FASTING PLASMA-GLUCOSE AND GLYCOSYLATED PLASMA-PROTEIN AT 24 TO 28 WEEKS OF GESTATION PREDICT MACROSOMIA IN THE GENERAL OBSTETRIC POPULATION

The purpose of this study was to modify the traditional gestational di abetes screening process in order to provide a test that might more re liably detect those women at risk of delivering a macrosomic infant de spite a negative test for gestational diabetes mellitus (GDM). Pregnan t women (n = 160) were screened for GDM at 24 to 28 weeks' gestation u sing the traditional 50 g glucose challenge test (GCT). In addition, g lycosylated hemoglobin, glycosylated serum protein, and glycosylated p lasma protein (CPP) were analyzed from blood drawn at th is same time. if the patient's challenge test was positive (140 mg/dL or higher), a 100 g oral glucose tolerance test (OGTT) was performed. Twenty-three women had a positive GCT (14.4%) and five (3.13%) were excluded from f urther study because they received treatment for gestational diabetes based on a positive OCTT. None of the CCT-negative or the GCT-positive -OGTT-negative patients received treatment. Gestation al age at delive ry, infant gender, and birthweight were retrieved from birth records. Although several correlations with infant birthweight were found, the fasting plasma glucose (FPG) and GPPs proved most significant. The FPG on the OGTT significantly correlated with infant birthweight (p <0.00 1; r = 0.94). A value greater than 90 mg/dL proved to be 100% sensitiv e and 64% specific for infant birthweight more than 4000 g. The relati onship of the GPP and subsequent infant birthweight was also significa nt (p <0.001; r = 0.81). A GPP greater than 23% proved to be 100% sens itive in predicting birthweight above 4000 g (11 of 11 infants); howev er, the test had a 52% specificity Partial correlation coefficients th at take into account the interdependence of response revealed that eac h independently predicted infant birthweight. Using a combination of a GPP above 23% and a FPG above 90 mg/dL resulted in 100% sensitivity a nd 93% specificity for an infant greater than 4000 g. This study indic ates that women at risk for delivery of a macrosomic infant may be ide ntified at 24 to 28 weeks' gestation by measurement of FPG and CPP.