Gestational diabetes screening

Gestational diabetes is a disorder of blood sugar metabolism that develops or is first detected during pregnancy. In Estonia, it is a common pregnancy complication, and early detection helps reduce risks for both the mother and the baby.
 

The aim of gestational diabetes screening is to detect a disturbance in blood sugar metabolism in time, so that dietary guidance and blood glucose monitoring can be started if needed, and fetal growth and well-being can be assessed more closely.
 

Why is gestational diabetes screening important?
 

During pregnancy, the placenta produces hormones that increase insulin resistance. In some women, the body is unable to maintain blood glucose levels within the normal range, and blood sugar values rise above normal.
 

If gestational diabetes remains undiagnosed or blood sugar levels stay high for a longer period, it may affect fetal growth, placental function, and the course of delivery. The baby may grow larger than expected, although fetal growth restriction may also occur. The risk of preeclampsia, preterm birth, induction of labor, cesarean section, and adaptation difficulties in the newborn may also increase.
 

When gestational diabetes is well monitored and controlled, pregnancy usually progresses well. It is important to diagnose the condition in time and plan appropriate follow-up.
 

Who is the screening intended for?
 

Gestational diabetes screening is recommended according to pregnancy care guidelines and the patient’s individual risk factors.
 

The risk may be higher in women who have:
 

• previous gestational diabetes;
• overweight or obesity;
• a close relative with type 2 diabetes;
• a large baby in a previous pregnancy;
• polycystic ovary syndrome;
• a previous unexplained problem related to fetal growth or the course of pregnancy;
• Suspected excessive fetal growth or increased amniotic fluid on ultrasound during pregnancy.
   

If the risk is higher, the glucose tolerance test may be performed as early as possible in pregnancy. If needed, the test is repeated at 24–28 weeks of pregnancy because gestational diabetes most often develops in the second half of pregnancy.
 

Glucose tolerance test
 

The glucose tolerance test is used to diagnose gestational diabetes.
 

The test is performed in the morning after fasting. You should not eat for at least 8 hours before the test; drinking water is allowed.
 

First, a fasting blood glucose sample is taken. You will then drink a solution containing 75 g of glucose. At Loote Ultrahelikeskus, we offer a choice of orange- or lemon-flavored drinks, served chilled.
 

Blood glucose is measured 1 hour and 2 hours after drinking the solution. The test takes about 2 hours in total.
 

Gestational diabetes is diagnosed if at least one value is above the normal range:
 

• fasting blood glucose ≥ 5.1 mmol/L
• 1-hour value ≥ 10.0 mmol/L
• 2-hour value ≥ 8.5 mmol/L
   

What happens if gestational diabetes is diagnosed?
 

Receiving the diagnosis may raise many questions. It is important to know that gestational diabetes does not automatically mean that something is wrong with the baby. In most cases, blood glucose levels can be controlled with diet, physical activity, and regular monitoring.
 

At Loote Ultrahelikeskus, we do not look only at blood sugar values. We assess the pregnancy as a whole: fetal growth, fetal body proportions, placental function, and fetal well-being.
 

If needed, additional ultrasound examinations are planned to assess:
 

• whether the fetus is growing appropriately for gestational age;
• whether there are signs of excessive fetal growth;
• whether there are signs of fetal growth restriction;
• the amount of amniotic fluid;
• placental function;
• The estimated fetal weight is relevant for delivery planning.
   

Ultrasound examinations in gestational diabetes
 

In gestational diabetes, closer assessment of fetal growth and well-being may be needed.

At 16–17 weeks of pregnancy, an early detailed fetal ultrasound may be useful in selected cases, especially if later transabdominal visibility may be limited due to maternal overweight.
 

At 20–21 weeks of pregnancy, a detailed fetal anomaly scan is performed to assess fetal anatomy and development.

In the third trimester, fetal growth assessment becomes especially important. At around 32 weeks, an ultrasound can help assess whether the fetus is growing appropriately, too quickly, or whether fetal growth restriction is suspected.
 

Towards the end of pregnancy, at around 36 weeks, ultrasound can assess the estimated fetal weight, fetal position, amniotic fluid volume, and placental function. This information can help support delivery planning if needed.
 

The role of the midwife
 

Midwife counseling plays an important role in the management of gestational diabetes.
 

Midwife Jane provides counseling on nutrition and blood glucose monitoring, performs glucose tolerance tests, and, if needed, teaches patients how to use continuous glucose monitoring. If necessary, she helps apply a Dexcom ONE+ sensor, which allows real-time, 24-hour monitoring of blood glucose levels without daily finger-prick testing.
 

Continuous glucose monitoring helps to better understand how the body responds to food, physical activity, and treatment, and may help keep blood sugar levels under more precise control.
 

If needed, we involve an endocrinologist to find the most suitable treatment plan for the patient.