Risk factors for early post-partum diabetes in women with recent gestational diabetes

Purpose: A postpartum oral glucose tolerance test (OGTT) is recommended in all women with recent gestational diabetes (GDM), but is performed in only 50% of the women. Our purpose was to determine maternal and neonatal risk f actors associated with persisting diabetes early postpartum in women with r ecent GDM. Study design: 1654 women with diagnosis of GDM in the recent pregnancy unde rwent a 75 g 2 hr OGTT 4-16 weeks postpartum interpreted by NDDG criteria. Maternal demographic and glycemic parameters (DM screening, fasting and pos t-challenge glucose and the area under the curve [AUC] of the diagnostic OG TT, highest fasting), and neonatal outcome parameters (birth weight, body m ass index, major malformations, stillbirth) were tested by univariate and m ultivariate logistic regression for their predictive risk of a diabetic pos tpartum OGTT. For continuous variables the relative risk for DM was additio nally compared between the highest and lowest quartile of the cohort. Results: Postpartum diabetes was diagnosed in 218 (13.2%), impaired glucose tolerance in 199 (12.0%) women. Several maternal demographic and all glyce mic parameters were associated with the risk of postpartum diabetes. Out of the fetal parameters only major malformations (n=40) were predictive (OR 2 .6; CI 1.2-5.2, p=0.009). A diabetic postpartum OGTT was found in 27% of th e women who gave birth to a newborn with malformations. The fasting glucose , the AUC of the OGTT, the 50 mg diabetes screening (GCT), the history of G DM and the gestational age at diagnosis were the independent predictors in the multivariate analysis. The fasting glucose and the AUC were the best pr edictors (p=0,0001). The fasting glucose was divided into quartiles. Within the 3 rd quartile (>108 mg/dl) the OR was 3.7 (CI 1.4-11.8), and within th e 4th quartile (> 122 mg/dl) the OR was 6.8 (CI 2.1-22.2) compared to gluco se values within the lowest quartile. Diagnosis of GDM >26 weeks of gestati on (3 rd quartile) reduced the risk by half (OR 0.5, CI 0.3-0.9) compared w ith diagnosis <17 weeks. Conclusion: A postpartum OGTT should be performed in all women after pregna ncies with GDM. There is an increased risk for a persisting postpartum diab etes with prenatal fasting glucose values above 108 mg/dl, diagnosis of GDM before 26 weeks of gesta-tion, history of GDM and birth of a child with ma jor malformations.