Evaluating the therapeutic approach in pregnancies complicated by borderline glucose intolerance: a randomized clinical trial

Abstract

Most studies relating minor gestational metabolic alterations to macrosomia refer to glucose intolerance classified on the basis of the National Diabetes Data Group or previous World Health Organization diagnostic thresholds. Our aim was to evaluate the consequences of very mild forms of gestational glucose intolerance, defined by an elevated 50-g glucose challenge test followed by a normal oral glucose tolerance test, using the more restrictive Carpenter and Coustan's criteria (Borderline Gestational Glucose Intolerance, BGGI). Three hundred BGGI women were randomly assigned to: Group A (standard management), Group B (dietary treatment and regular monitoring). A control group (C) was also considered. Newborns were classified as macrosomic, large (LGA), or small for gestational age (SGA). The three groups were similar in age, body mass index and parity. Therapy in Group B significantly improved fasting (from 4.68 +/- 0.45 to 4.28 +/- 0.45 mmol/l) and 2-h postprandial glycaemia (from 6.01 +/- 0.57 to 5.13 +/- 0.68 mmol/l). Fasting glycaemia at delivery was significantly lower in B (4.20 +/- 0.38 mmol/l) than in A (4.84 +/- 0.45 mmol/l), and was also lower than in C (4.31 +/- 0.39 mmol/l). Significantly fewer LGA babies were born to Group B (6.0%) than Group A (14.0%) and Group C (9.1%). No difference was found in the SGA rate. The neonatal Ponderal Index was higher (P = 0.030) in group A (2.73 +/- 0.35) than in C (2.64 +/- 0.30) and B (2.64 +/- 0.24). Even very mild alterations in glucose tolerance can result in excessive or disharmonious fetal growth, which may be prevented by simple, non-invasive therapeutic measures.