Aim of this study was to examine the maternal-neonatal outcome and the neonatal anthropometric characteristics of a full-term mother-infant pairs group with a positive oral glucose challenge test (GCT) without gestational diabetes mellitus (GDM). Our study involved 1615 white women with singleton pregnancies who underwent universal screening for GDM in two periods of pregnancy. This population was divided into three groups according to GCT results: 1) 172 patients with abnormal GCT in both periods; 2) 391 patient with normal GCT in the early period and abnormal GCT in the late period; 3) 1052 patients with normal GCT in both periods (control group). The incidence of LGA (large for gestational age) infants was higher in Group (40.7%) and Group 2 (22.0%) respect to control group (8.3%) (p < 0.00001 and p < 0.0001 respectively) and was significantly different in the two groups (p < 0.0008). Comparison among the three groups of LGA infants showed the following results: male and female newborns of Group I were heavier than those of Group 2 and of the control group, while males and females of the control group had significantly greater length and cranial circumference means. A significant decrease in ponderal index, choracic circumference, weight/length ratio means could be seen as well as a significative increase in cranial/thoracic circumference ratio means from Group I to the control group. These data confirm the involvement of fetal development in terms of weight and anthropometric characteristics in the presence of alterations in maternal glucose metabolism which are not currently classified as gestational diabetes.