Researchers don't yet understand why some women get gestational diabetes and others don't. But we know that here are some risk factors that make it more likely and we have outlined these below. If you have one or more of these then you are more likely to get gestational diabetes but doctors do not yet know why. Although having a high BMI is a risk factor for gestational diabetes, slim women can also get it.
To understand what causes gestational diabetes, it can help to understand how your body uses glucose.
Your body needs some glucose in your blood to provide energy. The levels of blood glucose levels are kept at safe limits in your body, by a hormone called insulin. If your glucose level is too high, you may become unwell.
When your blood glucose level is high (such as after a meal), insulin allows the extra glucose to be stored in your cells for later use. Then, when your blood glucose levels fall, another hormone (glucagon) releases some of that stored glucose to keep enough energy available to your body.
When you are pregnant, your body produces high levels of hormones. Some of these hormones stop insulin working as well as it normally does. Usually, the body responds by increasing the amount of insulin it produces. However, some women do not produce enough of this extra insulin, resulting in gestational diabetes.
"My health was fine until about 26 weeks into my pregnancy. Then at a routine appointment they noticed glucose in my urine, so they said they needed to do a test to rule out gestational diabetes. They told me I had it and asked me to attend the diabetic clinic the following day." Gemma, mum of one
Risk factors for gestational diabetes
- you had a body mass index (BMI) of more than 30 before you became pregnant
- you have previously given birth to a baby weighing 4.5kg (around 10lb) or more (macrosomia)
- you had gestational diabetes in a previous pregnancy
- you have a parent, brother, sister or child with diabetes
- your family are of black Caribbean, black African, South Asian or Middle Eastern origin.
Some women who develop gestational diabetes do not fall into any of these categories. They may have been tested for other reasons, such as glucose in the urine or if their baby seems large. As we find out more about gestational diabetes, more women from different risk categories are being tested. Being tested does not mean that you have it – just that you may be at higher risk.
Most women are daunted initially by the unfamiliar territory they find themselves in with gestational diabetes. Find some tips here on how to cope mentally.
Today, for women with gestational diabetes, the emphasis is on trying to keep the birth as normal as possible unless there is a particular reason to do things differently.
Women who are overweight are at higher risk of developing gestational diabetes, although many women who develop it are not overweight at all.
Exercise during pregnancy has a wide range of benefits for you and your baby. If you have gestational diabetes, you have even more reason to exercise: it can help reduce your blood glucose.
If you have gestational diabetes, your diet will become an important part of managing your condition and keeping your pregnancy safe.
Gestational diabetes is treated by making changes to diet and exercise to manage blood sugar levels, and using medication if necessary.
If you have gestational diabetes, measuring your own blood glucose levels will become something you do regularly. It’s very important - it helps to guide your treatment and lifestyle, to reduce the risks for you and your baby.
Some women can control their glucose levels through diet and exercise alone but the majority will need to take tablets or injections to help control it.
ℹLast reviewed on June 16th, 2015. Next review date June 16th, 2018.