UCP-1 mRNA expression in VAT was significantly predicted by the patient’s age (β = -0.46, p = 0.04), gestational age (β = 0.67, p = 0.009), maternal glucose (β = 0.48, p = 0.04) and insulin level (β = -0.5, p = 0.02), together explaining 30% of its variability, whereas UCP-1 mRNA expression in placental tissue was significantly associated with the presence of GDM (β = -0.38, p = 0.04) and BMI (β = -0.48, p = 0.02), together explaining 26% of its variability. Here, UCP1 is linked to gestational diabetes.