Before birth, babies receive a steady stream of glucose from their mothers through the placenta. After birth, a newborn begins to regulate his own glucose production. In the first few hours after birth, the blood glucose level may fall but then begin to stabilize. Babies with increased glucose demands or those who have difficulty regulating their glucose levels may develop hypoglycemia, or low blood sugar. Around two out of 1,000 babies develop neonatal hypoglycemia, which can cause serious brain damage if untreated, according to Children's Hospital Boston. Hyperglycemia, or high blood glucose, occurs less frequently.
Definition
A newborn's blood glucose levels should remain above 40 milligrams per deciliter, or mg/dL. Levels below 35 mg/dL indicate severe hypoglycemia, while levels under 50 mg/dL warrant close observation. A level between 54 and 72 mg/dL indicates a more normal newborn blood glucose, states Rhishikesh Thakre, M.D., on the website Neo Clinic. At-risk infants need blood glucose monitoring within the first two hours after birth.
Causes
Infant at high risk for hypoglycemia include those whose mothers had diabetes during pregnancy, premature infants, babies with intrauterine growth retardation and sick infants, who have higher glucose needs than healthy infants. Infants who aren't kept warm enough can develop cold stress, which can lead to hypoglycemia. Infants with congenital diseases, such as hypothyroidism, congenital heart disease or brain damage, or infants who suffered from lack of oxygen at birth may also develop hypoglycemia.
Symptoms
Hypoglycemic newborns may have no symptoms. Symptoms of neonatal hypoglycemia include jitteriness or tremors, poor feeding, lethargy, decreased muscle tone or floppiness, and irritability. If hypoglycemia progresses, the baby may stop breathing for short periods, a condition known as apnea, turn blue or cyanotic from lack of oxygen, or have seizures. Coma and death can follow.
Treatment
If the baby can eat and the blood glucose level is not too low, giving formula, sugar water or breast milk will raise blood glucose levels in most cases. Babies who can't eat or those with very low blood glucose levels need intravenous infusion of dextrose, a type of sugar, to raise their blood sugar. Infants receiving glucose infusions may develop temporary hyperglycemia, or blood glucose levels over 125 mg/dL, which usually requires no treatment, according to See Wai Chan, M.D., assistant professor of pediatrics at Houston Medical Center on the physician-authored website UpToDate.
Prevention
At-risk infants require blood glucose screening via heel stick or from blood drawn from a central umbilical line. The baby may need frequent blood tests in the first 12 hours after birth to ensure that levels don't drop. Hypoglycemia most often develops within the first 24 hours after birth, Dr. Thakre states.
