Oral glucose tolerance test in pregnancy: questions and answers

Abstract

Gestational diabetes mellitus (GDM) is one of the most common diseases during pregnancy and increases risks of shortand long-term complications to both mothers and their children. Timely treatment of GDM significantly reduces the specified risks. The development of insulin resistance in pregnancy is associated with increased secretion of maternal and fetoplacental hormones (placental lactogen, estrogens and progesterone, cortisol and prolactin) with increasing gestational age. Thus, GDM develops during pregnancy in patients with insufficient pancreatic function due to progressive hyperglycemia and insulin resistance. Oral glucose tolerance test (OGTT) is the most commonly used test in world practice to establish a diagnosis. In Russia, OGTT is carried out at a gestational age of 24–28 weeks using 75 g of glucose and assessing venous plasma glycemia values at three points: before and 30, 60, and 120 minutes after drinking the glucose solution. However, refusal of patients to complete the test is one of the problems associated with the OGTT. Nausea and vomiting are the most commonly reason for not completing the OGTT. In some cases, patients cannot complete the test due to severe tolerance to a hyperosmolar glucose solution. In such cases, a number of solutions are discussed in the literature, one of which is the possible use of glucose-based compositions comprising flavouring additives, which are allowed for use during pregnancy to improve the tolerability of the OGTT. Improving the tolerability and compliance with the procedure is one of the most important conditions for successful and timely diagnosis.