What is Gestational Diabetes (Pregnancy Diabetes)?
Gestational diabetes mellitus (GDM) refers to any type of blood sugar intolerance that begins or is first discovered during pregnancy. We can split GDM into two types, A1GDM and A2GDM. A1GDM, also known as diet-controlled gestational diabetes, is managed without medication and responsive to dietary changes. A2GDM, meanwhile, requires medication to properly control blood sugar levels.
In the past, screening for gestational diabetes involved looking at a patient’s history, previous pregnancy outcomes, and the family’s history of type 2 diabetes. However, this method was not ideal as it failed to identify about half of the pregnant women with GDM. A significant study in 1973 proposed using a 50 g, 1-hour oral glucose tolerance test as a better way to screen for gestational diabetes. This method has proven very effective and is now used by roughly 95% of obstetricians in the US to screen for GDM during pregnancy. In 2014, the U.S preventive service task force recommended screening all pregnant women for GDM at 24 weeks of pregnancy.
What Causes Gestational Diabetes (Pregnancy Diabetes)?
Gestational diabetes, a form of diabetes that appears during pregnancy, seems to be caused by two main issues: 1) a problem with the pancreas’s beta cells that produce insulin, or a slow response of these cells to sugar levels, and 2) a significant increase in insulin resistance due to the release of hormones from the placenta.
The primary hormone responsible for this increase in insulin resistance is the human placental lactogen. However, other hormones like growth hormone, prolactin, corticotropin-releasing hormone, and progesterone also play a part in causing insulin resistance and high sugar levels during pregnancy.
Several risk factors can increase the chance of developing gestational diabetes. These include:
- Being overweight (having a body mass index over 25)
- Lack of physical activity
- Having a close family member with diabetes
- A history of gestational diabetes or a previous baby born large
- Other health issues such as high blood pressure
- Low levels of ‘good’ cholesterol (HDL)
- High levels of triglycerides (a type of fat in the blood) over 250
- Polycystic ovarian syndrome, a condition affecting women’s hormones
- A measure of blood sugar control (Hemoglobin A1C) over 5.7
- An abnormal result on an oral glucose tolerance test, a test of the body’s ability to handle sugar
- Signs of insulin resistance such as a skin condition called acanthosis nigricans
- A history of heart diseases
Risk Factors and Frequency for Gestational Diabetes (Pregnancy Diabetes)
Gestational diabetes, a condition that impacts between 2 to 10% of pregnancies in the United States. Women who have had gestational diabetes are 35 to 60% more likely to develop diabetes mellitus, a long-term health condition, within 10 to 20 years after their pregnancy.
Signs and Symptoms of Gestational Diabetes (Pregnancy Diabetes)
Gestational Diabetes Mellitus, or GDM, is a condition that affects some women during pregnancy. In order to assess the risk or presence of GDM, doctors consider several factors. This includes a woman’s history of births and whether there is a family history of type 2 diabetes. Symptoms of the condition can vary greatly, it may cause an unusually high weight gain, obesity, or an increased body mass index during pregnancy. If a woman shows these signs, doctors will typically test her for gestational diabetes when she is 24 to 28 weeks pregnant. It’s important to take into account that the pregnancy’s outcome can be influenced by the stage at which GDM starts.
Testing for Gestational Diabetes (Pregnancy Diabetes)
It’s recommended to test for gestational diabetes between 24 to 28 weeks of pregnancy using a 50-g, 1-hour oral glucose challenge test. If the results are higher than usual (at or above 130 mg/dL or 140 mg/dL), a follow-up test, which involves a 100-g, 3-hour oral glucose tolerance test, is required. Specific abnormal results during each hour of the test can help confirm a diagnosis of gestational diabetes.
The American Diabetes Association (ADA) suggests early screening for possible diabetes in pregnant women who are overweight, inactive, or have diabetes in the family. Other risk factors include belonging to a high-risk ethnicity, previously having a big baby (weighing 4000 grams or more), a history of gestational diabetes or hypertension, abnormal levels of HDL or triglycerides, polycystic ovarian syndrome, or other conditions linked to insulin resistance.
While browsing, it’s important to remember that A1C levels, which measure your average blood sugar levels over the past 3 months, can be used. However, an A1C test may not be as reliable as an oral glucose tolerance test.
The ACOG suggests keeping blood glucose levels below 95 mg/dL when fasting, under 130-140 mg/dL one hour after meals and below 120 mg/dL two hours after meals during pregnancy.
After giving birth, it is recommended to keep an eye on glucose levels from 24 to 72 hours. After the placenta is delivered, insulin resistance usually decreases, which can help lower any treatment needed for high blood sugar. The aim of the treatment will be to maintain a balanced blood glucose level. Additionally, it would help to get a 75g oral glucose tolerance test between 4 to 12 weeks after delivery to rule out the development of type 2 diabetes.
Treatment Options for Gestational Diabetes (Pregnancy Diabetes)
Managing gestational diabetes, which is diabetes that develops during pregnancy, typically starts with lifestyle changes such as a healthy diet, regular exercise, and monitoring blood sugar levels. The American Diabetes Association (ADA) suggests that a dietitian can offer advice on a personalized eating plan, based on a person’s body mass index (BMI). If a dietitian is not available, a physician can provide guidance on topics like calorie intake, meal distribution, and carbohydrate consumption.
When it comes to exercise, the recommendation for pregnant women with gestational diabetes is to engage in moderate-intensity aerobic exercise for 30 minutes, at least five days a week. This sums up to a minimum of 150 minutes of exercise per week.
However, if blood sugar levels remain high despite these lifestyle adjustments, medication may be needed. The ADA’s first choice of treatment in such cases is insulin, which has long been the standard treatment when diet and exercise are not enough to manage gestational diabetes. Insulin may be used when fasting blood sugar levels are 95 mg/dL or higher, 1-hour glucose levels are 140 mg/dL or more, or 2-hour glucose levels are above 120 mg/dL.
Some oral medications, such as metformin and glyburide, are also being used more frequently, even though they lack FDA approval specifically for gestational diabetes. Glyburide is usually started at a low dose of 2.5 mg, up to a maximum dose of 20 mg. Similarly, metformin therapy should start with a smaller dose of 500 mg per day, with a maximum daily dose of 2500 mg.
The amount (dose) of insulin required for each patient can be calculated using their body weight. For instance, basal (long-acting) insulin dose is 0.2 units per kilogram of body weight per day. If blood sugar levels rise after a meal, “quick-acting” insulin can be taken before meals, beginning with 2 to 4 units. The total daily dose of insulin varies with each trimester: 0.7 units/kg/day in the first trimester, 0.8 units/kg/day in the second, and 0.9 to 1 units/kg/day in the last trimester.
This total daily dose is divided into two parts: half is given as a long-lasting insulin at bedtime, and the rest is divided into three parts, taken before each meal as a quick-acting insulin.
Certain types of insulin, like lispro and aspart, are approved for use during pregnancy. Short-acting insulin is generally associated with a lower risk of low blood sugar episodes. Long-acting insulin, like detemir, is also approved for use during pregnancy and is less likely to cause overnight low blood sugar episodes.
What else can Gestational Diabetes (Pregnancy Diabetes) be?
Unfortunately, many women aren’t screened for diabetes before becoming pregnant. This can make it difficult for doctors to tell the difference between diabetes that was already present before pregnancy and gestational diabetes, a type of diabetes that develops during pregnancy.
What to expect with Gestational Diabetes (Pregnancy Diabetes)
The guideline suggests that a 75g oral glucose tolerance test is given at 4 to 12 weeks after childbirth. This test is important to check for the possible emergence of type 2 diabetes, impaired fasting glucose or disturbed glucose tolerance test.
The American Diabetes Association (ADA) and the American College of Obstetricians and Gynecologists (ACOG) advise that women who had gestational diabetes mellitus (GDM) and normal post-delivery screening results should redo the test every 1 to 3 years.
Possible Complications When Diagnosed with Gestational Diabetes (Pregnancy Diabetes)
Gestational diabetes, a condition that can develop during pregnancy, can lead to several complications for both the mother and the baby. These complications are quite varied and can impact the well-being of both parties involved.
The complications that may affect the baby include:
- Macrosomia, which is when the baby is significantly larger than average
- Neonatal hypoglycemia, or low blood sugar in the newborn
- Polycythemia, a high level of red blood cells
- Shoulder dystocia, a birth injury that happens when baby’s shoulders get stuck
- Hyperbilirubinemia, a condition that causes yellowing of the baby’s skin and eyes
- Neonatal Respiratory Distress Syndrome, a breathing disorder
- An increase in perinatal mortality, or a higher risk of death around the time of birth
- Hypocalcemia, or low calcium in the blood.
For the mother, complications may include:
- Hypertension, or high blood pressure
- Preeclampsia, a pregnancy complication characterized by high blood pressure and signs of damage to another organ system
- A higher risk of developing diabetes mellitus, a long-term condition where the body can’t control the amount of sugar in the blood
- An increased chance of having a cesarean delivery, or C-section.
Preventing Gestational Diabetes (Pregnancy Diabetes)
Teaching patients is crucial. By learning about the right dietary changes, physical activity, and lifestyle adjustments, patients with gestational diabetes can significantly improve their health outcomes.