Gestational diabetes mellitus (GDM)

If you have gestational diabetes mellitus, you may be at risk of:

• having a large baby, which increases the likelihood of birth problems, such as shoulder dystocia
• having your labour induced and caesarean section
• developing Type 2 diabetes.

Your baby may be at risk of:

• health problems following birth that may require hospital care/ neonatal admission
• stillbirth
• being at greater risk of developing obesity and/or diabetes in later life.

Upon diagnosis of gestational diabetes, you will be asked to make changes to your diet and lifestyle. The Diabetic Team will arrange a telephone review in around two weeks to assess your management for the rest of the pregnancy.

During your pregnancy, your healthcare professionals will give you information and advice about:

• planning birth, including timing and types of birth, pain relief and changes to your medications during labour and after your baby is born
• looking after your baby following birth
• care for you after your baby is born including contraception
• possible induction of labour or Caesarean section if appropriate at 39-40 weeks for those on treatment, or 40-40+6 for those who are diet-controlled

Healthy eating in pregnancy

The most important treatment for gestational diabetes is a healthy eating plan and exercising regularly. Walking for 30 minutes after a meal can help with controlling your blood glucose levels. Gestational diabetes usually improves with these changes. You should have an opportunity to talk to a healthcare professional about choosing foods that will help to keep your blood glucose at a healthy and stable level. 

If you consent, you will be referred to the dietician and a teaching session will be arranged to discuss in more depth healthy eating and nutrition.

Management of GDM

The specialist midwife will discuss an individual plan of healthy eating and lifestyle. A dietician referral is also offered. You will be shown how to monitor your blood glucose levels at home and have regular reviews with the specialist midwife and Obstetric Team. Your care pathway will be transferred to consultant-led management.

If your blood glucose levels cannot be controlled by diet and exercise alone you may require medication. Depending on your diabetes control, the Diabetic Team will review your blood sugars up to three times a week.

Up to 50% of women with GDM will require medication in their pregnancy. Regular growth scans and review of blood sugar control will aid you and the obstetric team to plan a safe birth for your baby. 

A planned birth at 39-40+6 weeks' gestation will be discussed with the obstetric consultant.

Monitoring GDM

We will provide you with a blood glucose monitor and teach you how to use it. You will need to test your blood four times a day. Aim to keep blood glucose levels between:

•  4-5.3 mmol fasting (before breakfast) 
• 4-7.8 mmol one hour after main meals (breakfast, lunch and dinner)

Record all your blood glucose readings- If you are connected to the ‘Mysugr’ app, your blood sugar readings will be transferred via Bluetooth to an online platform where you and health professionals can view them. If we are unable to connect you, we will give you a document to write them down manually. Please ensure you bring this document to all appointments for health professionals to review.

Monitoring and prescriptions

A GP letter will be given to you at the time of your teaching session for the equipment used to test your blood sugars. Please ensure you take this letter immediately to your GP, in order that you will have sufficient supplies to monitor at home. The letter is a repeat prescription, therefore please call your GP for a repeat prescription when your supplies are low. Please ensure you have enough supplies if admitted to hospital, as the ward do not supply strips and needles for testing.

Metformin

The first line treatment is Metformin instant release tablet (IR). Slow release Metformin (Metformin SR) may be offered if you are unable to tolerate Metformin IR or as trial to stabilise fasting blood sugars. The maximum dose of Metformin is 2g daily in divided doses.

If prescribing Metformin to a patient, please issue a GP letter/request to continue supply after 30 days, and allow two weeks to assess if metformin treatment is improving blood sugar ranges. However, if indicated, recommend insulin therapy sooner as a second line of treatment.

Insulin

The most common insulin products used in pregnancy are:

Novorapid Flexpen

Given before mealtimes; the starting dose is normally two units and can be increased weekly if indicated

Humulin I Kwikpen

Given before bed, the starting dose is normally two units and titrated as indicated

Insulin can be increased every three days if blood sugar ranges are significantly high. If unsure please liaise with DSM/DSN for further input and advice.

Some pre-existing diabetic patients may be on other insulin injections such as Levemir, Humalog, Insulatard, Lanctus etc.

View media

View media

Other useful information 

For more information about diet, visit:
Diabetes UK: Gestational diabetes diet 
NWL Know Diabetes Diabetes in North West London

During your first antenatal appointment, your midwife will ask you some questions to determine whether you are at an increased risk of gestational diabetes. 

Risk factors include: 

• Family history of diabetes (first degree relative with diabetes)  

• BMI of 30 or more 

• You previously had  a baby who weighed 4.5kg or more at birth 

• Previous stillbirth 

• Family origin with high prevalence of diabetes such as:  

• South Asian (specifically women whose country family origin in India, Pakistan or Bangladesh) 

• Black Caribbean 

• Black African 

• Middle Eastern (specifically women whose country of family origin is Saudi Arabia, United Arab Emirates, Iraq, Jordan, Syria, Oman, Qatar, Kuwait, Lebanon or Egypt) 

•  Oriental 

If you have or one or more risk factors for gestational diabetes you should be offered a screening test. 

The screening test is called oral Glucose Tolerance Test (GTT), which takes about two hours in total. 

A GTT is done between 25+5-28 weeks pregnant. If you have had gestational diabetes before, you will be offered screening earlier in pregnancy. This is usually within 2-3 weeks from your booking appointment and then another GTT at 25+5-28 weeks if the first test is normal. 

A GTT may also be offered to you if there is a significant amount of glucose detected in your urine sample, which is tested at each antenatal appointment by the midwife or doctor. 

How to prepare for a GTT

You should be fasting on the day of your test. This means no food or drinks, except sips of water from midnight, are allowed. 

There are three parts to your blood test

1. A fasting blood test will be taken. A glucose drink will be given straight after and you must drink ALL of it within 5 minutes. The recommended glucose drink given at the time of a GTT is called Polycal. This is a 75 g glucose load (113mls) mixed with 150mls water. 
2. You will then need to wait two hours for the second blood test in order to complete the glucose tolerance screening. Once your fasting glucose is done and if possible, please vacate the antenatal clinic. Make sure you return 10 minutes before your second blood test. If you are late we will need to rebook your test. 
3. In the two-hour wait you must not eat anything (including chewing gum) or perform exercise (running or a walk of more than 10 minutes) as this will affect your result and may require a rebooking of your test.  Sips of water are allowed  

Results

Results are checked the following day by the diabetic midwives. 

If your result is abnormal, an appointment letter will be sent to you to attend a group teaching session for those with gestational diabetes, within 7-10days of your test. If your result is significantly high, you will be called to attend an urgent appointment and teaching of gestational diabetes. 

What if I do not attend my appointment? 

If you are unable to attend your appointment please call the antenatal clinic on 01895 279442 to rebook your appointment at a later date or send an email to: thh.antenatalenquiries@nhs.net  

If you do not attend your first appointment, the antenatal clinic will automatically rebook your appointment. However, if you do not attend the second appointment you will not be offered any further appointments for a GTT.