Blood glucose determinations in large for gestational age infants.

Our purpose was to identify factors that may contribute to hypoglycemia in large for gestational age (LGA) infants and subsets of infants for whom blood glucose screening would be clinically helpful. LGA infants of 36 to 42 weeks of gestational age using the Denver criteria were identified from the 1999 through 2001 birth log at Marquette General Hospital, Marquette, Michigan, a rural referral hospital, for a retrospective chart review. Infants of mothers with diabetes were excluded. The impact of maternal factors, intrauterine factors, and birthweight on blood glucose levels was assessed using marginal mixed models, Poisson regression, and receiver operating characteristic curves. We found 457 infant records documented blood glucose levels among the 727 infant records analyzed. The lowest blood glucose levels occurred in the first 90 minutes of life. Blood glucose levels were positively associated with weeks of gestation and breastfeeding. Birthweight did not predict hypoglycemia in any of the multivariable models constructed. Symptoms consistent with hypoglycemia occurred only in boys and were negatively associated with gestational age. Models using prenatal and perinatal factors to predict hypoglycemia or symptomatic hypoglycemia had little clinical value. In this large community-based sample of LGA infants, we found no evidence that higher birthweight increases the risk for hypoglycemia. The clinical usefulness of routine blood glucose monitoring in healthy LGA infants is not supported by this retrospective analysis and needs to be established by prospective studies.