Gestational Diabetes: Symptoms, Causes and Treatment

Gestational diabetes affects up to 14% of pregnant women in the world. It isn't a serious clinical entity, but it should be monitored from detection to delivery.

Written and verified by el biólogo Samuel Antonio Sánchez Amador.

Last update: 12 June, 2021

The term diabetes mellitus (DM) refers to a set of metabolic disorders, the main characteristic of which is the presence of high glucose values in the patient’s blood. Usually, we find 2 variants of this disease (type 1 and type 2), but did you know that gestational diabetes is also a medical condition?

Gestational diabetes (GDM) is the most common medical complication during pregnancy. It’s estimated that 2 to 10% of all pregnant US women will have GDM, although the global trend is currently 14% of pregnant women. Thus, it’s estimated that this clinical event characterizes about 18 million deliveries annually.

As an even more curious fact, it should be noted that women with gestational diabetes are at risk of developing diabetes mellitus 10 to 20 years after delivery, with probabilities ranging from 35-60%. If you want to know more about this pathological picture, which is as interesting as it is common, keep reading.

The basics of diabetes

As indicated by the National Library of Medicine of the United States, diabetes comprises a group of clinical conditions that are characterized by an abnormal increase in blood glucose in the patient. In type 1 diabetes, the patient doesn’t produce insulin, due to the autoimmune destruction of the cells that synthesize it, located in the pancreas.

Type 2 is the most common, accounting for 80 to 90% of total diabetes cases. While type 1 is an autoimmune disease, this variant is characterized by a lack of insulin production or its misuse. Type 2 diabetes is associated with obesity and a sedentary lifestyle and appears much more frequently in adults.

Current situation

The World Health Organization (WHO) provides us with a series of very interesting data to understand the situation of diabetes worldwide. Among them, we can highlight the following:

• The number of people with diabetes has increased dramatically. In 1980, 108 million patients were estimated to have it, and now there are 422 million.
• In 2016, diabetes killed 1.6 million people. The causes of premature death due to diabetes have increased by 5% in the last 16 years.
• Obese people have up to 6 times the risk of developing type 2 diabetes. In a world where 625 million people suffer from obesity, this factor must be taken into account.

We usually think of diabetes as a chronic but harmless condition. Nothing could be further from the truth. These diseases are a major cause of blindness, kidney, heart failure infarction, cerebrovascular accidents and many other clinical events that are life-threatening.

What is gestational diabetes (GDM)?

Gestational diabetes (GDM) is defined as any degree of diabetes that is first recognized during the patient’s pregnancy. Two variants are distinguished based on their approach. This condition can be controlled with diet (AGDM1) or, failing that, drugs may be necessary to achieve a correct glycemic index (AGDM2).

As we have said in previous lines, it is estimated that up to 14% of pregnant women in the world suffer from gestational diabetes. This translates, approximately, to 18 million cases annually. Risk factors include obesity, micronutrient deficiencies, advanced maternal age, and a family history of diabetes, among others.

In general, this condition appears in the middle of pregnancy. According to the CDC, controls for this type of diabetes are carried out during weeks 24 to 28, in order to detect metabolic irregularities in the pregnant mother. GDM can usually be controlled with lifestyle changes, but insulin treatment is sometimes necessary.

Causes of gestational diabetes

As indicated by the StatPearls medical portal, GDM is associated with two fairly clear and differentiated fronts. These are as follows:

1. The dysfunctionality of beta cells in the pancreas, responsible for producing insulin. Failing this, these cell bodies may also respond late to the patient’s glycemic indices.
2. A clear resistance to insulin due to the release of placental hormones.

During a normal pregnancy, a natural increase in maternal insulin resistance is detected over mid-gestation, and this extends into the third trimester. Several hormones secreted by the placenta (tumor necrosis factor TNF-α, human placental lactogen, placental growth hormone) are some of its causes.

This mechanism is natural at an evolutionary level. If the mother’s insulin resistance increases, there’ll more glucose to carry to the fetus to help it grow, as the maternal cells won’t use as much sugar as in a normal situation. However, this mechanism can “go over the top” and cause hyperglycemia in the mother.

Human placental lactogen (hPL) is the hormone that has been most linked to gestational diabetes. It has clear anti-insulin properties. The blood levels of hPL are directly proportional to the growth of the fetus and the placenta and peak before delivery (with figures of 5–7 milligrams/liter).

Symptoms of gestational diabetes in mothers

As indicated by the maternal nature portal What to Expect,  most mothers with GDM have no symptoms during the development of diabetes. Doctors usually request urine samples from pregnant women, and this is where an increase in circulating glucose can begin to be sensed. However, some signs such as the following are common:

• Higher-than-normal urination rates: The kidneys have to work extra hard to try to remove excess glucose from the blood, resulting in pronounced fluid excretion. For this reason, untreated diabetic patients feel the urge to urinate on a recurring basis.
• A more pronounced thirst than normal: This point is directly linked to the previous one. When the urination rate is increased, the patient is very thirsty.
• Fatigue: This symptom is difficult to differentiate from the usual gestational fatigue, so it’s never an indication of diabetes in pregnant women.

As you can see, this is a silent condition that’s always detected in routine analyses. Fortunately, with a proper diet or medication control, the symptoms do not go away and labor can continue without major complications.

Risks of GDM

However, these data do not mean that the GDM should be completely dismissed. As the Saudi Medical Journal indicates, women with gestational diabetes are at increased risk of hypertensive disorders during pregnancy. This includes gestational hypertension, pre-eclampsia, and eclampsia.

In addition to this, there is a factor that must be taken into account: diabetes that isn’t well-controlled causes an increase in sugars in the body of the fetus. This makes it look “supercharged” and, as a result, it grows more than normal. Although this sounds like a good thing, fetal overgrowth is a clear perinatal risk that can lead to a number of complications.

The first of these is a much more pronounced need for a cesarean section. The larger baby could seriously damage the mother’s birth canal at birth, so surgical removal is required. Women who go through a cesarean section take a little longer to recover, but it’s a procedure with minimal risks.

On the other hand, there are other neonatal comorbidities that, unfortunately, can’t be solved with an artificial birth canal. Children of women with untreated GDM are at risk for hyperbilirubinemia, hypocalcemia, erythema, and respiratory distress syndrome. Excess glucose isn’t good, neither for the mother nor for the baby.

Diagnosis

Diagnosing gestational diabetes is very simple. First, evidence of GDM begins to show when excessive amounts of glucose are detected in the urine in routine tests, but this sign isn’t enough on its own. As the Mayo Clinic explains, more tests are required, including the following:

• Initial glucose tolerance test: the patient should drink a glucose syrup solution. After one hour, blood sugar levels are measured, that is, the rate of glucose absorption that has taken place at the cellular level is quantified. Values of 10.6 millimoles per liter (mmol / L) indicate GMD.
• Oral tolerance study: the premise is similar to the previous one, only that the solution is even more sugary and monitoring is carried out that lasts a total of 3 hours.

Treatment of gestational diabetes

Treatment of GMD begins with non-pharmacological measures, such as dietary changes, promoting physical activity, and sustained blood glucose monitoring. It is always recommended that the patient put herself in the hands of a nutritionist, who will make a plan appropriate to the patient’s body mass index (BMI) and her needs.

If the glycemic index doesn’t improve with exercise and changes in diet, it will be necessary to resort to pharmacological treatment. This happens through the administration of insulin, in the following concentrations: in the first trimester, 0.7 units/kilogram of the patient per day are recommended, in the second 0.8, and in the third 0.9-1.

The pregnant woman must distribute these doses of insulin in 2 doses. One baseline at bedtime (half of the total) and the other half divided into 3 different intakes, one with each meal. In any case, the professional will inform each patient in each specific case regarding the framework of action.

It is recommended that women with GDM perform aerobic exercises for 30 minutes 5 days a week or, failing that, 150 minutes spread over 7 days.

An easy-to-approach pathology

Gestational diabetes is easily approached once it is detected, either with exercise and dietary changes or with pharmacological treatment, in addition to everything previously described. However, it should be noted that there are certain inherent risks (especially for the fetus) in this condition, so it shouldn’t be taken lightly.

Obesity is a clear predisposing factor when it comes to suffering from gestational diabetes and, in addition, it can bring many other complications to pregnancy. For this reason, we recommend that everyone tries to maintain an adequate body mass index (BMI), whether this is a pregnant woman or not, both for their health and that of their future offspring.