Oral Glucose Tolerance Test (OGTT) for Pregnant Women

Excess body weight (Body Mass Index > 25 kg/m²) 

Close relatives with diabetes mellitus

                                                                                                                                                                                                                    Women with a history of pregnancy complications such as preterm birth, excessive birth weight (over 4.5 kg), congenital anomalies, or stillbirths

Patients over 45 years old

Metabolic syndrome

Chronic liver diseases

Atherosclerosis, gout 

Polycystic ovary syndrome (PCOS) 

Neuropathies of unknown etiology 

Long-term use of diuretics, glucocorticoids, and synthetic estrogens

Chronic periodontitis and furunculosis

Low physical activity

History of fasting hyperglycemia or impaired glucose tolerance

Arterial hypertension of various origins and different cardiovascular diseases

Disorders of lipid metabolism: HDL < 0.9 mmol/L, triglycerides > 2.82 mmol/L

Examination time

Glucose concentration (venous plasma), mmol/l

Normal values 

Fasting: 

< 6.1 mmol/L 

2 hours after OGTT: 

< 7.8 mmol/L 

Diabetes mellitus 

Fasting:

≥ 7.0 mmol/L 

2 hours after OGTT: 

≥ 11.1 mmol/L 

Impaired glucose tolerance 

Fasting: 

< 7.0 mmol/L 

2 hours after OGTT:

≥ 7.8 and < 11.1 mmol/L 

Impaired fasting glycemia 

Fasting: 

≥ 6.1 and < 7.0 mmol/L 

2 hours after OGTT: 

< 7.8 mmol/L 

Gestational diabetes mellitus 

Fasting: 

≥ 5.1 and < 7.0 mmol/L 

2 hours after OGTT: 

≥ 8.5 and < 11.1 mmol/L 

Increased tolerance

Decreased tolerance

Reduced rate of intestinal absorption:

Increased Rate of Intestinal Glucose Absorption: 

- Hypocortisolism 

- Excess dietary glucose intake

- Hypopituitarism with secondary adrenal insufficiency 

- Hyperthyroidism 

- Intestinal diseases (steatorrhea, sprue, tuberculous enteritis, Whipple’s disease) 

- Post-gastrectomy, post-gastroenterostomy, and post-vagotomy states 

- Hypothyroidism 

- Duodenal ulcer 

Excess insulin secretion:

Increased Glycogenolysis and Gluconeogenesis:

- Insulinoma

- Hyperthyroidism

-Nesidioblastoma 

- Emotional stress or adrenal hyperfunction associated with pheochromocytoma

- Infection-related toxemia

- Pregnancy

Impaired Glycogen Formation from Absorbed Glucose:

- Liver damage

- Glycogen storage diseases (glycogenosis)

Impaired Peripheral Utilization of Glucose by Tissues:

- Pre-diabetes, diabetes mellitus, steroid-induced diabetes

- Brain trauma and intracranial processes involving damage or compression of the hypothalamic region. In such cases, glucose levels may be abnormally elevated and then gradually return toward fasting levels.