HYPERINSULINISM, NEONATAL OBESITY AND PLACENTAL IMMATURITY IN INFANTSBORN TO WOMEN WITH ONE ABNORMAL GLUCOSE-TOLERANCE TEST VALUE

Several groups have reported a risk of fetal macrosomia in pregnancies with maternal glucose intolerance which is intermediate between gesta tional diabetes (GDM) and normal glucose tolerance. The present study was designed to determine whether these pregnancies are also a risk fo r fetal obesity, hyperinsulinism and placental villous immaturity. 325 women with risk factors for GDM underwent a 75 g OGTT interpreted acc ording to the O'Sullivan criteria. All women who met the criteria for GDM were managed with diet therapy. Insulin therapy was added for wome n with a mean serum glucose value > 100 mg/dl on a 24 hour glucose pro file. Patients not meeting the GDM criteria were managed without speci al intervention. Primary outcome variables were measures of neonatal w eight and skinfold thickness, fetal and neonatal insulin and glucose c oncentration, and placental villous maturation. Outcome parameters wer e compared among three groups: pregnancies with normal OGTT (control, n = 95), 1 abnormal value in the OGTT (1 abnl, n - 76) and GDM (n - 15 4). The outcome of pregnancies with 1 abnormal value in the OGTT was d ifferent from those with normal OGTT. Regarding fetal growth, rates of LGA were approximately twice as high in groups with one abnormal valu e and GDM (21% and 24%) compared to women with normal OGTTs (11%: p < 0.05 vs GDM and p = 0.07 vs 1 abnormal value). The percent of infants with skinfold thickness > 90th percentile was also greater in the 1 ab normal value and GDM groups (31.1 and 31.6% respectively) compared to controls (19.2%; p < 0.05 for GDM vs control only). Regarding fetal hy perinsulinism, AFI concentrations were similar in control and GDM grou ps (3.1 +/- 0.4 and 3.4 +/- 0.8 mu U/ml, respectively), but were highe r in the group with one abnormal OGTT value (4.3 +/- 1.2 mu U/ml, p < 0.05 vs controls). Cord blood insulin: glucose ratios were elevated in both the 1 abnormal value and GDM groups (0.22 +/- 0.05 and 0.20 +/- 0.02 mu U/ml per mg/dl), compared to controls (0.12 +/- 0.01 mu U/ml p er mg/dl, p < 0.05 vs 1 abnormal value). Neonatal glycemia < 30 mg/dl was significantly more common in the one abnormal value than in the co ntrol group (49% vs 34% of infants) and intermediate in the GDM group (40%). Severe placental villous immaturity was more than twice as freq uent in the 1 abnormal value group compared to controls (24% vs 9%, p < 0.05) and the most frequent in the GDM group (33%; p < 0.001 vs cont rols). Pregnancies with glucose intolerance below the thresholds for d iagnosis of GDM have an increased risk for fetal obesity, hyperinsulin ism, postpartum hypoglycemia and placental immaturity. These findings indicate the continuum of risk for fetal morbidity associated with inc reasing maternal glucose intolerance in pregnancy.