Tommy's PregnancyHub

Taking medication and insulin for gestational diabetes

Some women can control their glucose levels through diet and exercise alone, but others will need to take tablets or injections to help control it.

If you have gestational diabetes, the chances of having problems during your pregnancy can be reduced by avoiding too much weight gain and aiming to keep your glucose levels in the target range. You can do this by making changes to your diet and exercise routine. If these changes don’t lower your glucose levels enough after 1 to 2 weeks, you may be given tablets or insulin.

You may also be given medicine straight away after you’ve been diagnosed with gestational diabetes if:

  • your glucose levels are very high
  • your baby is growing larger than normal (macrosomia) or there it too much amniotic fluid surrounding the baby (hydramnios).

"If I’d understood more about it, I’d have stuck with the diet and found ways to lower my glucose levels. Having insulin is not just a quick fix so that you can eat what you want." 


Up to 1 in 5 women with gestational diabetes will need to take tablets or have insulin injections to control their glucose during pregnancy. Your healthcare team will advise you what treatment is best for you.


Metformin is taken as a tablet. It makes your body respond better to insulin, which is the hormone that lowers the level of glucose in your blood.

There are some common side effects of metformin. These can include:

  • feeling sick
  • being sick
  • stomach cramps
  • diarrhoea
  • loss of appetite.

Starting on a low dose (just 1 tablet) and increasing the dose slowly will reduce these side effects. Taking the tablet with or after meals can also help. Talk to your healthcare team if you have any concerns.


You may be offered insulin if:

  • you can’t take metformin or it causes side effects
  • metformin isn’t controlling your glucose levels
  • you still have high glucose levels despite taking a full dose of metformin (usually two 500mg tablets twice or three times daily)
  • your baby is growing larger than normal (macrosomia) or there it too much amniotic fluid surrounding the baby (hydramnios).

Insulin is taken as an injection, which your diabetes team will show you how to use by yourself. They’ll also tell you:

  • when to inject yourself (for example, when your wake up, at bedtime or before meals)
  • where to keep your insulin
  • where to put the used needles.

Try not to worry if you don’t like needles. Insulin injections are not like injections that you may have had in the past. The needle is very fine, so you’re unlikely to feel it. Plus, insulin is injected just underneath the skin, rather than into a muscle, so it doesn’t go in deeply.

Find out more about gestational diabetes and injecting insulin.

"It’s amazing, the needle itself is tiny – you don’t feel it at all. It was straightforward, though you always have to find somewhere to do it – a loo or something." Katie, mum of two


Insulin can sometimes cause your glucose levels to fall too low, which is known as hypoglycaemia. Your team will explain how to treat hypoglycaemia with 10-15 grams of fast-acting carbohydrate if this happens.

Find out more about hypoglycaemia.

After your baby is born

You’ll probably be advised to stop taking your diabetes medication straight away after your baby is born. This is because gestational diabetes usually gets better after birth.

Diabetes and driving

If you are taking anything for your diabetes you will need to check the rules from the Driver and Vehicle Licensing Agency (DVLA) in England, Scotland and Wales, and the Driver and Vehicle Agency (DVA) in Northern Ireland.

This is because of the risks associated with low glucose levels. You may also need to tell your car insurance provider.

NICE (2015). Diabetes in pregnancy: management from preconception to the postnatal period. National Institute for health and care excellence

Royal College of Obstetricians and Gynaecologists (2013) Gestational diabetes

NHS Choices. Metformin. (Page last reviewed: 08/02/2019. Next review due: 08/02/2022)

NHS Choices. Treatment for gestational diabetes. (Page last reviewed: 06/08/2019. Next review due: 06/08/2022)

Review dates
Reviewed: 24 July 2020
Next review: 24 July 2023

This content is currently being reviewed by our team. Updated information will be coming soon.