Gestational diabetes mellitus - an analysis of risk factors.

INTRODUCTION: Gestational diabetes mellitus (GDM) is associated with an increased frequency of gestational, perinatal and neonatal complications. The aim of the study was to evaluate risk factors for GDM and their predictive value.

MATERIAL AND METHODS: The group studied consisted of 510 pregnant women with GDM diagnosed according to World Health Organization (WHO) criteria (GDM). The controls were 1160 pregnant women with normal glucose tolerance (NGT). Multifactorial analysis was performed and odds ratios (OR) were calculated for each risk factor identified.

RESULTS: The GDM patients were significantly older than the NGT subjects (30.1 vs. 27.2 years; p < 0.0001), had a greater tendency towards obesity before pregnancy (BMI 25.0 vs. 21.6 kg/m2; p < 0.0001), more often had relatives with diabetes (40.0 vs. 25.7%; p < 0.01), had greater parity (third or subsequent pregnancy: 33.6 vs. 16.0%; p < 0.001) and more often experienced adverse perinatal outcomes (21.4 vs. 13.7%; p < 0.01). Multivariate analysis revealed the following risk factors for GDM: BMI > 25 kg/m2 (OR 4.14), a history of macrosomia (OR 2.72), being pregnant for the third time or more (OR 1.8), a family history of diabetes (OR 1.76) and age at gestation > 25 years (OR 1.34). No risk factors were present in 12% of GDM subjects, and at least one risk factor was found in 74.1% of subjects with NGT. No risk factor cluster was found which could be used easily in everyday practice to identify reliably subjects at increased risk of GDM.

CONCLUSIONS: Age, overweight and obesity, diabetes in the family, parity, macrosomia and a history of perinatal complications were identified as risk factors for GDM. As no reliable method of identifying subjects at increased GDM risk was found, we suggest that all pregnant women should undergo laboratory screening for GDM.