White's classification of diabetes in pregnancy in the 21st century: is it still valid?

White's classification system (WCS) was created 60 years ago to identify diabetic (DM) pregnancies at increased risk for perinatal morbidity and mortality. Our objective was to assess the association between WCS and adverse pregnancy outcome (APO) in contemporary DM pregnancies. We studied diabetic women with singleton pregnancies who delivered at >20 weeks at a single institution over a 1-year period (2007 to 2008). Perinatal outcomes were compared between WCS groups. APO was defined as any of the following: preterm birth <34 weeks, severe preeclampsia, shoulder dystocia, and neonatal respiratory disease. Presence of vascular disease was defined as presence of chronic hypertension, chronic renal insufficiency, retinopathy, coronary artery disease, or prior cerebrovascular event. One hundred ninety-six DM pregnancies met the criteria. No significant differences in APO existed between White's class groups among women with pregestational DM (32.7% class B versus 26.9% class C versus 57.1% class D to F; p = 0.46). Logistic regression revealed that vascular disease was associated with APO (odds ratio = 2.7, 95% confidence interval = 1.2 to 6.2). In our population, presence of vascular disease, rather than WCS, was a better predictor of APO in DM women.