Readily available risk factors can help predict neonatal hyperbilirubinemia

Last Updated: 2015-11-10

By Larry Hand

NEW YORK (Reuters Health) - Collecting readily available maternal and obstetric risk factors can help predict neonatal hyperbilirubinemia, according to new research.

"This large, population-based study from Sweden shows that collection of a few - already at birth easily available - maternal and obstetric risk factors predicts a more than 100-fold variation in the incidence of neonatal hyperbilirubinemia in need of treatment," Dr. Mikael Norman, of Karolinska Institute and University Hospital in Stockholm, told Reuters Health by email.

Dr. Norman and colleagues analyzed data from the Swedish Medical Birth Register from 1999 to 2012. Of more than 1.2 million singleton infants, 23,711 had diagnoses of hyperbilirubinemia after exclusion of hemolytic newborn diseases.

They found that risk factors with adjusted odds ratio for neonatal hyperbilirubinemia of 1.5 or greater included gestational age 37-38 weeks (aOR, 2.83), failed vacuum extraction (aOR, 2.79), vacuum extraction (aOR, 2.22), Asian mother (aOR, 2.09), primiparous mother (aOR, 2.06), large for gestational age (LGA, aOR, 1.84), obese mother (aOR, 1.83), and small for gestational age (SGA, aOR, 1.66).

"The study confirms some previously known risk factors (gestational age 37 weeks, Asian mother, vacuum extraction, LGA-infant), disregards other previously suggested risk factors (diabetic mother, advanced maternal age, male sex), and identifies some new risk factors (primiparous mother, obese mother, SGA-infant) for neonatal hyperbilirubinemia in need of treatment," Dr. Norman said.

The researchers found the rate of nonhemolytic neonatal hyperbilirubinemia to be 0.7% for normal birth weight infants delivered vaginally at 39-41 weeks gestation by a non-Asian, non-obese, multiparous mother. Overall, rates ranged from 0.2% to 25%.

They also found that planned Cesarean delivery was associated with reduced risk (aOR, 0.45).

"Some newborn infants, also in the absence of hemolytic or other diseases, show a pronounced imbalance between bilirubin production and excretion, resulting in excessive bilirubin levels. High levels of unconjugated bilirubin could be associated with brain dysfunction and even permanent brain damage," Dr. Norman told Reuters Health.

"The size of the study enabled the construction of a score sheet for individualized risk prediction with interactions between different risk factors taken into account," he added. "This new information may be a good starting point for parental counseling and for professional decision-making on additional management in the neonatal period, especially for families leaving hospital very early after delivery."

"The proposed sheet of hyperbilirubinemia prediction based on risk factors should optimally be cross-validated," he said. "We see two possibilities for future validation: to perform a similar study to ours using a sufficiently large data set generated in another country or population or to use the proposed prediction sheet and prospectively study to what extent the prediction of significant hyperbilirubinemia mirrors the outcome."

He added, "Successful hyperbilirubinemia prediction and kernicterus prevention build on a systems approach in which risk assessment after birth must be combined with other actions in the neonatal period."

SOURCE: http://bit.ly/1Qp5yyJ

Pediatrics 2015.