Longitudinal changes in glucose metabolism in women with gestational diabetes, from late pregnancy to the postpartum period

AIMS/HYPOTHESIS

This study aimed to determine, in women with gestational diabetes (GDM), the changes in insulin sensitivity (Matsuda Insulin Sensitivity Index; IS_OGTT), insulin response and disposition index (DI) from late pregnancy (34-37 weeks gestation, T1), to early postpartum (1-5 days, T2) and late postpartum (6-12 weeks, T3). A secondary aim was to correlate the longitudinal changes in maternal lipids, adipokines, cytokines and weight in relation to the changes in IS_OGTT, insulin response and DI.

METHODS

IS_OGTT, insulin response and DI were calculated at the three time points (T1, T2 and T3) using the results of a 75 g OGTT. Adipokines, cytokines and lipids were measured prior to each OGTT. Linear mixed-effects models were used to compare changes across each time point. Changes in IS_OGTT, insulin response and DI were correlated with changes in maternal adipokines, cytokines and lipids at each time point.

RESULTS

A total of 27 women completed all assessments. Compared with T1, IS_OGTT was 11.20 (95% CI 8.09, 14.31) units higher at 1-5 days postpartum (p < 0.001) and was 5.49 (95% CI 2.38, 8.60) units higher at 6-12 weeks postpartum (p < 0.001). Compared with T1, insulin response values were 699.6 (95% CI 957.5, 441.6) units lower at T2 (p < 0.001) and were 356.3 (95% CI 614.3, 98.3) units lower at T3 (p = 0.004). Compared with T1, the DI was 6434.1 (95% CI 2486.2, 10,381.0) units higher at T2 (p = 0.001) and was 4262.0 (95% CI 314.6, 8209.3) units higher at T3 (p = 0.03). There was a decrease in mean cholesterol, triacylglycerol, LDL-cholesterol and VLDL-cholesterol from T1 to T2 (all p < 0.001), and an increase in mean C-reactive protein, IL-6 and IL-8 from T1 to T2 (all p < 0.001). Mean leptin decreased from T1 to T2 (p = 0.001). There was no significant change in mean adiponectin (p = 0.99) or TNF-α (p = 0.81) from T1 to T2. The mean maternal BMI decreased from T1 to T2 (p = 0.001) and T3 (p < 0.001). There were no significant correlations between any measure of change in IS_OGTT, insulin response and DI and change in maternal cytokines, adipokines, lipids or weight from T1 to T2.

CONCLUSIONS/INTERPRETATION

In women with GDM, delivery was associated with improvement in both insulin sensitivity and insulin production within the first few days. Improvement in insulin production persisted for 6-12 weeks, but insulin sensitivity deteriorated slightly. These changes in glucose metabolism were not associated to changes in lipids, leptin, inflammation markers or body weight.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02082301.