Gestational diabetes explained: risk factors, testing and what happens next

A gestational diabetes diagnosis can feel like a shock, especially if you’ve done everything right. It’s common, it’s manageable, and most people with it have healthy pregnancies. Here’s what it is and what to expect.

What is gestational diabetes?

Gestational diabetes is a form of diabetes that can develop in pregnancy. The NHS says it happens when your body can’t make enough insulin to cope with the extra demands of pregnancy. Tommy’s says it affects about 1 in 20 pregnancies and usually goes away after the birth. It isn’t caused by anything you did. As Tommy’s puts it, anyone can develop it.

Who is more likely to get it?

The NHS lists these higher-risk situations:

being over 40
a BMI above 30
having had a baby weighing 4.5kg (10lb) or more
having had gestational diabetes before
a parent or sibling with diabetes
a South Asian, Black, African-Caribbean or Middle Eastern family background
weight-loss surgery such as gastric bypass

Having a risk factor doesn’t mean you will get it, and you can get it without any of them.

Symptoms

The NHS says it usually causes no symptoms and is found through screening. Thirst, needing to wee a lot, a dry mouth, tiredness and blurred eyesight can be signs, but they are also common in pregnancy anyway.

How it’s tested for

If your midwife thinks you’re at higher risk, you’ll be offered an oral glucose tolerance test (OGTT), usually between 24 and 28 weeks. If you’ve had gestational diabetes before, you’ll be offered a test earlier, soon after your booking appointment, and again at 24 to 28 weeks if the first result is normal. See everything you need to know before your gestational diabetes test.

How it’s managed

You’ll be given a kit to test your own blood sugar. The NHS says changing your diet and being more active, for example walking, swimming or prenatal yoga, come first. Tell your midwife before starting an activity you haven’t done before. If that isn’t enough, you’ll be offered tablets or insulin injections. Your team will talk you through this and your birth options.

What it can mean for your birth

The NHS says extra growth in your baby can make delivery harder and make induction or a caesarean more likely. It advises that it’s best to give birth before 41 weeks, with induction or a caesarean possibly recommended if labour hasn’t started by then. Earlier birth may be advised if there are other concerns or your blood sugar is hard to control. Tommy’s says most people with gestational diabetes have healthy pregnancies and healthy babies.

After your baby is born

The NHS says you should have a blood test to check for diabetes 6 to 13 weeks after giving birth, and then once a year if the result is normal. Having had gestational diabetes increases your chance of developing type 2 diabetes later, so a healthy weight, regular exercise and a balanced diet matter. See your GP if you have symptoms of high blood sugar without waiting for your next test.

If you had diabetes before pregnancy, see type 1 diabetes and pregnancy.

Questions people ask

Did I cause my gestational diabetes?

No. Tommy’s says it doesn’t mean you did anything wrong, and anyone can develop it.

Will it go away after the birth?

It usually does. You’ll still be offered a blood test 6 to 13 weeks after birth, and then yearly checks, because your chance of type 2 diabetes is higher.

Will I need insulin?

Not necessarily. Diet and activity come first, and the NHS says tablets or insulin are offered if that isn’t enough.

Can I still have a vaginal birth?

Many people do. The NHS says induction or a caesarean may be recommended in some cases, so talk through your options with your team.