Fig. 2

The relationships between early pregnant serum uric acid levels and outcomes of gestational diabetes mellitus (A), preterm birth (B), low birth weight (C), macrosomia (D), small for gestational age (E), and large for gestational age (F) based on the generalised additive regression models (n = 18,250). The covariates were maternal age, BMI, parity, and gestational weeks of uric acid measurement. Dotted lines represented the 95% confidence intervals. When the equivalent degrees of freedom (edf) value was close to 1.0, the relationship between uric acid and outcome tended to be linear. When the edf value was further from 1.0, the relationship between uric acid and outcome tended to be non-linear. A-p value of less than 0.05 indicates a statistical association between uric acid and outcome in the GAMs model