What is gestational diabetes?
Gestational diabetes (often referred to as GDM) is a common endocrine condition diagnosed in pregnancy. Pregnancy causes a number of hormones to be released that can make the body resistant to insulin, an important hormone that lowers blood sugar levels. When there is not enough insulin released from the pancreas in response to the body’s insulin resistance, gestational diabetes can develop. If gestational diabetes is undiagnosed or untreated, it can lead to the baby growing big, which can cause complications for the mother, baby or delivery.
Why does gestational diabetes occur?
The risk factors for gestational diabetes include
- Ethnicity, including African, Asian, Aboriginal, Torres Strait Islander, Pacific Islander, Maori or Middle Eastern backgrounds
- Maternal age, > 40 years
- Polycystic ovary syndrome
- Previous history of GDM
- History of macrosomia or still birth
- Family history of first degree relatives with GDM or T2D
- Pre-pregnancy BMI >30kg/m2
- Use of corticosteroids and antipsychotics in pregnancy
When is gestational diabetes diagnosed?
Gestational diabetes is most commonly diagnosed between 24-28 weeks of pregnancy. Sometimes, your doctor may talk to you about diagnosing gestational diabetes earlier in pregnancy.
How is gestational diabetes occur?
Most women will be advised to have a 75g oral glucose tolerance test done in pregnancy. You are asked to fast from 10pm the night before the test and then arrive for the test at a pathology centre before eating breakfast. A blood test is taken to measure blood sugar and then you are asked to drink a sugary beverage and have your blood sugar level tested at 1 and 2 hours after the drink. It is normal to feel a little nauseous after the test. You will be informed about the results of the test by your doctor or midwife. If the results are above the recommended levels, you have GDM.
How is gestational diabetes treated?
Gestational diabetes is always managed by lifestyle modification which includes dietary adjustments and regular exercise. Your doctor will individualise the treatment plan that best suits you. You will be asked to monitor blood sugar levels. Typically, we ask you to check your blood sugar levels when you wake up, and 1 or 2 hours after your meals. In almost half of all pregnancies with GDM, medications are needed to manage gestational diabetes, such as metformin or insulin. If medications are required in your pregnancy, your doctor will discuss the options and assist you with understanding the medication that is right for you.
Is there any long-term implications of gestational diabetes?
It is really important that women who have had gestational diabetes ensure that the diabetes has “gone away” by having another 75g oral glucose tolerance test 6-12 weeks after the baby is born. Because women who have had GDM are at higher risk of developing type 2 diabetes later in life, you should discuss with your doctor about having regular testing for diabetes at least each 2 years.
Can I prevent gestational diabetes?
Many of the risk factors for gestational diabetes cannot be changed by you (e.g., family history, age, ethnicity). However, it is advisable to maintain a healthy diet and exercise regularly before and during pregnancy. You can speak to your doctor about ways to improve the pregnancy outcomes for you and your baby.