Newborns with transient low blood sugar may have lower literacy and math achievement test scores in fourth grade, according to researchers from Baylor College of Medicine and the University of Arkansas for Medical Sciences in a report that will appear online in the journal JAMA Pediatrics.

Using data from infants born at the University of Arkansas for Medical Sciences hospital in 1998, where all newborns have their sugar levels screened during the first three hours after birth, the team sought to determine the effect of low blood sugar level on academic achievement in fourth grade.

“Low blood sugar (specifically low glucose levels, known as hypoglycemia) is important because the newborn’s brain principally uses glucose for energy,” said Dr. Jeffrey R. Kaiser, the study’s principal investigator and a professor of pediatrics and obstetrics and gynecology at Baylor and Texas Children’s Hospital. “It is well known that persistent and very low glucose levels in newborns are associated with brain damage and poor long-term development. The general feeling among neonatologists is that one single low value doesn’t make a difference at all, but no one has actually proven that. We wanted to look into this further since we had the data,” said Kaiser.

Kaiser also stressed that the study was preliminary and the findings will have to be validated by other researchers before changes in screening and management should be made.  

In utero, the baby gets glucose from the mother through the placenta. After birth, the baby gets glucose from the mother through her milk or from formula, and the baby also produces it in the liver. Glucose levels can drop if there is too much insulin in the blood, the baby is not producing enough glucose, does not have enough glucose stores or does not get enough during breast feeding or from formula.

With the availability of the universal glucose screening data in Arkansas – from more than 30,000 infants – Kaiser and the team were able to team up with the Arkansas Department of Education and Arkansas Department of Health to match data from 1,395 infants born in 1998 with their 2008 achievement test scores (when the children were 10 years old).

Included in the study were children with normal glucose levels at birth and those with the transiently low levels. Newborns with persistently low glucose levels were excluded from the study because they are known to have worse neurodevelopment. The primary outcome of the study was proficiency on fourth grade literacy and mathematics achievement tests.

After controlling for gestational age, race, gender, socioeconomic status and maternal education, the team was able to associate early transient hypoglycemia with decreased proficiency on literacy and mathematics tests.

Babies with normal glucose levels were about 20 percent more proficient than those with transiently low glucose levels, Kaiser said. He added that this is important because lower fourth-grade achievement test scores are associated with lower high school graduation rates, less college attendance and, ultimately, less long-term economic success.

“The hope is that now that we have shown some evidence of the impact of early transient newborn hypoglycemia, and if corroborated by other researchers, maybe we will screen for it and treat it to prevent these cognitive defects,” said Kaiser.

Current recommendations about whom to screen and treat do not include otherwise healthy full-term newborns, but only those whose mothers have diabetes, babies born prematurely and those who are small or large for gestational age. Kaiser cautioned strongly that the findings need to be validated in other populations before universal newborn glucose screening should be adopted.

The data collection portion of the study was conducted while Kaiser was on faculty at the University of Arkansas for Medical Sciences. The analysis portion was conducted at Baylor and Texas Children’s following his recruitment in 2012.

Co-authors include Shasha Bai, Nahed O. El Hassan and Christopher J. Swearingen of the University of Arkansas For Medical Sciences (Dr. Swearingen is now at Samumed, LLC); Neal Gibson and Greg Holland of the University of Central Arkansas; Tsai Mei Lin of the Arkansas Department of Health, and Jennifer K. Mehl, who was a medical student at the University of Arkansas and is now a pediatric resident at Baylor.