Table 2.

Potential predictors of plasma total peroxide level based on multiple linear regression with log-transformed plasma total peroxide as the outcome. To investigate the association between gender, previous pregnancy, previous GDM, GDM severity, and ON stress, a set of multiple linear regression models were built with the individual addition of dummy coded grouping variables as predictors. For the final model, only statistically significant terms were retained. Model 1: adjusted for female sex; Model 2: Model 1 + previous pregnancy; Model 3: Model 2 + previous GDM; Model 4: Model 3 + previous insulin treatment; Model 5: Model 4 with the removal of the nonsignificant GDM term. Female sex was associated with increased oxidative stress (Model 1) that was abolished by including previous pregnancy into the model (Model 2). Previous GDM did not have additional elevating effect on plasma total peroxide level upon previous healthy pregnancy (Model 3); however, previous insulin treatment itself had a positive additional impact on oxidative stress (Model 5).

Independent variable	Model 1	Model 2	Model 3	Model 4	Model 5
Female sex	0.75 ∗∗ (0.15)	0.29 (0.73)	0.29 (0.17)	0.29 (0.17)	0.29 (0.17)
Pregnancy		0.57 ∗∗∗ (0.13)	0.43 ∗∗ (0.15)	0.43 ∗∗ (0.15)	0.52 ∗∗∗ (0.13)
Previous GDM			0.207 (0.12)	0.15 (0.12)
Previous insulin treatment				0.30 (0.18)	0.36 ∗ (0.17)
R 2	0.241	0.385	0.408	0.430	0.419

Independent variable: log plasma total peroxide, n = 81, values are estimated effect sizes: B (SE), (^∗: p ≤ 0.05; ^∗∗: p ≤ 0.01; ^∗∗∗: p ≤ 0.001).