What is gestational diabetes?
Gestational diabetes (GDM) is a type of diabetes that develops during pregnancy, usually during the second or third trimester. Our blood sugar levels are normally controlled by a hormone called insulin. Insulin allows the sugars (glucose) in our blood to enter our cells and fuel our bodies. Gestational diabetes develops when your insulin-producing cells can’t produce enough insulin; or, when the insulin you do produce does not work properly, also known as insulin resistance. This can lead to high blood glucose levels, which can cause serious health complications to you and your baby.
Testing
Gestational diabetes is usually tested at 24-28 weeks of pregnancy. An Oral Glucose Tolerance Test (OGTT) is used for diagnosis. This OGTT shows how your body responds to a specific amount of glucose over two hours.
If you had gestational diabetes in a previous pregnancy, it will be more likely the OGTT will be carried out at weeks 16-18 of pregnancy, along with a possible repeat OGTT at 28 weeks.
You are diagnosed with having gestational diabetes if your blood glucose level after the Oral Glucose Tolerance Test is either:
• Fasting is above 5.6mmol/L
• At two hours is above 7.8mmol/L
Who is more at risk?
You are more at risk of developing gestational diabetes if:
• you are overweight
• you have a family history of Type 2 diabetes
• you have had an unexplained stillbirth or neonatal death in a previous pregnancy
• you have had a very large infant in a previous pregnancy (4.5kg/10lbs or over)
• you have had gestational diabetes before
• your family origin is south Asian, black Caribbean, Middle Eastern or Hispanic
• you have Polycystic Ovarian Syndrome.
In most cases, gestational diabetes is temporary and blood glucose levels should return to normal after your baby is born. However, women with gestational diabetes have a 50% risk of developing Type 2 diabetes within five years.
You should be asked to repeat a test usually around six weeks after your baby is born.
How will gestational diabetes affect my baby?
It is important to control the level of glucose in the blood during pregnancy. If there is too much glucose in your blood, your baby’s body can start to make extra insulin to use the glucose.
Poorly controlled blood sugar levels can cause the baby to grow larger and can lead to difficulty during labour or complications during childbirth. It may increase the risk of pre-eclampsia. If your blood glucose levels are too high during pregnancy, your baby may have low blood glucose levels (hypoglycaemia) after birth, which may result in a longer hospital stay. Poorly controlled blood sugar levels during pregnancy may inhibit lung maturity and increase the chance of jaundice in your baby. There is also a slight increase in the risk of stillbirth.
Having gestational diabetes does not mean your baby will have diabetes.
What can I do to manage gestational diabetes?
Sometimes, changes in diet and lifestyle are enough to control blood glucose levels. Some women may need medication or insulin replacement to achieve good control.
Blood glucose testing
Testing your blood glucose regularly will help you understand how your levels are affected by different foods and portion sizes. Your GDM management will be guided by your blood glucose testing and therefore it is important that you monitor your blood glucose levels at least four times a day throughout your pregnancy:
- first thing in the morning, before you eat (fasting)
- one hour after breakfast
- one hour after lunch
- one hour after evening meal
Even though your blood glucose levels change during the day, there is a healthy range for these levels. Pregnant women who are on oral diabetes medications or insulin are advised to maintain their blood glucose levels above 4mmol/L at all times.
Suggested target ranges
| Time of reading | Blood glucose reading (mmol/L) |
| Fasting before mealtime | <5.3 mmol/L |
| One hour after meal | <7.8 mmol/L |
| Two hours after meal | <6.4 mmol/L |
Please note that your midwife or diabetes nurse may set different targets for you. It may be helpful to write down or record your levels throughout the day.
Weight gain with gestational diabetes
It is not necessary to ‘eat for two’ during pregnancy. Instead, the focus should be on achieving a healthy and consistent weight gain, which can be determined by your pre-pregnancy BMI. The table below serves as a reference for what constitutes healthy weight gain throughout pregnancy.
| Pre-pregnancy BMI | Healthy weight gain during pregnancy |
|
18.5 – 24.9kg/m2 (healthy weight) |
11.5 to 16kg |
|
25 – 29.9kg/m2 (overweight) |
7 to 11.5kg |
|
More than 30kg/m2 (obese) |
5 to 9kg |
Healthy eating with gestational diabetes
Making small changes to your diet and lifestyle can help you control your blood glucose levels. Your diet should be healthy and well balanced. Eat regularly, ideally three main meals daily e.g. breakfast, lunch, and evening meal. If you feel hungry or are taking insulin, you may need to plan for a small healthy snack between meals. It is not necessary to purchase ‘special diabetic food’. You can use the Eatwell Guide below to guide your food choices.
It will be helpful to cut down on sugary food and drinks. You can trial swapping these for more suitable foods, for example by using artificial sweeteners in place of sugar or honey, and swapping to diet, sugar-free or no-added-sugar beverages.
Your food choices with gestational diabetes
Try to follow the healthy portion plate to get the right balance at mealtimes.
You should aim to eat three main meals and two or more snacks every day. Spreading your meals and snacks out regularly throughout your day helps to keep your blood glucose levels stable.
- Fill half your plate with non-starchy vegetables. A portion of fruit may also be included in this part of the plate.
- Fill a quarter of your plate with whole grain products and starchy vegetables.
- Fill a quarter of your plate with protein foods.
- Hydration - choose water or a beverage with no added sugar.
The basics of healthy eating
Food consists of three main nutrients:
- carbohydrates – the main source of energy for our bodies (e.g., bread, rice, potatoes, etc.)
- proteins – which help build and repair your body’s tissues (e.g., meat, tofu, fish, etc.)
- fats – which provide energy and supports your body cells (e.g., butter, oils, etc.).
What should be included in my diet?
Starchy carbohydrates such as bread, rice, cereals, potato, and pasta are needed for energy, fibre, calcium, and iron.
Fruit and vegetables provide essential vitamins and minerals for you and your baby. Aim to have at least two portions of fruits and three portions of vegetables a day.
Protein foods such as meat, fish, eggs, beans, lentils, or protein alternatives are essential for the growth of your baby. Aim to include two to three portions a day.
Dairy foods and dairy alternatives such as milk, plant-based milk with added calcium, yoghurt, and cheese, are an excellent source of calcium, which is important for the development of bones and teeth. Aim to include two to three portions per day. Choose no added sugar and lower fat versions if you are trying to limit weight gain.
Fats: some fat in the diet is important. Aim for healthier options such as foods high in unsaturated fats (e.g., olive oil, rapeseed oil, sunflower oil, nuts, seeds, avocado). Limit the amount of saturated fat in your diet (e.g., full-fat dairy products, fatty meat, meat products such as sausages and bacon, biscuits, cakes, pastries, butter, cream, ghee, lard, coconut, and palm oils).
Added sugars are not essential to maintain a balanced diet and therefore should only be taken in small amounts.
Carbohydrate foods
Carbohydrates are necessary in the diet as they provide energy. It is important that you choose the right type and amount to improve your blood glucose control.
Choose wholemeal or wholegrain carbohydrates for your meals and snacks. These tend to release glucose more slowly and produce a smaller rise in blood glucose; they also keep you fuller for longer.
It is important to manage your carbohydrate portions - a large portion will raise you blood glucose. If you are having a bigger portion of carbohydrates, you may want to reduce the portion size and include more beans, lentils, pulses, vegetables, and salad instead. Try to adhere to the recommended portion sizes below.
Measuring your starchy carbohydrate portions
You should have a maximum of two portions of a starchy food at each meal or one portion of a starchy food for a snack.
|
Type of food |
Best Choice |
Recommended Portion Size |
|
Bread |
Seeded, multigrain, rye, wholemeal pitta, pumpernickel, granary, wholemeal chapati/roti (without ghee or oil), thepla, injera (with millet, wheat, or teff flour). Dosa, idli. |
1-2 slices of bread or 6-inch pita 1 thepla 1-2 small chapattis (e.g., Gujarati chapatis) or ½ large chapatti (e.g., Punjabi rotis) ½ naan |
|
Pasta |
Egg based pasta. Wholewheat/brown pasta. |
Cooked: 100 – 150 grams or 3 - 5 tablespoons. |
|
Rice |
Basmati, wild, brown, quinoa, bulgar wheat, pearl barley, red.
|
Cooked: 100 – 150 grams or 3 - 5 tablespoons. |
|
Potato |
Sweet potatoes, new potatoes, yam, cassava, plantain.
Fufu, eba, garri.
|
Cooked: 3-5 x egg-sized or 100-150g.
1 spoonful (40 grams)
|
|
Cereals |
Porridge (whole rolled/jumbo oats), shredded wheat, all-bran.
|
30 grams |
| Noodles | String hoppers (three-inch) | 2-3, cooked |
Other carbohydrate foods include sweets, desserts, and sugary drinks. These foods are high in sugar and will cause your blood glucose levels to rise quickly. Try to avoid these or opt for more suitable alternatives as below.
High sugar foods and lower sugar alternatives
|
High-sugar foods to limit |
Lower-sugar alternatives |
|
White sugar, brown sugar, gur, jaggery |
Artificial sweeteners e.g., Canderel, Sweetex, Splenda, Stevia*
|
|
Honey, syrup, lemon curd, treacle, condensed milk, chocolate and hazelnut spreads or biscuit spreads (e.g., Biscoff), jams, and marmalades.
|
Unsweetened nut butters and tahini. Puree fruit spreads. Reduced fat cream cheese e.g., Philadelphia Light, Dairylea.
|
|
Sweet biscuits e.g., custard creams, bourbon creams, chocolate digestives, Jaffa cakes, maamoul.
|
Plain biscuits e.g., rich tea, oat cakes. Ginger Nut. 2 squares of 70-80% dark chocolate.
|
|
Sweets and cakes e.g., mithai including Gulab jamun, laddu, barfi, jalebi. Timir cake, mandazi. Daheen, kunafa, zalabia. Black cake, coconut tart, plain cake. Baklava, tiramisu. Sponge cake, Bakewell tarts, sticky toffee pudding, minced pies. |
Try to limit your portion sizes of these and reducing how often you have them; you can try making your own versions and swapping to sugar-free sweeteners, semiskimmed milk, or unsweetened plant- based milks, and reducing ghee/butter.
|
|
Puddings e.g., kheer, halwa, zarda, Rasmalai, shahi-tukda, kulfi, cornmeal pudding, sweet potato pudding. Tinned fruit in syrup.
|
Sugar-free jelly, lower sugar custards, low-sugar rice puddings, sugar-free whips, and natural yoghurts. Chia seed puddings, fresh and/or frozen fruit in natural fruit juice, unsweetened apple sauce.
|
|
Sweet and full-sugar fizzy drinks e.g., meethi lassi, shikanjabeen, doodh |
Water and sparkling water, including sugar-free flavoured waters e.g., Volvic. |
|
pati/chai, Rabri doodh, falooda, doodh soda. Zobo drink. Mauby, Nurishment, sorrel, soursop drink, Supermalt. Coca-Cola, Pepsi, Fanta, Lucozade, lemonade, Sprite, Rubicon. Hot chocolate, malted milk drinks.
|
Unsweetened herbal teas. Diluted lemon or lime juices. Diet fizzy-drinks e.g, Diet Coke, Pepsi. No-added-sugar fruit squash. Home-made hot chocolate using unsweetened cocoa powder and sugarfree sweeteners. |
*It is safe to use artificial sweeteners in pregnancy, but some may have laxative effects, use these in moderation.
Fruit and vegetables
Fruit and vegetables contain vitamins, minerals, and fibre. Aim for at least five portions of fruit and vegetables per day: two portions of fruit, and at least three portions of vegetables. You can use the portion sizes for fruit and vegetables below as a guide; one portion contains roughly 15 grams of carbohydrates.
What is a portion of fruit or vegetables?
|
One medium sized fruit e.g., apple, pear, small banana, peach, or orange |
One slice of melon One slice of steamed breadfruit or CouCou/ cornmeal slice |
|
Small handful of grapes |
Large handful of berries e.g., blueberries, cherries (150 grams) |
|
Two small fruits e.g., kiwis, satsumas, plums |
Half grapefruit or mango, or half large banana |
|
Four fresh or dried apricots, prunes |
One cup of berries e.g., strawberries, raspberries (300 grams) |
|
Two to three tablespoons of vegetables e.g., broccoli, beetroot, aubergine, carrots, cauliflower (100 grams) |
One small bowl of salad |
|
Avoid fruit juices and smoothies, including fresh fruit juice |
Try to choose a variety of different fruits and vegetables each day – opt for fresh, tinned, or frozen varieties (be mindful of added ingredients such as sugar, salt, etc.).
Some people are concerned about having fruit because it contains sugar. Having too much fruit or too much fruit juice can affect your blood glucose levels. However, fruit can be a nutritious snack and contains vitamins and minerals which your body needs. Try to spread your fruit portion evenly across the day. Have one portion with your meal or as a healthy snack.
Protein
Protein is important for your baby’s growth. It is found in meat, poultry, fish, eggs, beans, dairy foods, soya products, dhal, Quorn, tofu, and nuts. These are also good sources of iron and minerals. Aim for two-to-three portions of protein foods per day - include these at each mealtime and aim for them to cover a quarter of your plate.
Choose lower fat proteins such as lean meat, remove skins and trim off visible fat when cooking. Aim to limit fatty or processed meats such as luncheon meat, sausage, salami, and processed ham.
You can use the portion sizes for protein below as a guide.
What is a portion of a protein food?
|
Tofu (200g before cooked)
|
One palm sized lean meat portion (100g before cooked)
|
|
1 lean lamb chop (100g before cooked)
|
1 tablespoon of nuts or seeds (25g) |
|
1 skinless chicken or turkey breast (125g before cooked)
|
1 white fish fillet (175g before cooked) |
|
3 fish fingers / 1 fish cake
|
2 eggs |
|
4 tablespoons of tinned beans, chickpeas, or lentils (150g)
|
2 tablespoons of dried beans, chickpeas, or lentils (50g) |
|
Quorn pieces/mince (150g) |
½ oily fish fillet (80g before cooked)*
|
|
2 sausages (125g before cooked)
|
1 tin of tuna in spring water (150g) |
|
2 rashers of bacon (75g before cooked)
|
Soya (100g before cooked) |
|
1 cup thick dahl |
1 and ½ cups of thin dahl
|
* Try to eat one portion of oily fish per week (maximum two portions per week)
It is important that you cook all meat, fish, and eggs thoroughly to ensure that all the bacteria are killed. There are certain protein foods you should avoid while you are pregnant as they can harm the baby:
- liver and liver products — these are too high in Vitamin A which can harm your baby
- raw shellfish
- raw egg
Milk and dairy products
Milk and other dairy products, such as cheese, contain proteins and vitamins and are an important source of calcium, which help to keep your bones, teeth, and muscles healthy.
When having dairy products, choose low-fat versions, such as semi-skimmed or skimmed milk, low-fat yoghurts, and reduced fat cheese if you are worried about managing your weight.
You should aim to have three portions of dairy products per day. You can use the portion sizes for dairy products below as a guide.
What is a portion of dairy foods?
|
200ml (1/3 pint) of milk
|
One pot of yoghurt (125 – 150 grams) |
|
150ml unsweetened lassi
|
3 tablespoons of cottage cheese (100 grams)
|
|
One matchbox-sized portion of cheese (30 grams)
|
30 grams of paneer cheese |
Try swapping traditional dairy foods, such as raita, condensed milk kheer or kulfi, for healthy options such as low-fat raita, kheer made with semi or skimmed milk, and shrikhand made with low-fat, Greek-style yoghurt.
There are some cheeses and milk you should avoid because they potentially contain harmful bacteria, including mould-ripened soft cheeses (such as Brie, Camembert and Chevre), soft, blue-veined cheeses (such as Danish Blue, Gorgonzola, and Roquefort), soft goats’ cheese, and unpasteurised milk.
Fat
Fat is found in oils, margarines, dairy foods, nuts, pastry, and meat. Some fat in the diet is important, but too much fat can lead to weight gain. A diet high in saturated fats can also lead to high cholesterol and an increased risk of heart disease. Reducing the amount of fat, you eat can help to prevent excessive weight gain during pregnancy. Aim to limit the fat in your diet to no more than three portions per day. You can use the portion sizes for fats below as a guide.
What is a portion of fat?
|
5 teaspoons low fat spread
|
5 teaspoons reduced fat mayonnaise |
|
2 teaspoons single cream
|
2 teaspoons mayonnaise / peanut butter |
|
2 teaspoon butter / margarine / oil / ghee / desi ghee / uncooked poppy seeds
|
4 teaspoons pesto |
|
2 teaspoons double cream or crème fraiche
|
¼ avocado (35g)
|
Other factors to consider
Some foods, especially when fried, combine high amounts of carbohydrate and saturated fat. For example:
- fried rice
- samosas
- onion bhajis
- masala curries
Look for lighter foods such as poppadums instead of naan. Curries such as bhuna or tandoori may be slightly better options for curry.
Fluids
It is important to drink plenty of fluid every day. You should drink 1500ml-2000ml (six-to-eight glasses) of fluid a day.
Tea and coffee can be included (without sugar), but it is also a good idea to include plenty of water in your diet as well.
It is advisable to limit caffeine to 200mg a day during pregnancy.
|
The amount of caffeine found in some foods and drinks |
|
|
1 mug of instant coffee |
100 mg |
|
1 mug of filter coffee |
140 mg |
|
1 mug of tea |
75 mg |
|
1 can diet cola |
40 mg |
|
1 can sugar free energy drink |
Up to 80 mg |
Salt
Too much salt in the diet may increase your blood pressure. It is easy to have too much, as it is present in many foods. Limit salt to a maximum of 6g a day.
To reduce your salt intake
- do not add salt to your food
- use less or no salt in cooking (use alternative seasonings, e.g., pepper, herbs, spices, onion, garlic, mustard)
- limit salty foods, e.g., Oxo, Bovril, sea salt, garlic salt, crisps, soy sauce o If you use a little salt while cooking, do not add any salt at the table. o Pickles and pappadums are high in salt – try to avoid these
- home-made chutneys and pickles like coriander/mint chutney, garlic and red chilli pickle or tomato chutney can be healthy accompaniments if prepared with minimal salt.
Snacks
If you are hungry between meals, you can have a small snack. You can consider some of these swaps.
|
Snacks to avoid/ limit |
|
Bhel puri Chevda, sev, gathia, dal moth, crisps Potato vada, pakoras, samosas Fried moong Dal vada Fried papad Fried salted nuts Biscuits, cakes, mithai |
|
Healthier swaps |
|
Plain puffed rice with spices Chevda made with one part Chevda mix and three parts puffed rice and spices. Dry roasted chickpeas Roasted corn on the cob Boiled potato chaat One small samosa baked in the oven or one small vegetable pakora Baked crisps Popcorn (unsalted) Microwave or grilled papad Handful of mixed unsalted nuts Fresh sprouted moon beans Dhokla, Handvo Fruit chaat Oatcakes, rye-based crackers, or sliced vegetables with tomato salsa or cottage cheese Two boiled eggs One apple and one teaspoon peanut butter Sugar-free jelly one cheese straw |
Glycaemic Index (GI)
The glycaemic index (GI) tells us whether a food raises blood glucose levels quickly, moderately, or slowly. This means it can be useful to help you manage your diabetes.
Different carbohydrates are digested and absorbed at different rates, and GI is a ranking of how quickly each carbohydrate-based food and drink makes blood glucose levels rise after eating them.
The GI ranges from 0 to 100, with pure glucose (sugar), which has a GI of about 100, typically used as the reference. Carbohydrates that are absorbed slowly have a low GI (55 or below), and these include most fruits and vegetables, unsweetened dairy, nuts, legumes, and some wholegrain cereals and bread.
Not all low-GI foods are healthy. For instance, many chocolates have a low GI due to their high fat content, which slows carbohydrate absorption.
Managing your diabetes isn’t just about focusing on GI values. It’s important to consider the overall picture and choose foods rich in fibre and whole grains, while being low in saturated fat, salt, and sugar, as part of a balanced, long-term healthy diet.
Understanding food labels
Looking at, reading, and understanding food labels can help you guide your food choices. When reading food labels, always look at the ‘per 100g’ of food column.
Try to choose foods with:
- less than 5g of sugar per 100g for a low sugar option
- more than 6g of fibre per 100g for a high fibre option (these foods keep you full for longer)
Some products have green, amber, or red traffic light colours on the front of their packs. This is to help you see at a glance if the food has low, medium, or high amounts of fat, saturated fat, salt, and sugar.
| High | Medium | Low | |
|
Fat |
More than 17.5g |
3.1g-17.5g |
3g or less |
|
Saturated Fat |
More than 5g |
1.6g-5g |
1.5g or less |
|
Sugar |
More than 22.5g |
5.1g-22.5g |
5g or less |
|
Salt |
More than 1.5g |
0.31-g1.5g |
0.3g or less |
Green indicates that the food is low in calories, fat, sugar, or salt and is a healthier choice.
Amber indicates that the food has a medium amount of calories, fat, sugar or salt, so this is an ‘ok’ choice, but be careful with the quantity eaten.
Red indicates that the food is high calories, fat, sugar, or salt, so these foods should only be eaten occasionally or in small amounts.
Other helpful resources
https://www.diabetes.org.uk/diabetes-the-basics/gestational-diabetes
https://heal-d.org/wp-content/uploads/2023/03/heal-d-helping-hands-portion-size.pdf
https://www.heartuk.org.uk/healthy-diets/south-asian-diets-and-cholesterol