Gestational diabetes: what your blood sugar tells you during pregnancy

What is gestational diabetes?

Gestational diabetes is a form of diabetes that is diagnosed for the first time during pregnancy. Your body can no longer regulate blood sugar well enough, causing blood sugar levels to be higher than is healthy for you and your child.

It differs from "regular" type 2 diabetes in one important respect: in most women, gestational diabetes resolves on its own after delivery, because the cause is directly related to the pregnancy itself. That does not mean it is unimportant, as if left untreated it can pose risks to mother and child, and it significantly increases your risk of type 2 diabetes later in life. More on that below.

How does gestational diabetes develop?

During pregnancy, the placenta produces hormones necessary for the baby's growth. A side effect of these hormones is that they inhibit the action of insulin: insulin is the hormone that helps sugar from your blood enter the cells, where it is used as energy.

In most pregnant women, the pancreas simply produces extra insulin to compensate for this effect. In some women, this is insufficient, usually starting from the second half of the pregnancy when the placenta produces the most of these hormones. The result is blood sugar that is too high: gestational diabetes.

You have not done anything wrong here yourself. The predisposition to be unable to produce sufficient extra insulin is largely a matter of your pancreatic reserve, not of what you eat or how much you exercise during pregnancy.

Symptoms and risk factors

The tricky thing about gestational diabetes is that most women do not notice any symptoms. If there are any symptoms at all, they resemble common pregnancy complaints and are therefore easily overlooked: excessive thirst, frequent urination, and fatigue. Precisely because symptoms are so often absent, the screening test around weeks 24-28 is so important: without the test, a significant proportion of cases would go undetected. In the Netherlands you don't get automatically tested, but only if you meet the risk criteria.

Certain factors increase the risk of gestational diabetes:

• Overweight before pregnancy
• Previous gestational diabetes during a previous pregnancy
• Type 2 diabetes in the immediate family (parents, brothers or sisters)
• A previous child with a high birth weight (over 4.5 kilos)
• PCOS (polycystic ovary syndrome)
• Pregnant over the age of 35
• Ethnicity (some population groups have a higher risk)

If you have one or more of these risk factors, your midwife or gynecologist may test you earlier in the pregnancy, instead of waiting until week 24-28.

The sugar test: how does the glucose tolerance test work?

The official test is called the oral glucose tolerance test (OGTT), often colloquially referred to as the "sugar test" or "glucose load test." This is how the test works:

1. You report to the lab or hospital fasting (no food or drink, except water).

2. Blood is drawn first to determine your fasting value.

3. You drink a liquid containing 75 grams of glucose.

4. After a period of time, blood is drawn again to see how your body processes the sugar.

An abnormal fasting value or a value that is too high after drinking the glucose indicates gestational diabetes. The precise threshold values ​​differ slightly by guideline and country; Your midwife or gynecologist compares your result to the cutoff values ​​used in the Netherlands.

If there is a strong suspicion of abnormal blood sugar, for example based on previous results, a diurnal curve is sometimes used instead: measuring your blood sugar at multiple times over the course of a day to get a more complete picture of how your values ​​fluctuate throughout the day.

What does an abnormal result mean?

If you are diagnosed with gestational diabetes, this does not automatically mean that you need insulin. For most women, the first step is adjusting diet and exercise, after which blood sugar is monitored regularly. For some women, this is not sufficient, and insulin (or sometimes medication in tablet form) is needed to keep blood sugar within a healthy range.

If left untreated, persistently high blood sugar can have consequences, such as a larger-than-average baby (which can complicate delivery), an increased risk of premature birth, and a greater chance that the baby will temporarily have low blood sugar after birth. Well-treated gestational diabetes significantly reduces these risks, which is precisely why monitoring and potential treatment are so important.

Diet and lifestyle for gestational diabetes

A diet for gestational diabetes is not about minimizing carbohydrates, but about variety and choice. A few principles that are often advised:

• Distribute carbohydrates throughout the day in smaller portions, rather than large amounts at once.
• Choose whole-grain and fiber-rich products instead of products with a lot of added sugar or white flour, as these cause blood sugar to rise less rapidly.
• Combine carbohydrates with protein and fiber, for example, whole-grain bread with toppings instead of just bread.
• Stay active, if possible. Walking after a meal can help regulate blood sugar better.

A dietitian specializing in gestational diabetes can tailor this advice to your situation; This is general information, not a substitute for personal nutritional advice.

After childbirth: why monitoring does not stop

For most women, blood sugar normalizes fairly quickly after delivery because the placenta (and with it the hormones that caused insulin resistance) has disappeared. Therefore, another blood sugar test is recommended a few weeks to months after delivery to confirm that the values ​​are back to normal.

What is often overlooked: having had gestational diabetes significantly increases your risk of developing type 2 diabetes later in life, even if your blood sugar returns to normal immediately after delivery. That risk does not disappear on its own after that single check-up result; it remains elevated for life compared to women who did not have gestational diabetes.

For this reason, it makes sense to have your blood sugar checked periodically, not only immediately after delivery but also in the longer term, even if you have no symptoms at that moment. The marker Glucose (fasting) provides a snapshot of your blood sugar, while the marker HbA1c shows what your average blood sugar has been over the past two to three months, making it less sensitive to random fluctuations on the day of the test itself. Together, they provide a more complete picture than a single measurement. Conclusion Gestational diabetes develops because pregnancy hormones inhibit the action of insulin, and most women experience few symptoms themselves, which makes the screening test around weeks 24-28 so important. An abnormal result does not automatically mean that you need insulin: for many, adjusting diet and exercise is sufficient. After childbirth, the condition usually disappears, but the increased risk of type 2 diabetes later in life remains, making periodic blood sugar checks worthwhile, even long after pregnancy. In the Netherlands your blood gets tested yearly during 5 years after having gestational diabetes.

Have you had gestational diabetes and do you want to know where you stand now? A blood test provides clarity, whether that is right after delivery or years later.