11 Sep Understanding Gestational Diabetes: Why Pregnancy Can Trigger the Condition
Dr Sam Tormey examines why many women develop diabetes for the first time during pregnancy, and looks at ways to monitor and manage the condition.
Diabetes Comes in Different Forms
Most of us know about juvenile or type 1 diabetes, and appreciate the risk of getting a far more common version of diabetes later in life – type 2 or mature-onset diabetes. But a diagnosis of diabetes is also a serious possibility during pregnancy, and a recent comprehensive overview of this less-appreciated form of the disease by the Australian Institute of Health and Welfare should prompt us to add it to our health radar.
Approximately one in 20 Australian women will develop diabetes for the first time during pregnancy. Although this is usually temporary, gestational diabetes mellitus (GDM) dramatically increases your risk of developing type 2 diabetes later in life.
Why Pregnancy Can Trigger Diabetes
It is not immediately obvious why being pregnant should trigger diabetes, but understanding more about the types of diabetes can make it less of a shock.
Glucose is our body’s primary fuel and is very tightly regulated to avoid significant fluctuations in its levels in our blood. Cells in our body cannot access the glucose they need in the bloodstream without insulin, a hormone that docks with cells and allows glucose to enter. The pancreas drip-feeds insulin into our bloodstream and adds pulses to cope with the spikes of glucose that result from meals and snacks. Adding the right amount of insulin to the glucose mix enables cells to utilise the fuel as needed, without blood glucose levels becoming too high.
Persistently high levels of glucose act as a diuretic and cause dehydration (resulting in thirst, fatigue and frequent urination in the undiagnosed diabetic). Very high or very low blood-glucose levels result in coma and death, so tight regulation at either end is essential.
The Different Types of Diabetes
In type 1, or juvenile, diabetes, there is a complete failure of the insulin-making cells of the pancreas. Giving replacement insulin by needles (or, increasingly, a continuous insulin infusion pump) is the mainstay of treatment.
The more common type of diabetes – type 2 – is quite different. Here, the problem starts with the docking receptors that allow insulin to ‘usher’ glucose into the cells. These receptors become less sensitive to insulin in some people, and a syndrome of ‘insulin resistance’ develops – the insulin and glucose are knocking on the door of the cell, but the key isn’t always turning the lock.
So the initial treatment is quite different. Weight loss and exercise can improve sensitivity to the insulin that you have, so tablets of various types can be used, and ultimately, type 2 diabetics may also need extra insulin given by needles. Although also called ‘mature-onset diabetes’, type 2 diabetes is being seen increasingly in younger adults and even in some children.
Gestational Diabetes Explained
GDM is more like type 2 diabetes. Some degree of insulin resistance is seen in a normal pregnancy, probably as a result of hormonal interference with the insulin receptor from other maternal and placental hormones.
Most women’s bodies can overcome this resistance by producing more insulin. The major physiological changes during pregnancy create stresses on various organs: the heart needs to pump more blood, the lungs need to deliver more oxygen, and glands such as the thyroid and the pancreas need to make more hormones. The pancreas is thought to produce about twice as much insulin during pregnancy as it does otherwise.
For some women, the pancreas cannot cope with these extra demands, and since there is not enough insulin to keep blood sugar levels stable, GDM may develop.
Part Two: Managing Gestational Diabetes: Diagnosis, Treatment and Long-Term Risks
Note: This article provides general health information and in no way constitutes medical advice. Ideas and information expressed may not be suitable for everyone. Readers wishing to obtain medical advice should contact their own doctor.
