Gestational diabetes - diagnosis, risk factors, treatment

A few words about diabetes during pregnancy

Pregnant women can suffer from two types of diabetes: pre-pregnancy diabetes and gestational diabetes. With pre-emptive diabetes we have to deal with a woman who has previously suffered from any type of diabetes (type 1 diabetes, type 2 diabetes, or less frequent types MODY and LADA). Diabetes may be uncomplicated or with complications such as: retinopathy, nephropathy, neuropathy or heart disease that are particularly dangerous to a pregnant woman. Sometimes, with a diagnosis of pre-emptive diabetes the pregnant woman only learns during the first blood test.

However, gestational diabetes (in other words: gestational diabetes mellitus, GDM, gestational diabetes mellitus) is any state of elevated blood glucose found in pregnant women who have not previously had diabetes. Gestational diabetes is currently one of the most common complications during pregnancy. Depending on the studied population, 3-10% of pregnant women are affected. Diagnosis is usually made between the 24th and the 28th week of pregnancy after the oral glucose tolerance test (OGTT).

Hormonal disorders are the main cause of gestational diabetes. In pregnancy, there is an increase in the production of a number of hormones, min. prolactin, placental lactogen, cortisol and glucagon, which are insulin antagonists. The insulin produced by the pancreas is responsible for regulating the blood sugar level. However, the above-mentioned hormones sometimes disturb the body's sensitivity to insulin and may partially block its action (causing insulin resistance to develop). This leads to an increase in the level of sugar in the blood.

Gestational diabetes, as the name suggests, disappears after childbirth. Unfortunately, it does not go unnoticed and leads to an increased risk of maternal diabetes type 2. Studies show that within 15 years of the onset of type 2 diabetes will be diagnosed in 30-45% of women who have previously been diagnosed with gestational diabetes.

Risk factors for gestational diabetes:

• body mass too high before pregnancy: overweight (BMI> 27 kg / m²) - increases the risk of gestational diabetes 2.1 times, obesity (BMI> 30 kg / m²) - 3.6-fold, and extreme obesity (BMI> 40 kg / m²) - 8.6 times,
• polycystic ovary syndrome (PCOS),
• insulin resistance,
• the age of the pregnant woman is over 35 years,
• gestational diabetes during the previous pregnancy,
• birth of a child with a body weight above 4 kg,
• a child with a defect from a previous pregnancy,
• intrauterine death in a previous pregnancy,
• a multinational (birth of at least 2 children),
• type 2 diabetes in a close family (parents, siblings
• hypertension,
• hirsutism (hypertrichosis).

When is gestational diabetes diagnosed?

We recommend testing the glucose level in a pregnant woman during the first visit to the gynecologist. If the result is normal and there are no above-mentioned factors that increase the risk of gestational diabetes, the next step is an OGTT (oral glucose tolerance test), an oral glucose load test. This test is carried out between the 24th and 28th week of pregnancy. However, in the case of women from the group of increased risk of gestational diabetes, it should be performed as soon as possible after confirmation of pregnancy.

OGTT - oral glucose tolerance test

This test consists of taking blood three times and measuring the level of glucose:

1. Fasting (or at least 8 hours from the last meal).
2. After 1 hour after drinking 75g of glucose.
3. After 2 hours after drinking 75g of glucose.

Rules for proper OGTT execution:

1. It is necessary to do the test on an empty stomach, that is, do not eat or drink, do not chew gum in the 8 hours preceding the examination.
2. In the 3 days prior to the test, the diet and amount of physical exercise should be kept the same, no major lifestyle changes should be undertaken.
3. The solution should be prepared from 75 grams of glucose (it may be tasteless, or it may have a taste e.g. lemon flavor) dissolved in 250 ml of water. Do not add a lemon to improve the taste, because it can falsify the result.
4. The solution should be drunk within 5 minutes.
5. During the test, also while waiting for subsequent blood donations, you should rest while sitting.

OGTT standards

OGTT standards in the pregnant population are updated from time to time. For example, in Poland, the standards set in 2014 are currently in force and they are as follows:

• fasting glucose level - <92 mg / dl (92 mg / dl is already an incorrect value),
• the level of glucose after 1h after drinking a 75g glucose solution - <180 mg / dl,
• the level of glucose after 2h after drinking a 75g glucose solution - <153 mg / dl.

If at least one of these values ​​is above the norm, doctors will diagnose gestational diabetes.

Treatment of gestational diabetes

The primary goal of treating gestational diabetes is to maintain a normal level of glucose in the mother's blood. Women with gestational diabetes should regularly, usually 3-4 times a day, take blood glucose measurements using a glucose meter.

Diabetes therapy usually starts with the introduction of a diabetic diet. Dietary recommendations should be adjusted individually to the patient, due to differences in body weight before pregnancy, weight gain during pregnancy, physical activity and eating habits. Dietary rules for patients with gestational diabetes are available online.

When dietary treatment proves to be insufficient, it is necessary to include insulin therapy.

The impact of gestational diabetes on a fetus

Glucose in the mother's blood passes through the placenta into the fetal bloodstream. In the case of gestational diabetes, the mother's blood glucose is too much, which can lead to hyperglycemia in the fetus as well. Uncontrolled gestational diabetes increases the risk of malformation, such as:

• fetal macrosomia (fetal weight too high in relation to fetal age),
• fetal hypotrophy (fetus too small in relation to fetal age) - more often in pre-eclampsia diabetes,
• bone defects (e.g. caudal regression syndrome),
• nervous system defects (e.g. microcephaly),
• urogenital defects (e.g. hypospadias),
• heart defects (e.g. cardiomyopathy).

and therefore gestational diabetes is a threat to both the mother's health and the development of her unborn child.

The impact of gestational diabetes in pregnant woman

Gestational diabetes significantly increases the risk of developing, the following diseases (among others) during pregnancy:

• hypertension,
• preeclampsia and eclampsia,
• urinary tract infections.