Gestational diabetes FAQs

Gestational diabetes is diagnosed using an Oral Glucose Tolerance Test (OGTT). This is done at a pathology lab. You will need to fast overnight before this test.

Blood will be taken to check your fasting blood glucose level. After this, you will be given a sugary drink and have your blood tested one and two hours later. You will be asked to sit and wait between tests.

If your blood glucose level is above the normal range at your fasting, one- or two-hour test, you have gestational diabetes.

All pregnant women should be tested for gestational diabetes. This is usually done between 24 and 28 weeks of pregnancy (except those women who already have diabetes). However, it may be done earlier for women who may be at risk.

During pregnancy, some of the hormones produced by the placenta (which provides nutrition for the growing baby), reduce the action of the mother’s insulin. This is called insulin resistance. When insulin resistance occurs, the pancreas then needs to produce extra insulin to keep blood glucose levels in the normal range. If the pancreas is unable to produce enough insulin, blood glucose levels rise and gestational diabetes develops.

For most women, diabetes disappears after pregnancy; however, there is an increased risk of future diabetes.

15% of all pregnant women develop gestational diabetes; however, the incidence is higher in certain ethnic groups.

Maintaining a healthy lifestyle before pregnancy can help to reduce the risk of developing gestational diabetes. This includes aiming to be as close to the healthy weight range as possible, making healthy food choices and being active every day.

For most women, diabetes disappears after the baby is born.

However, as many as 1 in every 5 women with gestational diabetes will continue to have high blood glucose levels after their baby is born. For this reason, a follow-up oral glucose tolerance test (OGTT) is recommended 6–12 weeks after the baby is born (or as soon as possible after this time) to check the blood glucose levels have returned to the normal range.

Women who have had gestational diabetes are at an increased risk of developing type 2 diabetes later in life with approximately 1 in every 2 women developing pre-diabetes or type 2 diabetes within 10–20 years.

If blood glucose levels are high during pregnancy, excess glucose passes through the placenta to the baby, who then makes extra insulin.

This can make the baby grow too big, which can cause problems during labour and increase the risk of early delivery or the need for a caesarean section.

After the birth, the baby may have a greater risk of low blood glucose levels (hypoglycaemia). This is because the baby is no longer receiving extra glucose from their mother, but they continue to make more insulin than a baby usually would, causing their blood glucose levels to drop.

Women with gestational diabetes are also at greater risk of developing high blood pressure and pre-eclampsia (high blood pressure, protein in the urine and fluid retention or swelling) during pregnancy.

Well-managed gestational diabetes reduces the risk of these health problems for mother and baby. Your doctor and a team of diabetes health professionals can work with you to help keep your blood glucose levels within the target range to provide the best outcome for both you and your baby.

Most women with gestational diabetes will have a healthy pregnancy and a healthy baby.

No. Gestational diabetes will not lead to your baby being born with diabetes.

Babies born to mothers who have had gestational diabetes however, may be at increased risk of childhood obesity and type 2 diabetes later in life. It is recommended that the whole family eat well and stay active to reduce this risk.

Most women will no longer have diabetes after the baby is born. However, some women will continue to have high blood glucose levels after delivery. An OGTT is very important to check that blood glucose levels have returned to normal. You will be advised to have this test 6–12 weeks after your baby is born (or as soon as possible after this time).

You should continue to be checked for type 2 diabetes every 1–3 years. Your GP will advise you on the type of test and how often you need to have this done. This will depend on your risk factors for type 2 diabetes, the results of previous tests and whether you are wanting to have any more pregnancies.

Breastfeeding is recommended for all women, including women with gestational diabetes. Breastfeeding provides the best start for your baby and has many benefits, both for you and your baby. These include benefits for your baby’s immune system, growth and development, and it can help with bonding between you and your baby. Breastfeeding has also been shown to have long-term health benefits for mother and baby, including reducing the risk of future type 2 diabetes.

Current guidelines recommend exclusive breastfeeding to around 6 months of age (when solid foods are introduced), then continued breastfeeding until 12 months of age or beyond. Studies have shown the longer you breastfeed, the lower your risk of future type 2 diabetes.

Women with gestational diabetes who register with the NDSS automatically have their details added to the National Gestational Diabetes Register. If you do not want to be part of this register, use the online form to be removed, or call the NDSS Helpline on 1800 637 700 to opt-out.

If you decide to opt-out, you will lose the benefits of being on the Register, and you and your GP will no longer receive reminders about diabetes checks or information to help you maintain a healthy lifestyle.