The most important part of treating GDM is to eat the right amount of healthy food and be active. The diabetes team will discuss with you the best way of doing this. It is also important to see how treatment is affecting your blood sugar levels, so keep testing each morning before you eat and after each meal. Again, the diabetes team will explain what glucose levels they want you to aim for and the timing of your tests. If your sugar tests remain elevated, this tells us that too much sugar is going to your baby. Like anyone who is fed too much sugar, the baby may become unhealthy and it may also become fat. Sometimes, the high sugar affects the blood flow through the placenta and the baby can become too small instead of too big or it can be associated with high blood pressure complications for you. So, what can we do to try to keep your pregnancy as normal as possible?
Firstly, it is very important that you DO NOT starve yourself to try and reduce your sugar levels further. The baby needs a balanced diet and if you restrict your carbohydrates (the name for sugars that are all bound together in foods such as bread, rice and pasta) too much, your body will not function normally. Ketones build up in the blood and this may not be good for the baby.
It is important to achieve a healthy level of sugar in your blood for your baby. If you are unable to do this with a healthy diet and staying active, insulin or metformin (or both) can help you reach your target. Talk with your diabetes team to help you make the best decision for you and your baby.
So, what do we recommend?
One option is to take insulin
Your sugar level is elevated because the insulin your own body makes is not working efficiently and your body cannot make enough extra insulin to keep your sugar level down. However, if you take extra insulin by a simple injection just under the skin in your tummy, the sugar level will come down. Some women only need background insulin that works overnight to bring the sugar level down in the morning. Some women need mealtime insulin to stop the sugar level increasing too much after a meal. Many women need both types of insulin and may require 4 injections a day. Most women are anxious about the idea of insulin, but they are surprised how easy it is to give and the injection is much less sore than the finger-prick tests.
Insulin goes into your body to reduce the sugar level, but does not cross to the baby. If the dose of insulin is right for you (and everyone needs a different amount) the sugar level in your blood will improve and this means that a healthier amount is going to the baby.
It is important that insulin is balanced with your food and activity. If the balance is not correct the sugar in your blood will remain too high, or drop low. If it drops low, your body will have symptoms of “hypoglycaemia”. The diabetes team will teach you how to recognise and treat this.
If you need insulin, we stop the treatment when you are in labour or when you stop eating prior to a caesarean section. Your body does not become dependent on insulin.
Another option is to take metformin
Metformin is a tablet that helps your own insulin do its job better, so that you are able to keep the sugar level down more easily. One advantage of metformin compared with insulin is that metformin does not make the sugar drop too low (does not cause hypoglycaemia).
Metformin crosses to the baby, so careful studies have been performed to show that metformin is safe during pregnancy and the outcomes for the baby are good. Children whose mothers have been treated with metformin during pregnancy have been followed until 8-9 years of age and their growth and development has been similar to children whose mothers were treated with insulin. Your doctor can explain more details about these studies if you have questions.
Metformin is not an option for everyone and you would need to check with your doctor whether it would be a good choice for you. There are certain medical conditions or pregnancy complications that mean insulin would be a better choice. Also, some women (two out of every ten) experience side-effects, typically diarrhoea, when they first start metformin. This usually settles within a few days of starting treatment and most women are able to continue taking it. We try to reduce side-effects by starting with a low dose and increasing it (up to a dose of 2,500mg/day) until the sugar levels are in range. This usually takes 1-2 weeks. Metformin should be taken with food in the stomach so we recommend it is taken during or immediately after eating.
Metformin is not as strong as insulin, so a number of women treated with metformin also require insulin as well. As women who take metformin generally gain less weight than women who take just insulin, a combination of metformin and insulin may be a good option rather than just changing to insulin. Also, if your doctor recommends that you also start insulin, you may only need 1 or 2 injections a day instead of 4 injections a day.
Pregnancy Diabetes Care, © 2016