Page 75 - 16Neonatal Jaundice_compressed

Neonatal jaundice

In a retrospective matched case–control study from a university hospital in the USA, all babies
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showing kernicterus at autopsy during a 6 year period were classified as cases (n = 32) while
babies without kernicterus at autopsy constituted the control group (n = 32). Both groups were
matched for the year of birth, gestational age, birthweight, and duration of survival. Data on
multiple clinical, historical and laboratory variables were derived from hospital records.
Gestational age ranged from 25 to 41 weeks with a mean gestational age of 31 weeks for both
the groups, while birthweight ranged between 750 and 5000 g (mean 1800 g). Variables
evaluated included maternal gravidity, maternal age, 1 minute Apgar scores, lowest
haematocrit, lowest pH, average pH, hypoxia, peak serum bilirubin, hypercarbia and lowest
temperature. There was no statistically significant difference between the cases and the controls
for any of the variables evaluated on univariate or multivariate analysis. Multivariate analysis
also failed to determine any factor that was statistically significant. [EL II]
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A retrospective study from the USA compared clinical and demographic histories of late
preterm babies who suffered kernicterus with those of affected term babies, all of whom were
entered in the Pilot Kernicterus Registry. Babies were included if they had been discharged well
after birth and subsequently suffered kernicterus. A total of 125 of the 142 cases reported to the
Registry met the inclusion criteria. The mean birthweight of the study population was 3281 g
and the mean gestational age was 38 weeks. Mortality among cases was 4.8%. The total serum
bilirubin levels, age at re-hospitalisation, and birthweight distribution were similar for the late
preterm (34 to < 37 weeks, n = 29) and the term babies (> 37 weeks, n = 96). More late
preterm babies developed kernicterus as compared with term babies (38% versus 25%;
P < 0.05). Similarly, severe post-icteric sequelae occurred in 83% of the late preterm babies
compared with 71% in the term babies. The percentage of large for gestational age babies
among the late preterm group who developed kernicterus was statistically significantly higher
compared with that in the term group (34.9% versus 24.7%; P < 0.01). [EL III]

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A multicentre prospective cohort study from the USA examined the association between
serum bilirubin concentration and neurodevelopmental outcomes. The study population
included first- born white and black singleton babies with birthweight ≥ 2500 g who survived
for at least 1 year and had at least one bilirubin measurement recorded (n = 41 324). Each baby
had serum bilirubin measured between 36 and 60 hours of age (as close to 48 hours as possible)
and subsequent sampling was done on clinical grounds. The outcomes evaluated were
intelligence quotient (IQ) assessment by psychologists (using Wechsler Intelligence Scale for
Children) at the age of 7 years, blinded neurological examination by paediatric neurologists or
other trained clinicians at the age of 7 years, and hearing evaluation performed at 8 years of age
using pure-tone audiometry. Multiple logistic regression analysis was performed to control for
potential confounding variables (maternal education level, parity, feeding method during
nursery stay, oxytocin use, birthweight, maternal age). The study also looked for variables (race,
gender, gestational age, DAT result, exchange transfusion) that could act as effect modifiers for
the relationship between bilirubin levels and the defined outcomes. Follow-up data were
available for 80% of the study population. About 1% of the white babies (n = 21 375) had peak
serum bilirubin level ≥ 342 micromol/litre while the proportion among the black babies
(n = 19 949) was 0.6%. No statistically significant association was seen between high serum
bilirubin levels and IQ scores or sensorineural hearing loss. Abnormal neurological examination
was reported more commonly in children with high serum bilirubin levels
(≥ 342 micromol/litre) compared with those with lower serum bilirubin levels, but the
difference was statistically not significant (4.5% versus 3.8%; RR 1.2, 95% CI 0.7 to 2.1).
However, it was observed that there was a statistically significant linear increase in the risk of
‘suspicious’ abnormal neurological examination with an increase in the serum bilirubin levels
(OR 1.12, 95% CI 1.06 to 1.2). This association was not statistically significant when serum
bilirubin levels were analysed as a dichotomous variable. Sensorineural hearing loss was not
associated with high bilirubin levels, but only 50% of study participants had undergone hearing
evaluation. [EL II]
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A prospective cohort study conducted in a university hospital neonatal unit in Malaysia
evaluated the risk factors associated with hearing loss in term babies with serum bilirubin levels
> 339 micromol/litre. The study included 128 jaundiced term babies with a mean age of
jaundice onset being 3.4 days. Babies with congenital anomalies and those receiving

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