Unsure what is gestational diabetes or more properly gestational diabetes mellitus (GDM) is? Looking to understand how you can help with changes to your diet? Read on to find out how to find the answers, learn practical tips for improving your diet, how to reduce your risk of developing type 2 diabetes and how to improve your sugar levels with food.
What is Gestational Diabetes Mellitus?
GDM is high blood sugar (glucose) that develops during pregnancy and for most women, gets better after giving birth. Less that 1 in 5 women are affected by GDM.
While it can happen at any stage of pregnancy, it is more common in the second and third trimester.
GDM occurs when your body is unable to produce enough insulin, (a hormone that controls blood sugar levels), to meet your extra needs in pregnancy.
While it is possible to improve your sugar levels with food, for some people this is not enough, and medications are needed.
Who is at risk of Gestational Diabetes?
While any woman can develop GDM during pregnancy, you are at greater risk if:
- your body mass index (BMI) is > 30
- you have had GDM in a previous pregnancy
- one of your parents or siblings has diabetes
- you have previously had a baby who weighed 4.5Kg (10lb) or more at birth
- you are of Black, Afro-Caribbean, Middle Eastern or south Asian origin, regardless of where you were born.
If any of these apply to you, discuss screening for GDM with your midwife.
Symptoms of Gestational Diabetes
For most women, GDM doesn’t cause any symptoms, which makes screening important to test your blood sugar levels and diagnose GDM.
However, some women may get symptoms if their blood sugar gets too high (hyperglycaemia) such as:
- feeling tired
- an increased thirst and drinking more than usual (polydipsia)
- needing to pass urine more often (polyuria)
- a dry mouth
Even in normal pregnancies, some women experience some of these symptoms, which are not necessarily a sign of GDM. Therefore, if you are concerned about any symptoms that you are experiencing, it’s best to speak with your midwife or doctor.
Screening for GDM
Your midwife or doctor will ask you questions to determine your risk of developing GDM during your first appointment (also called booking appointment). If you are at increased risk you will be offered an oral glucose tolerance test (OGTT), that takes about 2 hours.
It involves having a fasting blood glucose level, where you have not had any food or drink for 8 to 10 hours. Then after a glucose drink at the hospital, another blood sample is taken two hours later.
How Does Gestational Diabetes Affect Pregnancies
While most women with GDM have otherwise healthy pregnancies, for some women, GDM can cause problems such as:
- your baby growing larger than usual (macrosomia). This can increase the risk of your baby getting stuck, and need for an instrumental delivery or a caesarean section.
- too much amniotic fluid (polyhydramnios), that can cause premature labour or problems at delivery
- premature birth before the 37th week of pregnancy
- elevated blood pressure (pre-eclampsia) that can lead to other significant complications if not treated
- increased risk of your baby developing jaundice that may require treatment
- rarely, the loss of your baby (still birth).
Changing Your Diet and Lifestyle
In order to protect your baby, and your long-term health it is important to keep your blood sugar levels stable between 4-7mmol. Changing your diet to make healthier choices and ensuring you do regular exercise will help you to attain a healthy weight and keep your blood sugar in the normal range.
During the first two trimesters of your pregnancy, you don’t need any extra calories. Instead beware of the myth of ‘eating for two’ since this can affect your portion size and blood sugar level. During the third trimester, you may need an additional 200 calories per day, which is the equivalent of a small yoghurt or half a sandwich.
How to Improve Your Sugar Levels With Food
Many people find that reducing sugary foods and portion control can play a big role in controlling your blood sugar.
Ultimately the best way to attain a healthy weight is by regular exercise and a healthy diet that follows these principles:
- eat lots of different coloured fruit and vegetables (50% of your plate)
- choose whole grains (bulgur wheat, teff, millet, brown rice, brown bread) (25% of your plate – or the size of your fist)
- chose lean or plant-based protein (25% of your plate)
- eat a handful of nuts a day and add seeds to your food
- drink water
- eat oily fish once a week
- enjoy healthy unsaturated fats such avocados, rapeseed and extra virgin olive oils.
- support your microbiota to flourish by eating 30g of fibre a day and fermented foods, such as kimchi and kefir.
All carbohydrates affect your blood sugar levels, but healthier wholegrain ones, are broken down more slowly (low glycaemic index), and so have less impact on your blood sugar.
During a day aim to have the following:
- at least 5 portions of a variety of fruit and vegetable (a portion is the size of your palm)
- 2 lean non dairy protein portions such as
- 60-90g (size of a pack of cards) of cooked lean meat
- 140g cooked oily fish (palm size) – aim for 1 portion per week
- 140g cooked fish (palm sized)
- 2 eggs
- 4 tablespoons / 100g of tofu
- 1 tablespoon / 30g of nuts or nut butter
- 4 heaped tablespoons / 150g of cooked pulses and beans
- 1 portion of wholegrain carbohydrate at each meal
- 1 slice of bread
- 2-3 tablespoons of cooked pasta
- 2-3 tablespoons of cooked rice
- 1 medium baked potato with skin
- 2 egg sized new potatoes (boiled)
- 3 tablespoons of porridge oats
- 3 portions of dairy or calcium rich foods per day
- 1 glass of milk or fortified unsweetened plant based alternative (200mls)
- 1 small pot of yoghurt or fortified unsweetened plant based alternative (125mg)
- 1 matchbox sized piece of hard cheese (30g) or 2 matchbox sized (80g) pieces of soft cheese
Try to choose:
- healthy unsaturated fats such as olive oil, rapeseed oil, or avocado oil instead of saturated fats such as butter
- lean protein sources such as plant sources, fish, or poultry instead of red meat
- water instead of sugary drinks and dilute fruit juice 1:10 to water
- fruit as a desert
Try to avoid:
- sugar in hot drinks
- energy drinks
- processed food like cakes, chocolates, ice cream and biscuits.
- sugar can be added to foods in a variety of formats so know what to look for and avoid
- invert sugar
- corn sweetener
- fried food, try to poach, steam or grill instead.
- low fat food often contains sugar instead to make it more palatable, which is more likely to affect your blood sugar.
You will be closely monitored during pregnancy and birth, and if your blood sugar levels are not driven down into the normal range by changes to your diet, then you might need medication as well.
How Exercise Can Help Gestational Diabetes
If you are already active during your pregnancy, then it is safe to maintain your exercise levels, but try not to do more than before. If you are able to exercise, aim to help control GDM and reduce your future risk of type 2 diabetes by fitting in per week:
- 150 minutes of moderate intensity activity or 75 minutes of vigorous intensity
- 2 sessions of resistance training or muscle strengthening exercise.
Summary of Gestational Diabetes
I hope this article has helped you understand what gestational diabetes is, and how to improve your sugar levels with food. Making these changes may help reduce your longer term risk of type 2 diabetes as well.
For further information about what to eat during pregnancy, download my free pregnancy meal planner and nutrition checklist and see my book “Eating During Pregnancy“.