Why Is a Glucose Challenge Test Performed in Pregnancy?

What Is the Glucose Challenge Test in Pregnancy?

Patients who have not had diabetes before and who develop a disorder of sugar metabolism for the first time during pregnancy are defined as having gestational diabetes, or pregnancy diabetes as it is commonly known.

For this purpose, the "50 g Glucose Screening Test" is performed between weeks 24 and 28 of pregnancy. For this test, at any time of day, regardless of whether she is fasting or has eaten, the expectant mother is given water containing 50 g of glucose to drink, and 1 hour later her blood sugar (venous plasma glucose level) is measured.

A 100 g OGTT (oral glucose tolerance test) is performed on pregnant women whose blood sugar is found to be 140 mg/dL or higher. The test must be repeated with 100 g of glucose over three hours. After the 3-hour challenge, whether the expectant mother has gestational diabetes is determined definitively.

After the glucose challenge test, the expectant mother should not engage in excessive physical activity and should not eat anything during this period. These are important for the glucose challenge test to give an accurate result.

What Are the Risks of Gestational Diabetes for the Expectant Mother and the Baby?

Diabetes that exists before pregnancy or develops during pregnancy creates certain risks for the expectant mother and the baby. The more regular the blood sugar levels of pregnant women with diabetes are kept during this period, the more the risks caused by diabetes are reduced.

The risks of diabetes that develops during pregnancy are lower than those of diabetes that existed before pregnancy. However, it must be identified with a glucose challenge test in pregnant women and treated. Otherwise, problems such as preeclampsia, high blood pressure, premature birth and miscarriage are more common in expectant mothers than in pregnant women without diabetes.

Babies of women who had diabetes before pregnancy may have some anomalies. However, diabetes that starts in pregnancy does not cause such a problem. In both types of diabetes, though, the baby may be born overweight, that is, macrosomic baby development may occur. In this case, because the expectant mother will give birth by cesarean section, some related risks may be experienced.

When blood sugar levels are brought under control during pregnancy in expectant mothers, the risks that may arise will decrease proportionally. For this reason, monitoring HbA1C and glucose levels in expectant mothers is extremely important.

What Are the Risks to the Baby When the Expectant Mother Has Diabetes?

1. Respiratory distress may occur in the baby after birth because the lungs are not sufficiently developed.
2. The baby being large,
3. The baby being smaller than it should be,
4. Risks of hypoglycemia (low blood sugar) after birth, hypocalcemia, polycythemia and hyperbilirubinemia (jaundice),
5. Development of heart disease at an advanced stage,
6. Kidney anomalies,
7. Anomalies of the brain and central nervous system,
8. Ear anomalies,
9. Anomalies of the digestive system,
10. In pregnant women with gestational diabetes that is undiagnosed and not monitored, the likelihood of problems in their babies is 2 times higher than in normal pregnancies.

How Is Gestational Diabetes Treated?

If gestational diabetes is present, expectant mothers are not given oral anti-diabetic medications as ordinary diabetic patients are. Instead, treatment methods such as diet, exercise and insulin administration are preferred.

The expectant mother's nutrition is arranged with a diet program suited to her pregnancy, prepared jointly by the doctor and the dietitian. This meal plan does not include chocolate, ice cream, syrup-based desserts or foods made with white flour.

During this diet, the expectant mother doing the exercises recommended by the doctor is also effective in regulating blood sugar levels. These exercises should be chosen from sports such as walking and swimming. In expectant mothers for whom these measures are not beneficial, diabetes is brought under control by giving insulin.

Pregnant women diagnosed with gestational diabetes have a 75 g OGTT performed 6 weeks after birth to investigate their glucose metabolism.