Gestational Diabetes Mellitus (GDM) affects a significant number of women and it may have a big health impact on mother and fetus. It is necessary to go for a prior screening, diagnosis, and management of hyperglycemia.
Pregnancy and GDM
Pregnancy bestows a state of insulin resistance and hyper insulinemia that may predispose some women to develop diabetes in later stages of life.GDM is a condition that occurs when a woman’s pancreas fail to produce sufficient insulin to overcome high blood sugar or diabetic condition during pregnancy.
Insulin resistance during pregnancy causes due to various reasons such as modifications in growth hormone and cortisol secretion, human placental lactogen secretion (produced by the placenta and affects fatty acids and glucose metabolism thus promotes lipolysis, and decreases glucose uptake), and insulinase secretion (which is produced by the placenta and facilitates metabolism of insulin).Apart from these estrogen and progesterone also play a role in disruption of glucose insulin equilibrium. Other factors likeincreased maternal adipose deposition, decreased exercise and increased calorie intake contributes to glucose intolerance.
Universal screening approach is used for patients with norisk factors. They should undergo a 1-hour Oral glucose test at 24 to 28 weeks of gestation. Patients known possibility of glucose intolerance should be tested after conceiving. If the results are normal, then the test is repeated at the beginning of 24 weeks.
For Glucose Tolerance Test (GTT), a fasting glucose sample is collected and then the patient is given 100 g of oral glucose. Blood sample is drawn at 1 hour, 2 hours, and 3 hours.
Diagnosis of GDM is based on the presence of two or more of the following factors:
Fasting serum glucose concentration exceeding 95 mg/dL
1-hour serum glucose concentration exceeding 180 mg/dL
2-hour serum glucose concentration exceeding 155 mg/dL
3-hour serum glucose concentration exceeding 140 mg/dL
Consuming a balanced diet is essential to control GDM. Consume calories based on ideal body weight. It is recommended to consume 30 kcal/kg for women with a BMI of 22 to 25 and 24 kcal/kg for women with a BMI of 26 to 29 and 12 to 15 kcal/kg for women with a BMI above 30. Recommended overall dietary ratio is 33% to 40% of carbohydrates, 25% to 30% fat, and 30% protein.
Exercise is also important to improve glycaemic control. Exercising three or more times a week for at least 15 to 30 minutes is necessary for good GDM control.Exercising before and during pregnancy has added benefits for protection against developing GDM.
Prevalence rates of GDM are higher for African American, Hispanic, American Indian, and Asian women thanwhite women.
Risk factors includepolycystic ovarian syndrome, obesity, age older than 25 and glucosuria.
Experts recommend universal screening to diagnose GDM.
Pregnant woman with GDM who cannot controlglucose levels with diet alone may require insulin.
Pregnant woman complicated by GDM do not go beyond term.
Gilmartin A et al., Gestational Diabetes Mellitus. Reviews in Obstretics and Gynecology. 2008: V.1(3).