INS and gestational diabetes: 3.2. Correlations between the Selected Clinical and Laboratory Variables as Well as PEDF Marker and CTRP3 in the Groups of: Healthy Respondents, Patients with Gestational Diabetes Mellitus (GDM), Gestational Diabetes Mellitus Treated by Means of Diet (GDM1) and by Means of Insulin Therapy (GDM2)