Monday 24 June 2019

Gestational diabetes: the facts

With gestational diabetes affecting 5 to 10pc of the pregnant population, many pregnant women will have questions or concerns about it. We talked to Prof Fionnuala McAuliffe from the Institute of Obstetricians and Gynaecologists about its causes and its treatment.

The term gestational diabetes can strike fear into any pregnant woman, but the condition is very manageable, and with proper treatment should disappear after pregnancy.

There are two kinds of diabetes: the kind that affects the general population (type one and two), and gestational diabetes, which can affect some women during pregnancy.

Type one and type two diabetes affect women before pregnancy, with half to 1pc of the pregnant population suffering from the condition. Once diagnosed with this type of diabetes, you will have it for life. In the majority of cases, women will know they have type one or type two diabetes before becoming pregnant.

Consultant obstetrician and gynaecologist Prof Fionnuala McAuliffe says it is important that people with diabetes seek advice from their doctors before conceiving.

Affecting 5 to 10pc of the pregnant population, gestational diabetes differs because, for the most part, it tends to be temporary, coming on during pregnancy and disappearing after it.

The reason some women get gestational diabetes is because the placenta produces a hormone that interferes with glucose metabolism. As the placenta gets bigger, it prevents the breakdown of the glucose, so those women who develop gestational diabetes tend to get it during the second half of pregnancy.

Diabetes can affect the development of the foetus. It can lead to excess growth of the baby, which can increase risks during labour and delivery. Larger babies often require Caesarean deliveries. In some cases, the woman’s high insulin levels can pass to the baby, so when they are born their blood sugar levels can drop.

Certain women are particularly at risk of developing gestational diabetes. They include: those who are overweight or obese, and have a body mass index of over 30; women over the age of 40; women from certain ethnic groups, including those from India, the Philippines and China; those who have previously given birth to a large baby; and those who have a first-degree relative (brother, sister or parent) with type two diabetes.

For the most part, the hospital will identify women who are at risk of developing gestational diabetes and carry out a glucose tolerance test, says McAuliffe. This usually takes place between 26 and 28 weeks of pregnancy, and involves fasting, drinking a glucose solution, and having blood samples tested, she says.

“Sometimes women don’t fall into the at-risk category, and in these circumstances, we usually catch that they have it through seeing extra glucose in the urine, if she looks like she’s carrying large for her dates, or if there is extra water around the baby,” says McAuliffe.

The good news is that treatment of gestational diabetes is quite easy, and for the majority of women it can be done without any drugs. The main aim of treatment is to control blood sugar levels, which most often is done through regular testing, a healthy diet and exercise.

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“Once diagnosed you will receive lifestyle advice, which is based around having a low-sugar diet. This is not a weight-reducing diet but involves exchanging high-sugar foods for low-sugar foods,” says McAuliffe.

She suggests avoiding fizzy drinks, cakes, biscuits, and processed foods in general.

“Exchange white carbs for foods that release the sugar more slowly into the blood stream. Have brown rice instead of white rice, for example. The aim is to reduce the intake of refined sugars.”

Exercise is also quite important, because after exercise the body metabolises sugar more efficiently.

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“A combination of 30 minutes’ moderate walking per day and a healthy low-sugar diet would be enough treatment for 60-70pc of women with gestational diabetes,” says McAuliffe.

“There are some women who, despite cutting out all the sugar and exercising, will still need treatment,” she adds.

For the 30pc of women for whom a healthy diet and exercise won’t work alone, the Metformin tablets or insulin injections will be necessary. These are safe to take, as they won’t cross the placenta and affect the baby.

While the majority of women will revert to normal after pregnancy, some women will continue to have diabetes.

For women who get gestational diabetes, there is a 50pc chance they will develop type two diabetes later in life. However, the risk of developing it later can be reduced significantly by action taken during pregnancy. Eating healthily and exercising now will affect what happens in the future.


Prof Fionnuala McAuliffe is associate professor of obstetrics and gynaecology at the National Maternity Hospital Dublin and head of Women’s and Children’s Health at University College Dublin (UCD). She is also spokesperson for the Institute of Obstetricians and Gynaecologists.

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