disability being blamed on the birth process, when instead the child's neonatal problems are secondary to a prenatal condition.

Antecedents of cerebral palsy. Multivariate analysis of risk

We examined prenatal and perinatal factors predicting cerebral palsy, using multivariate analysis to investigate which factors were most important and the proportion of cases for which they accounted. Maternal mental retardation, birth weight below 2001 g, and fetal malformation were among the leading predictors. Breech presentation was also a predictor, but breech delivery was not. A third of the children with cerebral palsy who had breech presentations had a major noncerebral malformation. Among 189 children with cerebral palsy, 40 (21 percent) had at least one of three clinical markers suggestive of asphyxia; only 17 of these 40 children (9 percent of all cases) lacked major congenital malformation or other intrinsic defects that might have contributed to an unfavorable outcome. When all the principal risk factors present by the time labor began were considered, the 5 percent of the population at highest estimated risk was seen to have contributed 34 percent of the cases. When all the risk factors present during the period beginning before pregnancy and extending through the nursery stay were included, the 5 percent at highest risk was seen to have contributed 37 percent of the cases. Thus, the inclusion of information about the events of birth and the neonatal period accounted for a proportion of cerebral palsy only slightly higher than that accounted for when consideration was limited to characteristics identified before labor began.

Apgar score, meconium and acidaemia at birth in relation to neonatal neurological morbidity in term infants

The relation between Apgar score, meconium and acidaemia at birth and neonatal neurological morbidity was investigated in 805 vaginally born term infants whose birthweight was appropriate-for-dates (AFD). Presence or absence of meconium stained amniotic fluid was not related to the neonatal neurological condition. The 1-min and 3-min Apgar scores and the umbilical artery pH were related, but the variances explained in neonatal neurological optimality score were very low (0.9 and 0.5% respectively). Combination of Apgar score and pH slightly increased these percentages to 1.5. The highest frequency of neurologically deviant infants was, on the other hand, found in the group with a normal pH but low Apgar score. It is concluded that in AFD term infants nowadays the predictive value of a low Apgar score, acidaemia at birth and/or presence of meconium for the neonatal neurological morbidity is poor. Most neonatal neurological abnormalities must be due to other factors.

Nucleotide sequence of a gene from chromosome 1D of wheat encoding a HMW-glutenin subunit

A high molecular weight glutenin gene in hexaploid wheat has been isolated by cloning in bacteriophage lambda and characterized. The gene corresponds to polypeptide 12 encoded by chromosome 1D in the variety "Chinese Spring". The coding sequence predicted contains seven cysteine residues six of which flank a central repetitive region comprising more than 70% of the polypeptide. These findings are related to the role of high molecular weight subunits in the viscoelastic theory of gluten structure.

The relation between umbilical pH values and neonatal neurological morbidity in full term appropriate-for-dates infants

The relationship of umbilical cord pH with the neonatal neurological condition was investigated in a group of 805 appropriate-for-dates (AFD) infants, delivered vaginally at term, and in a subgroup of 205 infants born after uncomplicated pregnancy and delivery ('low-risk' group). The results of the neonatal neurological examination were expressed in a neonatal neurological optimality score (NNOS) and in a neurological classification (normal, suspect and abnormal). In both study groups a significant relation between umbilical arterial pH (pHua) and the difference between maternal venous pH and pHua (delta pHm-ua) on the one hand and neurologically suspect infants and NNOS on the other hand, was found. The percentages of explained variance in NNOS, however, were very low (for delta pH, 1 and 4% in the total and low-risk group respectively). Neurological abnormality was not related to acidaemia at birth. Because of the specific relation between maternal and umbilical pH, delta pH is a less reliable indicator of fetal condition in cases of maternal alkalosis or acidosis. The use of a delta pH corrected with the help of a maternal-fetal pH nomogram, however, only slightly improved the relation with neurological morbidity. It is concluded, that in AFD term infants acidaemia at birth is only slightly related to neonatal neurological morbidity.