Factors predictive of recurrent gestational diabetes diagnosed before 24 weeks' gestation.

The purpose of this study was to determine which patient and pregnancy characteristics in the first pregnancy complicated by gestational diabetes mellitus (GDM) were associated with the diagnosis of GDM before 24 weeks' gestation in a subsequent pregnancy--early recurrent GDM. The case notes of 180 women who previously had GDM diagnosed and who had glucose tolerance tests performed before 24 weeks' gestation in their next ongoing pregnancy were reviewed. Factors examined included severity of GDM, insulin requirement, racial origin, macrosomia, obesity, age, family history of diabetes, preeclampsia, and parity. Multivariate analysis showed that women with early recurrent GDM were more likely, in their first pregnancy with GDM, to have needed insulin (odds ratio [OR] 11.26; 95% confidence interval [CI] 2.02 to 62.65), to be more often of non-Northern European origin (OR, 5.53; 95% CI, 2.46 to 12.44), to have had a macrosomic infant (OR, 4.01; 95% CI, 1.40 to 11.49) or severe GDM (OR, 3.52; 95% CI, 1.60 to 7.76), and were more often 30 years or more of age (OR, 2.27; 95% CI, 1.05 to 4.90). Obesity, family history, fasting plasma glucose levels, and parity were not significant risk factors. However, even without any of the significant risk factors, logistic regression modeling suggested that a woman who has had GDM in a previous pregnancy has a 5.1% (95% CI, 2.2 to 11.6%) chance of having early recurrent GDM. We therefore continue to recommend that all women who have had GDM diagnosed previously should have glucose tolerance testing performed early (before 24 weeks' gestation) in any future pregnancies.