ANALYSIS OF CARBOHYDRATE-INTOLERANT PROFILES OF MOTHERS WITH NORMAL GLUCOSE-TOLERANCE TESTS AND THEIR LARGE FOR GESTATIONAL-AGE NEONATES

Objective: To examine endocrine states of mothers with normal 75-g ora l glucose tolerance tests (GTTs) who gave birth to large for gestation al age (LGA) neonates (group I) and to examine those neonates. Methods : We examined plasma glucose levels and serum immunoreactive insulin r esponses after the 75-g oral GTT was given to group I mothers (N = 34) , mothers with an abnormal oral GTT who gave birth to LGA neonates (gr oup II, N = 21), and those with normal oral GTTs having appropriate fo r gestational age neonates (group III, N = 173). We also examined the infants, checking neonatal birth weight, levels of immunoreactive insu lin and C-peptide immunoreactivity in cord sera at birth and the lowes t blood sugar level after birth to see if a correlation existed betwee n them. Results: Group I and II mothers showed higher titers in plasma glucose levels and remarkably enhanced ratios of 60- to 30-minute imm unoreactive insulin values (immunoreactive insulin up-ratio) after loa d compared with those of group III mothers. Cord serum immunoreactive insulin and C-peptide immunoreactivity were significantly higher and t he lowest blood sugar level was significantly reduced in group I and I I neonates compared with those in group III. We observed a positive co rrelation between cord serum immunoreactive insulin, C-peptide immunor eactivity, and birth weight, but a negative correlation between cord s erum immunoreactive insulin, birth weight, and the lowest blood sugar level in group I and II neonates (strongest tendency in group II), but not in group III neonates. Conclusion: All of the abnormal carbohydra te metabolic responses in group I mothers and neonates may result in t he promotion of growth in LGA fetuses similar to group II, but to a le sser extent. Identification of group I mothers by the immunoreactive i nsulin up-ratio after oral GTT will help predict the occurrence of LGA neonates and their possible hypoglycemia.