Objective: To evaluate in a selected population the clinical characteristics (time of diagnosis, different treatment, metabolic parameters, etc.) of gestational diabetes in relation to prepregnancy body mass index (BMI) and the influence of BMI on neonatal outcome.
Design: This study was retrospectively led using a computerized data system for all deliveries that occurred at the Departments of Obstetrics and Gynecology of the University of Pisa (Italy) from 1 January 1987 to 31 December 1992.
Subjects: 93 women with GDM and 110 control subjects divided into three groups according to their pre-pregnancy BMI: normal weight (Nw), overweight (Ow) and obese (Ob).
Measurements: Time of diagnosis, mode of treatment and metabolic control of GDM; time and mode of delivery, neonatal outcome (macrosomia, respiratory distress syndrome, hyperbilirubinemia, hypoglycemia, polycythemia, hypocalcemia).
Results: GDM was diagnosed earlier in Ow and Ob than in Nw (p < 0.01) and insulin treatment was used in 86% of Ob-GDM, 91% of Ow-GDM and in 77% of Nw-GDM women (p < 0.001). Preterm deliveries and cesarean sections resulted significantly increased in all BMI categories of GDM patients with respect to matched normal controls. Prevalence of neonatal macrosomia was higher in GDM patients (44.6%) compared with normal controls (15.4%) and correlated (p > 0.01) with prepregnancy BMI in both groups. The body weight increase during pregnancy was not associated with neonatal macrosomia.
Conclusions: The degree of overweight is associated with an earlier diagnosis of GDM; prepregnancy BMI is more predictive of macrosomia than weight gain, both in control and GDM women; GDM seems to play the most important role in increasing the possibility of the occurrence of macrosomia.