What You Need to Know about Gestational Diabetes Mellitus (GDM)

GDM is a condition where blood glucose levels rise in pregnancy

Thandi* was excited to visit her healthcare provider at 24 weeks. A scan was planned and she was looking forward to confirming her baby’s sex. What Thandi wasn’t prepared for was her doctor’s concern that sugar levels in her urine were high. She was asked to fast overnight and return for a blood test the next day. Her doctor diagnosed gestational diabetes mellitus (GDM) and Thandi was concerned about what this meant for her and her baby.

What is GDM?

GDM occurs in pregnancy when blood sugar (glucose) levels rise above what is considered normal. This is called hyperglycaemia. Although GDM does occur as a result of how your body uses insulin, it shouldn’t be confused with diabetes mellitus type 1 or 2. GDM occurs only in pregnancy. Glucose levels should return to normal after the baby’s birth. Tests will be done around six weeks after the delivery to check these. They should be repeated every two to three years. If you have had GDM, your risk for developing type 2 diabetes later in life does increase. You are also at risk for developing the condition again in a future pregnancy.

Glucose and Insulin

To understand how and why GDM occurs, we need to take a closer look at glucose and insulin. Glucose is a type of sugar found in the blood. It comes from the carbohydrate foods we eat and provides fuel for all cells our bodies. Insulin, a hormone produced by cells in the pancreas, regulates glucose levels in the blood. In pregnancy, the placenta produces hormones to help your baby grow and this increases the demand for insulin. If this additional demand cannot be properly met, or the body stops using insulin effectively, caused when pregnancy hormones block insulin from working properly (insulin resistance), glucose will stay in the bloodstream and levels will rise.

High glucose levels in the blood can lead to several health problems, and pregnancy and birth complications. Untreated, GDM can cause your baby to gain weight, leading to a baby with a high birth weight (over 4kg) and the increased likelihood of a C-section. GDM can also increase the risk for a preterm birth (before 37 weeks). GDM is a risk factor for pre-eclampsia, a serious pregnancy complication that causes high blood pressure and protein in the urine. If left untreated, GDM can result in a stillbirth or death of a baby shortly after the birth. The baby also has a higher risk for developing obesity and type 2 diabetes in later life.

At every prenatal visit, your healthcare provider will do a urine test to screen for glucose, protein or an infection in your urine. A routine glucose screening (blood test) may also be done between 24 and 28 weeks.

Some expectant moms do have an increased risk for developing GDM. These include being overweight before you conceive, moms older than 25 years, a history of diabetes in your family or if you had GDM in a previous pregnancy. If you aren’t sure if your healthcare provider is aware of your personal risk factors, let him or her know at your next appointment.

Testing and Diagnosis

GDM doesn’t usually present with symptoms and is most often picked up during routine screening.  However, if you notice that you are more thirsty than usual, need to urinate more often or you feel hungry and eat more, let your healthcare provider know, as these are symptoms of diabetes.

If your healthcare provider is concerned about your glucose levels, you may be given a glucose challenge test which can be done at any time of the day regardless of when you last ate. You will be given a sweet liquid to drink. A blood test (blood is taken from a vein in your arm) will be done an hour later. If glucose levels are high, your healthcare provider will order an oral glucose tolerance test or OGTT.

How the OGTT works:

• You will be asked to fast for eight hours prior to the test – usually overnight and you can go in for the test first thing in the morning.
• Your glucose level will be taken at the start of the test.
• You will be given 75g of glucose mixed in about 300ml of water to drink.
• Blood will be drawn at one, two and three hours and glucose levels tested.
• You cannot drink or eat anything during the test.
• Your healthcare provider will interpret the glucose levels and how your body responds to sugar and uses insulin to process it.

Staying Positive

After a diagnosis of GDM, you may feel anxious about your health and that of your baby. Learning more about the condition and what you can do to bring it under control is an essential first step.

Treatment Options

GDM must be managed or treated to prevent complications.  Some expectant moms are able to manage glucose levels through diet and exercise alone. Based on your test results, your healthcare provider may ask you to first make changes to your diet and get more exercise before you start on medication. Your levels will be monitored for a period of one to two weeks. If glucose levels do not reach an optimal range and stabilise, you will be prescribed injections or tablets to take daily.

3 Ways to Manage GDM

Check glucose levels

Glucose levels can be measured at home using a small machine called a glucometer or blood glucose meter. You will need to prick your finger using a lancet and place a drop of blood on a small strip of paper. The paper is fed into the machine and a reading is provided on the screen. Your healthcare provider will ask you to check your glucose levels as soon as you wake up in the morning and after meals – four or more times per day. You will receive a ‘target’ glucose level from your doctor and you will need to keep your levels within this range everyday. The numbers below are considered within an ideal target range, but your doctor may give you different numbers:

• Fasting: 5.3 mmol/litre
• 1 hour after a meal: 7.8 mmol/litre
• 2 hours after a meal: less than 6.7 mmol/litre

Monitor your diet

To keep glucose levels stable, eat three meals a day with healthy snacks between meals. Aim for a diet that comprise of lean proteins like chicken, eggs and fish and plenty of non-starchy vegetables like green beans, salad green, broccoli and cucumber. Carbohydrates should be included at every meal and portion sizes kept regular. Choose complex carbohydrates most often for meals, as these take longer to digest and cause blood sugar to rise more slowly. Examples are brown rice, sweet potatoes and wholewheat bread. Avoid simple carbohydrates like sugary cereals, processed snacks and sugary drinks that cause a spike in blood sugar.

Get exercise

Exercise also helps to lower blood sugar which is why it is considered an important part of a GDM management plan. Always check with your healthcare provider before you start any new exercise programme in pregnancy. Walking, prenatal yoga and swimming are good exercises to consider.

Early diagnosis of the condition and a good management strategy to control glucose levels on a daily basis, will prevent most pregnancy and labour complications caused by GDM. With a mindful approach, support and encouragement from your healthcare provider, a midwife and your support network, you can make the changes needed to stabilise glucose levels and look forward to giving birth to a healthy baby.

Contact your midwife or healthcare provider for support, advice and counselling.

* Not her real name

Resources: https://www.webmd.com/ https://www.mayoclinic.org/; https://www.lifehealthcare.co.za/; https://www.diabetessa.org.za/; https://www.tommys.org/; https://www.news24.com/; https://medlineplus.gov/; https://www.ncbi.nlm.nih.gov/; https://www.whattoexpect.com/; https://www.eatingwell.com;