Sugar curve – what the test is about and how to interpret the results

Gestational diabetes affects between 3 and 5% of all pregnant women. In order to inhibit its development or equalize blood glucose levels, a mandatory screening test known as a sugar curve in pregnancy must first be performed. Pregnant women should not delay this test, as gestational diabetes carries great risks for both mother and child. It is recommended that the glucose load test be performed in the second trimester between 24 and 28 weeks of pregnancy. 

Sugar curve in pregnancy – when to perform the test?

In Poland, the sugar curve is one of the screening tests. It is important for every mom-to-be to be aware of when the sugar curve in pregnancy should be performed. If a woman did not have diabetes before pregnancy, it is recommended to perform this test between 24 and 28 weeks of pregnancy. However, women at increased risk of gestational diabetes perform the glucose load test earlier, and the date of the test is set by the attending physician.

Predisposing factors for diabetes in pregnancy include:

• Age over 35,
• obesity,
• hypertension,
• The occurrence of gestational diabetes in previous pregnancies, 
• PCOS, or polycystic ovary syndrome,
• positive family history,
• The occurrence of macrosomia, i.e., too much weight of the baby in relation to the gestational age.

What is the sugar curve?

In order for the results of the sugar curve in pregnancy to be reliable, one should not prepare specially. There should be no change in diet or increase in physical activity. It is necessary for a pregnant woman to be healthy, as even a slight cold can affect test results. Tell your doctor if you are taking any medications, mainly betablockers or psychotropic drugs. You should come to the test on an empty stomach, meaning you should not eat or drink anything for at least 8-10 hours before the test. 

The sugar curve in pregnancy is a multi-step test. First, fasting blood sugar levels will be tested. A glucose solution is then prepared, which the pregnant woman drinks. Glucose is measured one hour and two hours after drinking a 75 g glucose solution. 

Interpretation of sugar curve results 

Sugar curve in pregnancy norms:

1. fasting test – less than 92 mg/dl

The result 92-125 mg/l indicates gestational diabetes.

2. glycemic testing after one hour: less than 180 mg/dl. 

3. test after two hours – normal glycemia is glucose level below 153 mg/dl

If fasting glucose levels are found above 126  mg/dl in an OGTT, or after 2 hours: above 200 mg/dl, we are dealing with diabetes insipidus in pregnancy (DIP).

Treatment of gestational diabetes

Once the diagnosis is made, the woman must immediately go for a consultation with a diabetologist. It is then necessary to change existing habits. The daily caloric intake for a pregnant woman depends on  her pre-pregnancy BMI, but should usually be between 1800 and 2500 kcal. The diet should be well balanced and consist of 3 main meals and 3 snacks (including one before bed). A diabetic diet should contain about 40-45% carbohydrates, 30% protein and 20-30% fats. 

It is also recommended to introduce moderate physical activity adapted to pregnancy.

Pregnant women with gestational diabetes must take blood glucose measurements every day on an empty stomach and one hour after each meal. If changing the diet and introducing optimal physical activity do not help, insulin injections will be necessary. Pregnant women give themselves injections at home. 

Complications of gestational diabetes

Complications can be divided into two groups: maternal and fetal. 

Maternal complications:

• urinary tract infection,
• The transformation of gestational diabetes into type two diabetes after delivery, 
• polypores,
• Gestosis, or pregnancy poisoning,
• pyelonephritis, 
• swelling.

Fetal complications:

• congenital defects,
• cardiovascular defects, 
• Macrosomia, which is an excessively rapid increase in the baby’s weight relative to gestational age,
• defects in the nervous system,
• mental retardation,
• gastrointestinal defects,
• limb deformities.

If macrosomia develops, natural delivery is not possible, it is necessary to complete the pregnancy by cesarean section, which is scheduled for approximately 37 weeks of pregnancy. This is related to the accelerated development of the baby in the womb, caused by excess blood sugar. A newborn baby immediately after birth is at risk of what is known as a “newborn”. Underdiabetes, or hypoglycemia, which in extreme cases can cause hypoglycemic coma. In the child’s later development, macrosomia can cause: metabolic disorders, overweight and obesity, impaired glucose tolerance, hypertension and insulin resistance.