Here is what mums asked our midwives this week: everything you need to know before your gestational diabetes test

This week a mum got in touch the night before her gestational diabetes test. She had lost her preparation letter, could not get through to the maternity ward and needed quick, clear answers. If this sounds familiar this blog post is for you.

What is the gestational diabetes test?

The gestational diabetes test ,also called the glucose tolerance test or GTT, is a blood test that checks how your body handles sugar during pregnancy. It measures your body's ability to maintain a normal blood glucose level and is routinely offered between 24 and 26 weeks of pregnancy. It may be offered earlier if you had gestational diabetes in a previous pregnancy.

Can I drink water during the fast?

Yes. You may drink clear unflavoured water only during your fast. Plain water is fine throughout both overnight and during the test itself. No tea, coffee, squash, juice or flavoured water.

What about food?

Do not eat or drink anything other than plain water for 10 to 12 hours before the test. Most hospitals ask you to stop eating from midnight the night before. You should eat normally for at least three days before the test, do not restrict carbohydrates in the lead up as this can affect your results.

Can I take my anti sickness medication?

As the midwife who answered this question advised, vomiting can affect the test result, so anti sickness medication is generally advised to still be taken. This is consistent with NHS guidance around medications and the GTT. That said, always confirm with your antenatal clinic on the morning of your appointment as individual advice may vary.

What happens on the day?

The test will take approximately 2.5 hours. When you arrive you will have a blood test taken first, this is your fasting sample. You will then be given a glucose drink to consume. Two hours later a further blood test will be taken. During this time you must not eat, but you can continue to drink plain water.

Bring something to keep you occupied: a book, headphones, your phone and pack a snack to eat straight after because you will be hungry.

What if I cannot get through to the maternity ward?

If you cannot reach the maternity ward directly, try calling your hospital's main number and ask to be put through to the antenatal clinic. If you have a community midwife contact number, try that too. If you are still unable to get an answer and you have specific concerns about medication, it is worth calling 111 for advice.

What happens after the test?

If you have an abnormal test result, a midwife will telephone you to inform you of the result and when to expect an appointment to attend the Gestational Diabetes clinic. If you do not hear back, your result is likely normal but do check with your midwife at your next appointment to confirm.

Got a question of your own?

Every week our midwives answer the questions mums are actually asking.Got a question of your own? Our midwives are available right inside the Dearbump app, ready to answer it directly.