INS and diabetes mellitus: 31 pregnant with GDM; mean age: 32 (SD 4) years; mean BMI: 35.2 (SD 7.9) kg/m2; exclusion criteria: type 1 or 2 diabetes mellitus, pregestational hypertension, preeclampsia during current pregnancy, preterm labor, cervical shortening, current multiple fetuses, cardiopulmonary diseases; dietary and exercise modification for diabetes suggested and insulin received, if needed