Page 71 - 16Neonatal Jaundice_compressed

Neonatal jaundice

significant association with hyperbilirubinaemia (adjusted OR 36.5, 95% CI 15.9 to 83.6) There
was also a statistically significant association when analysed by 17 micromol/litre increments on
day 1 (adjusted OR 3.1, 95% CI 2.4 to 4.1 per 17 micromol/litre). Change in bilirubin levels
between day 1 and day 2 was also found to have a statistically significant association with
hyperbilirubinaemia (adjusted OR 2.4, 95% CI 1.9 to 3.0 per 17 micromol/litre). Other factors
found to be associated with hyperbilirubinaemia were maternal blood group O (adjusted
OR 2.9, 95% CI 1.5 to 5.8), maternal age per year (adjusted OR 1.1, 95% 1.0 to 1.2), maternal
education per year (adjusted OR 0.8, 95% CI 0.7 to 0.9), and exclusive breastfeeding (adjusted
OR 0.4, 95% CI 0.2 to 0.9). [EL II]
Another prospective cohort study from the USA aimed to evaluate the predictive accuracy of
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clinical risk factors, pre-discharge bilirubin levels expressed as risk zones, and a combination of
pre-discharge bilirubin levels and additional risk factors. The study population comprised babies
managed exclusively in the well-baby nursery of an urban tertiary care hospital. Since the
population served by the hospital was predominantly black, stratified sampling was used to
obtain a representative sample. The study included 812 term and near-term healthy newborns
managed exclusively in the well-baby nursery with gestational age ≥ 36 weeks and birthweight
≥ 2000 g, or gestational age ≥ 35 weeks and birthweight ≥ 2500 g. About 7% of babies were
lost to follow-up and, of the remaining babies, 6.4% (48 of 751) developed significant
hyperbilirubinaemia (day 3–5 serum bilirubin or transcutaneous bilirubin levels exceeding or
within 17 micromol/litre of the hour-specific phototherapy treatment thresholds recommended
by the AAP). Using univariate analysis, the factors that were statistically associated with the
development of significant hyperbilirubinaemia (at P < 0.05) were pre-discharge bilirubin in
the high and high–intermediate risk zones, gestational age < 38 weeks, mother’s intention to
breastfeed, either exclusively or combined with bottle-feeds, grade 4 or higher jaundice
observed clinically as per the Kramer scale (only for non-black babies), vacuum delivery and
female sex. When all these factors were added in a step-wise logistic regression model (except
the pre-discharge bilirubin risk zones), only five factors were found to be independently
associated with significant hyperbilirubinaemia: gestational age < 38 weeks (OR 19, 95% CI
6.3 to 56), mother’s intention exclusively to breastfeed (OR 3.7, 95% CI 1.1 to 13), black race
(OR 0.22, 95% CI 0.08 to 0.61), grade 4 or higher jaundice observed clinically (OR 1.7, 95% CI
1.2 to 2.6), and female sex (OR 3.2, 95% CI 1.2 to 8.4). [EL II]

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In another nested case–control study from Israel, data were collected retrospectively from the
charts of 10 122 term singleton babies born at a tertiary hospital over a 4 year period. Bilirubin
levels were routinely measured in all clinically jaundiced newborns and all mothers were
interviewed within 48 hours of delivery. A total of 1154 term babies (11.4%) who developed
serum bilirubin levels ≥ 221 micromol/litre constituted the test group, while, from the
remainder, every tenth admission with serum bilirubin levels < 221 micromol/litre was
randomly selected to form the comparison group (n = 1154). Univariate analysis was done to
compare the two groups and it showed high serum bilirubin levels to be statistically significantly
associated with a number of maternal, baby and delivery variables. These variables were then
included in a step-wise logistic regression analysis and the final model revealed six factors to be
independently associated with development of high serum bilirubin levels. These factors were
maternal age > 35 years (adjusted OR 1.7, 95% CI 1.3 to 2.3), male sex (adjusted OR 1.4,
95% CI 1.2 to 1.7), primiparity (adjusted OR 2.7, 95% CI 2.1 to 3.5), previous sibling with
jaundice (adjusted OR 2.3, 95% CI 1.9 to 2.8), early gestation (for 37 weeks adjusted OR 4.5,
95% CI 3.2 to 6.3; for 38 weeks adjusted OR 2.1, 95% CI 1.6 to 2.8), and vacuum extraction
(adjusted OR 3.0, 95% CI 2.1 to 4.4). [EL II]
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In a retrospective study from the USA, the risk of recurrence of hyperbilirubinaemia in siblings
was studied in 3301 offspring of 1669 male US Army veterans participating in a nationwide
study of veterans’ health. Babies who had a different mother’s name from the rest of the sibling
relationship (paternal half-siblings), stillbirths, and babies with records showing evidence of
haemolytic disease of newborns were excluded. In case of a twin delivery (n = 34), only one
baby was randomly included for the study. Birth details of each baby were obtained by
interviews and detailed information extracted from hospital medical records by trained staff.
Hyperbilirubinaemia (defined as peak serum bilirubin levels ≥ 205 micromol/litre) was present
in 4.5% of the babies (147 of 3301). Newborns who had one or more prior siblings with

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