For many women diet and physical activity are enough to keep blood glucose levels in the healthy range for pregnancy, however for some, additional treatment options need to be considered. This leaflet provides you with information about treatment options.
Sometimes blood glucose levels remain elevated even if you are following the diet and being physically active. This means your body is not able to produce enough insulin to cope with the extra demands of pregnancy.
It is very important that you do not over-restrict your food to keep your blood glucose levels down, and that you eat to appetite. Restricting the diet too much is not the answer as this can lead to weight loss (which may not be desirable). It is better to add on medication so that you can eat the balanced diet you need to support a healthy pregnancy and prepare for breastfeeding.
Understandably women are cautious about taking medication during pregnancy, but it is better for your baby’s wellbeing to be exposed to blood glucose levels in the healthy range for pregnancy, even if this can only be achieved with the support of medication.
There are very few medications to lower blood glucose levels suitable for use in pregnancy; they include Metformin and Insulin, alone or in combination.
When the blood glucose levels are rising above target levels your own insulin production can be ‘topped up’ with an injection of insulin to keep blood glucose levels within the normal range.
Needing to do an injection may sound a bit daunting but the injection is simple. It is given with a short needle into the fatty tissue just under the skin and is much less painful than the finger pricks you are already doing. We have a demonstration video for you to watch on the Rosie website which will help this to become clear for you.
The insulin that you take does not cross the placenta to your baby.
There are two times for giving insulin
- If the blood glucose levels are above target on waking you will be asked to give an injection of slow release insulin also known as background insulin which you will take before bed, about the same time each night. Types of background insulin include – Insulatard, Humulin I and Levemir.
- If the blood glucose levels are above target after eating meals you will be asked to give an injection of quick acting insulin just before eating the meal. This may be at one, two or all of your meals. Also described as bolus or rapid acting insulin. Types of quick acting insulin include – Novorapid and Humalog.
We will support you to learn how to balance the insulin dose with the food that you eat and your activity levels, to keep your blood glucose levels in the normal range.
The dose of insulin is likely to increase as your pregnancy progresses, this is normal. Daily blood glucose monitoring is very important as it shows when a change in insulin dose is needed.
Insulin can cause low blood glucose / sugars (hypoglycaemia). However this is unlikely to happen for most women since you will be on small amounts of top-up insulin. We will discuss any individual risks with you.
It is important to keep your blood glucose levels in the healthy range for pregnancy, right up to the point of birth. This means that during labour you will continue to give your usual doses of insulin and remain on the diet until your baby is born.
If blood glucose levels rise above 8.0mmol/l during labour, your care team may advise to change to an infusion of insulin through a drip, for the remainder of the labour.
Once your baby is born you can stop taking the insulin and return to a normal healthy diet but we ask you to continue to check your blood glucose levels for 24 hours.
Metformin is a tablet that has been given approval for use in pregnancy by NICE (National Institute for Clinical Excellence) and more recently by the Medicines and Healthcare Products Regulatory Agency and the Commission on Human Medicines. It is known that Metformin crosses the placenta but research has shown no safety concerns around the use of Metformin in pregnancy. Metformin can be use alone or to supplement the use of injected insulin during pregnancy if clinically indicated.
Metformin works by enabling you own insulin to work more effectively, so a smaller amount of insulin will work better. This can mean that the addition of Metformin to your dietary changes and increased activity will be enough to keep your glucose levels in the healthy range for pregnancy.
Metformin can be useful as an addition to insulin injections. Using them together can keep injected insulin doses lower. This can help prevent excessive pregnancy weight gain and therefore improve pregnancy outcomes.
Metformin is not always the best choice for everyone. There are medical conditions or pregnancy complications that may mean insulin would be a better choice. Your pregnancy team will discuss this with you.
Metformin can sometimes cause transient (short lived) gastric (stomach) upset. This side effect can be minimised by starting on a low dose, and building up the dose slowly every 3-4 days, if required, and by taking the tablet with or immediately after food. The effect of Metformin on your blood glucose level is not as immediate as insulin and may take a few days to see the full effect
It is important to keep your blood glucose levels within the healthy range for pregnancy , right up to the point of birth. This means that during labour, you will continue to take your usual doses of Metformin and remain on the gestational diabetes diet until your baby is born. If your blood glucose levels rise above 8.0mmol/l during labour, your care team may advise that you change to an infusion of insulin through a drip, for the remainder of your labour.
Once your baby is born you should stop taking the Metformin (unless you have been advised otherwise by the pregnancy team) and return to a normal healthy diet but we ask you to continue to check your blood glucose levels for 24 hours.
Starter doses for metformin
On days 1, 2 and 3 – please take one tablet with breakfast or evening meal (you will have been advised which meal to start taking the Metformin with).
On days 4, 5 and 6 – if you have been tolerating one tablet with one meal then please start taking it with the other meal. So take one tablet with breakfast and one tablet with evening meal.
On days 7, 8 and 9 – if you have been tolerating one tablet with breakfast and with evening meal then please start taking a second tablet with the meal that you first started taking the Metformin with and continue with one tablet at the other meal.
On day 10 and onwards – if you have tolerated two tablets at one meal and one tablet at the other meal then please start taking two tablets at both breakfast and evening meal and continue with these doses.
If however, you have any side effects after a dose increase please go back to the previous dose tolerated and continue this for a further three days before attempting to increase the dose again.
On days 1, 2 and 3 – please take one tablet with breakfast or lunch or evening meal (you will have been advised which meal to start taking the Metformin with).
On day 4 and onwards – if you tolerated the one tablet with the one meal then please increase to two Metformin tablets with that meal and continue with this dose.
If however, you have any side effects after taking two Metformin tablets please reduce back to one tablet as tolerated and continue this for a further three days before attempting to increase the dose again.
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Cambridge University Hospitals
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