Gestational diabetes risk factors: who is more likely to get it and what lowers the chance

What gestational diabetes is

Gestational diabetes is a type of diabetes that develops during pregnancy, when blood glucose, also called blood sugar, is too high (NIDDK). It happens when the body can't make the extra insulin needed during pregnancy. Hormones and other changes such as weight gain make the body's cells use insulin less well (insulin resistance); most pregnant women can make enough insulin to overcome it, but some cannot (NIDDK). Researchers think it is caused by the hormonal changes of pregnancy along with genetic and lifestyle factors (MedlinePlus).

It affects an estimated 5.8% to 9.2% of pregnancies in the US (USPSTF 2021). Anyone who is pregnant could develop it (MedlinePlus).

Risk factors that raise the chance

• Overweight or obesity. Women who are overweight or have obesity may already have insulin resistance when they become pregnant (NIDDK) (NIDDK).
• Gaining too much weight during pregnancy, especially too quickly, may also be a factor (NIDDK) (NIDDK).
• Gestational diabetes in a past pregnancy (NIDDK) (MedlinePlus).
• Prediabetes, meaning blood glucose levels higher than normal but not high enough for a diagnosis of diabetes (NIDDK).
• Family history. A parent, brother or sister with type 2 diabetes (NIDDK). A family history of diabetes suggests genes play a role (NIDDK).
• Polycystic ovary syndrome (PCOS), a hormonal disorder (NIDDK) (MedlinePlus).
• A past baby weighing 9 pounds or more (MedlinePlus).
• Older age. The USPSTF lists increased maternal age as a risk factor, and age younger than 25 to 30 years among the factors linked to a lower risk (USPSTF 2021).
• Race and ethnicity. NIDDK lists African American, American Indian, Asian American, Hispanic/Latina and Pacific Islander American women (NIDDK). MedlinePlus also names Alaska Native and Native Hawaiian people (MedlinePlus). The USPSTF notes that the differences between groups may be due in part to social risk factors such as low socioeconomic status or structural racism (USPSTF 2021).

Higher BMI raises the risk across racial and ethnic groups, but the link varies. In Asian American people, gestational diabetes is about as common at a BMI of 22 to less than 25 as it is at a BMI above 28 in Hispanic, non-Hispanic White and Black people (USPSTF 2021). You can check your BMI with the BMI calculator.

Which ones you can change

If you are thinking about becoming pregnant and are overweight, losing extra weight and being more physically active before pregnancy can lower your chance of gestational diabetes (NIDDK). Being physically active before and during pregnancy also may help (NIDDK). Once you are pregnant, don't try to lose weight: you need to gain some weight for your baby to be healthy. Ask your doctor how much weight gain and physical activity are right for you (NIDDK).

When testing happens

Gestational diabetes usually has no symptoms. If there are symptoms, they may be mild, such as being thirstier than normal or urinating more often (NIDDK). That is why testing matters.

Testing usually happens between 24 and 28 weeks of pregnancy. If you have an increased chance of gestational diabetes, your doctor may test for diabetes at the first visit after you become pregnant (NIDDK). The USPSTF recommends screening at 24 weeks or later (USPSTF 2021). The tests are the glucose challenge test, the oral glucose tolerance test (OGTT), or both (NIDDK). In the glucose challenge test, blood is drawn 1 hour after a sweet drink, without fasting. A result of 140 or more may mean you need an OGTT, and 200 or more may mean type 2 diabetes (NIDDK). The gestational diabetes screening check explains the steps in more detail.

Why it matters for you and your baby

High blood glucose during pregnancy can lead to a baby who is born too early, weighs too much, has low blood glucose or breathing problems right after birth, and raises the chance of miscarriage or stillbirth (NIDDK). It makes preeclampsia and a C-section more likely (NIDDK).

What it means for type 2 diabetes later

Gestational diabetes usually goes away after the baby is born, but you will be at higher risk of type 2 diabetes later (MedlinePlus). Your baby will also be more likely to become overweight and develop type 2 diabetes as they get older (NIDDK).

NIDDK advises a diabetes test no later than 12 weeks after the baby is born, and then every 3 years even if the result is normal (NIDDK). MedlinePlus says testing happens within 4 to 12 weeks after birth and then every 1 to 3 years (MedlinePlus). Ask your provider which schedule fits you.

To lower your risk afterwards, NIDDK suggests being more active and making healthy food choices to get back to a healthy weight, and breastfeeding. If you are overweight and your test shows you could get diabetes, your doctor may suggest weight loss help or a medicine such as metformin (NIDDK). See type 2 diabetes risk factors and the diabetes risk test, which asks about gestational diabetes.

Common questions

Can I get gestational diabetes with no risk factors?

Yes. Anyone who is pregnant could develop it (MedlinePlus), which is why testing is done during pregnancy.

Will I have symptoms?

Usually not, or only mild ones such as more thirst or urinating more often (NIDDK).

If my test after birth is normal, am I in the clear?

Not fully. You still have a greater chance of type 2 diabetes in the future, so regular testing is advised (NIDDK).