Low Blood Sugar a Marker for Babies at Neurological Risk During Delivery, NewYork-Presbyterian/Weill Cornell Study Suggests
Testing for Hypoglycemia Might Help Save Newborns
from Brain Damage, Alerting Doctors to the Danger Early On
New York, NY (September 23, 2004) — Abnormally
low blood sugar may raise an infant's risk for brain damage during delivery,
according to a new study led by a NewYork-Presbyterian Hospital/Weill Cornell
Medical Center researcher. He believes early testing for neonatal hypoglycemia
might potentially reduce neurologic morbidity.
"In full-term babies already at elevated risk for brain damage, low blood
sugar increased that risk 18-fold," said Dr. Jeffrey M. Perlman, Professor
of Pediatrics at Weill Cornell Medical College, and Chief of the Division of
Newborn Medicine at New York-Presbyterian/Weill Cornell.
His team's study is published in the journal
Pediatrics.
About 1 in every 1,000 deliveries in the U.S. ends with the newborn suffering
severe, often irreversible brain damage due to a lack of oxygenated blood flow
to the brain.
"Such babies can die, and if they survive, the long-term effects can be
devastating," Dr. Perlman said. "Usually it's severe forms of cerebral
palsy."
Unfortunately, obstetricians are still looking for a reliable method of spotting
these problem deliveries early on, when interventions might help prevent or
limit neurological damage.
Already, one factor — fetal acidemia, or a high blood acidity in the
umbilicus, related to interrupted blood flow — has been shown to be a "red
flag" for subsequent brain injury.
Dr. Perlman theorized that low levels of glucose in umbilical cord blood might
be another such marker. The reasoning is simple: "All of us, babies included,
need glucose as an energy source in the brain. If your blood sugar is low,
then your brain has a reduced energy source. It's running on — or near — empty."
In their retrospective study, Dr. Perlman and colleagues compared the blood
sugar levels and neurological outcomes of 185 full-term infants with severe
fetal acidemia, admitted to the neonatal intensive care unit at the University
of Southwestern Medical Center, Dallas, where Dr. Perlman conducted much of
the research before joining Weill Cornell.
Overall, 41 of the infants developed some form of brain damage, including 14
who died due to severe neonatal encephalopathy.
"What we found was that 27 of the 185 babies in the study had a blood sugar
level at delivery of 40 milligrams per deciliter or below — a level we
believe could raise risks for brain damage," Dr. Perlman said. "And,
indeed, among these 27 babies, 15 went on to suffer some level of neurological
injury — 56 percent."
In contrast, just 16% of the 158 babies with blood sugar over 40 mg/dL went
on to develop brain damage.
Dr. Perlman stressed that, on its own, initial blood sugar at or below 40 mg/dL
may not pose significant risk. However, hypoglycemic neonates do seem more
vulnerable to brain damage, especially those with severe fetal acidemia who
also require resuscitation during delivery. Overall, that combination of factors
raised risks for neurological damage 18-fold, the researchers found.
"This is a retrospective study," Dr. Perlman cautioned, "so more
needs to be done to determine whether it's simply that the sickest babies were
more likely to have low blood sugar, or whether, if you treated the glucose deficiency
early on after birth, you might be able to reduce subsequent brain injury."
"But the findings suggest that, in the context of other factors, we may
need to measure blood sugar earlier rather than later," he added. "The
'Holy Grail' of all this research is to develop what we call neuroprotective
strategies — to intervene quickly when we believe a neonate is at especially
high risk, limiting the damage."
Co-researchers on the study include Dr. Walid A. Salhab, Dr. Myra H. Wyckoff,
and Dr. Abbot R. Laptook — all of the University of Texas Southwestern
Medical Center, in Dallas.
Powered by Big Medium™
Contact Info