Characteristics of pregnancy with gestational diabetes mellitus and the consecutive pregnancy as predictors for future diabetes mellitus type 2

Aim: To explore possible obstetrical history-related, modifiable risk factors of future type 2 diabetes mellitus (T2DM), with focus on characteristics of the index gestational diabetes mellitus (GDM) pregnancy and the consecutive pregnancy. Methods: This retrospective, population-based, cohort study included 788 women with GDM, who had consecutive deliveries at Emek Medical Center during 1991-2012. Women with pre-existing diabetes were excluded. Factors associated with T2DM development were examined using stepwise multiple Cox regression model. Results: Overall 178 women developed T2DM (23%). Multivariable analysis demonstrated that the most significant independent risk factors for T2DM development were birth weight >= 4000 g (HR(adj)1.7 95% CI [1.001-2.8]), fasting oral glucose tolerance test value (OGTT, HR(adj)1.03 95% CI [1.01-1.04], 1-hour post-OGTT glucose value (HR(adj)1.01 95% CI [1.006-1.02]), earlier gestational week in which GDM was diagnosed (HRadj 0.96 95% CI [0.93-0.99]), higher parity (HRadj 1.15 95% CI [1.06-1.25] and GDM recurrence in the consecutive delivery (HR(adj)2.4 95% CI [1.6-3.7]). Kaplan Meier survival curve of the time from the consecutive pregnancy until T2DM development showed a statistically significant effect of GDM recurrence and the risk for T2DM. Body mass index (BMI) gain between pregnancies and inter-pregnancy interval were not independent risk factors for T2DM. Conclusions: Obstetric characteristics of women with GDM and particularly GDM recurrence are associated with increased risk for T2DM. Strategies to prevent those factors and especially GDM recurrence might reduce the risk of future T2DM.