The frequency of hypoglycemia in full-term large and small for gestational age newborns.

Although various authors recommend screening for hypoglycemia in large for gestational age (LGA) and small for gestational age (SGA) newborns, the frequency of hypoglycemia in these infants, using a recent definition of hypoglycemia, and the proper duration of screening are not documented. We determined chromogen test strip blood glucose values at ages 1, 2, 3, 6, 12, 24, 36, and 48 hours in full-term LGA and SGA infants whose mothers were not diabetic. Serum glucose determination was immediately done if a test strip reading was less than 40 mg/dl. Hypoglycemia was defined as a serum glucose less than 35 mg/dl at less than 3 hours of age, less than 40 mg/dl at 3 to 24 hours of age, and less than 45 mg/dl at more than 24 hours of age. The frequency of hypoglycemia in LGA infants was 8.1% (95% confidence interval [CI] 5.0 to 11.2%), and in SGA infants, 14.7% (95% CI 9.8 to 19.6%). The mean age at which hypoglycemia occurred was 2.9 hours (range, 0.8 to 8.5) in LGA infants, and 6.1 hours (range, 0.8 to 34.2) in SGA infants. There were no differences in other possible risk factors between the hypoglycemic and euglycemic infants except that in SGA infants meconium-stained amniotic fluid (40% vs 20%, p = .001), maternal preeclampsia (27% vs 8%, p = 0.0056), and male sex (29% vs 9%, p = 0.029) were more common in hypoglycemic than in euglycemic infants. These data suggest that screening for hypoglycemia in LGA infants whose mothers are not diabetic may be stopped after 12 hours, but should continue for 48 hours in SGA infants.