Updated: Mar 12
Gestational diabetes is when a woman develops blood sugars high enough to be defined as diabetes during pregnancy. Blood sugars usually return to normal after birth.
It can occur at any stage during a pregnancy but it usually occurs in the second or third trimester. Gestational diabetes may cause symptoms such as increased thirst, a dry mouth, tiredness or needing to urinate more often than normal. However, some women do not experience symptoms at all, and this is why screening for the condition is so important. In the UK, women are screening for gestational diabetes at their first antenatal appointment at around 8-12 weeks pregnancy.
What are the potential risks of gestational diabetes?
It’s important to note that most women with gestational diabetes have pregnancies which are completely normal and deliver perfectly healthy babies. However, gestational diabetes can cause some problems such as larger babies - this can increase the risk of needing induced labour or caesarean section. Gestational diabetes can also increase the risk of other complications such as pre-eclampsia (which is high blood pressure during pregnancy) or premature birth.
The good news is that with screening - the right treatment, guidance and support can be offered to help women with gestational diabetes keep their blood sugars from becoming too high.
Can diet help me with managing my gestational diabetes?
Yes! Diet can definitely influence blood sugars so simple changes can help keep blood sugars under control. Moderate reduction in processed starchy carbohydrates (like white bread, white rice or sugary cereals) and/or switching to “intact” grains such as brown rice, quinoa, or more slowly digestible carbohydrates can help.
It’s also important to note that traditional advice to “eat for two” is actually not supported by the scientific evidence at all. The Royal College of Obstetricians and Gynaecologists has clarified that extra calories is only needed in the final 12 weeks of pregnancy.
But remember - be kind to yourself! Pregnancy is a tough time for many reasons - your hormones are all over the place, your sleep may be affected, you might be very tired and have nausea and vomiting as a result of the pregnancy. So pregnancy is (more than ever) a time to acknowledge that you are doing the best that you can!
People can get remission of their type 2 diabetes with meal replacements or low-carbohydrate diets. Do you recommend these approaches in gestational diabetes?
It’s important to note that dietary changes which might be recommended for managing diabetes in women who are not pregnant are not necessarily appropriate for women with diabetes who are pregnant. Intentional weight loss is not recommended during pregnancy. Therefore a meal replacement plan aimed at achieving weight loss to get remission of diabetes should not be attempted during pregnancy.
Many women report being able to manage their gestational diabetes with low-carbohydrate diets during pregnancy. There is also some anecdotal data in the scientific literature that this can be an effective approach at managing gestational diabetes. However, it is important to note that the quality of the data is not very strong in gestational diabetes.
While it might seem intuitive that consuming a low-carbohydrate diet would improve blood sugars in diabetes, the evidence to support this is actually not that strong. In one randomised controlled trial, insulin requirements in women with gestational diabetes were not different between pregnant women with gestational diabetes consuming low- or high carbohydrate diets.
It is also important to note that low or very low carbohydrate diets can cause an increase in free fatty acids circulating in the blood. These free fatty acids come from dietary fat or from adipose tissue (ie fat stored in our bodies) and they can be burned for energy. The concentration of free fatty acids in the blood can increase 4-fold when a person reduces their carbohydrate intake. In a non-pregnant state this is not harmful at all (so far as we know, and could even have some benefits). However, free fatty acids do act as signaling molecules (basically they can instruct cells to make certain hormones or enzymes) and it is unknown whether this could have unknown consequences during pregnancy. Pregnancy and infancy are periods of rapid growth for a human and nutrition during this stage of the lifecourse may have vastly different consequences than for an older adult.
Therefore, my advice is that until we have better data on the role of low-carbohydrate diets (as opposed to moderate reduction of carbohydrate portion size) in the management of gestational diabetes, to keep with moderation during this unique time.
My doctor has recommended I take medications for my gestational diabetes, but I want to manage it with diet alone. What shall I do?
One of the challenges of managing gestational diabetes is that many of the more *dramatic* options such as meal replacement, low-carbohydrate or ketogenic diets may not be appropriate or may be contraindicated during pregnancy. Therefore, medications can be a very effective way of lowering blood sugars, reducing free fatty acids and controlling other risk factors during pregnancy.
Our advice is to do the best you can with diet and lifestyle based on your own needs and preferences. Small changes like reducing portion sizes of refined carbohydrates and including a good balance of vegetables, animal and/or plant-based protein with healthy fats can help a lot! You can also try small, short periods of targeted physical activity: Studies show that a simple 10-15 minute walk after a meal can substantially lower the after-meal blood sugar. This is important as the after meal period is when blood sugars are often at their highest. Therefore, walking for just 10 minutes after breakfast, lunch and dinner can be a manageable way of keeping your blood sugars as low as possible.
However, we recommend listening to the advice of your medical team and not being afraid to take medications if this is advised. And ask as many questions of your team as you need to. They are usually very happy to discuss the rationale for their recommendations! The right medical management can ensure both blood sugars and free fatty acids are kept low during pregnancy which will help keep you and your baby as healthy as possible.