Understanding the Glucose Challenge Test: A Key Diagnostic Tool for Gestational Diabetes
The glucose challenge test (GCT) determines how the body reacts to sugar (glucose). Gestational diabetes is a disorder that causes elevated blood sugar levels during pregnancy and can affect your gravidity and your baby’s health. Expectant mothers can control gestational diabetes by consuming wholesome foods, exercising, and taking medication.
In women with gestational diabetes, blood sugar returns to normal soon after delivery. However, if you have had gestational diabetes, you are more likely to develop type 2 diabetes.
If your blood sugar levels fluctuate often, your doctor will recommend a screening test. There are two stages to GCT. You start by drinking a sugary solution. Later, your doctor will draw a blood sample to determine blood sugar levels. Fortunately, most women with gestational diabetes have healthy infants.
What is a glucose challenge test?
GCT tests blood glucose levels one hour after consuming 50 gm of glucose dissolved in approximately 300 ml water. As we all know, glucose is a simple type of sugar that serves as the energy source for all of the body’s cells and is the sole energy source for the nervous system. It breaks down carbohydrates in the body to their simplest form, glucose absorbed by the intestines and transferred to different organs by the blood. Cells in these organs then use glucose to produce energy, with excess stored as glycogen in the liver for short-term storage or triglycerides in fat tissues for long-term storage.
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Insulin is a hormone produced by the pancreas that aids in the uptake, utilization, and extra storage of glucose after absorption in the intestines. Insulin regulates the reuptake of glucose in organs that need it, such as the heart, brain, and functioning muscles. It also controls the storage of extra glucose and blood sugar levels. We know with meals, the blood sugar level increases and insulin secretion brings it down to normal. When the blood glucose level falls, it releases the pancreatic hormone glucagon. Glucagon instructs the liver to turn processed glycogen into glucose and release it into the blood. Insulin and glucagon work together to generate a feedback loop that keeps blood glucose levels within normal limits. An imbalance in their activity may cause an excess or deficiency of blood sugar.
An hour after administering a sugar solution, the GCT examines glucose in pregnant women’s blood. Extra sugar in the blood means it is not being used or processed. Your doctor usually conducts it as part of a panel of tests during pregnancy, although they may recommend it at any time. You will need to retake the examination at 24 to 28 weeks of pregnancy to diagnose gestational diabetes.
What are the risks associated with the glucose challenge test?
The GCT test is risk-free. However, since this test requires a needle prick to obtain a blood sample, a patient can experience increased bleeding, hematoma formation (blood accumulation under the skin), swelling, or infection at the site of a needle prick in rare cases.
How can you prepare for the glucose challenge test?
You do not need to prepare specifically for the glucose challenge test. You can eat and drink as per usual.
What can you expect from the glucose challenge test?
Doctors carry out the glucose challenge test in two steps.
- You begin by drinking 50 grams of sugar or glucose solution.
- Your doctor checks your sugar levels after an hour.
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You may be required to wait in your doctor’s clinic or laboratory until your blood sugar level reports arrive. In the following hour, the doctor will take another blood sample from a vein in your arm. They will quantify your blood sugar level utilizing this sample of blood. You can resume your normal activities following the GCT.
What are the possible results of the glucose challenge test?
Blood sugar levels less than 130 to 140 mg/dL (7.2 to 7.8 mmol/L) are routine. A cut-off value of 140 mg/dL (7.8 mmol/L) detects gestational diabetes in 80% of women. Furthermore, a cut-off value of 130 mg/dl (7.2 mmol/L) detects gestational diabetes in 90% of women.
Blood sugar levels higher than the range shown increased blood sugar because of the inability of the body to process it. Raised blood sugar levels in subsequent tests showed a strong possibility of gestational diabetes.
When should you consult a doctor?
If your blood sugar levels are higher than the normal range for women during pregnancy, please consult a doctor for a plan to get a diagnosis of gestational diabetes and develop a plan to manage it.
Conclusion:
GCT is for screening for high blood sugar with risk factors for diabetes in pregnancy and detecting gestational diabetes.
FAQs about the glucose challenge test
What additional tests will your doctor order if your GCT results are abnormal?
In the event of an irregular GCT outcome, your doctor recommends the following tests
- HbA1c test
- Two-hour and three-hour glucose tolerance tests
- Postprandial glucose test
- Urine glucose test
- Lipid profile test
What is the impact of gestational diabetes on the baby?
Gestational diabetes may have a significant effect on the newborn’s health. It may also cause increased birth weight, jaundice, polycythemia (high red blood cell mass), and incomplete respiratory system growth.