Management – GDM

Management – GDM

How to treat it?

There are four major initial aspects of treatment.

1. Diet and activity About two-thirds of people with gestational diabetes respond very well to watching their diet. Keeping track of your weight is helpful.  Older practice was a very restrictive diet, but now it is understood that the pancreas needs a reasonable amount of carbohydrates to work properly.  The modern diabetic meal plan is very close to a healthy normal diet.  It is important that your pancreas is not exposed to a large meal, so it is best to spread out your intake into 3 meals and 3 snacks.  Small amounts of food periodically throughout the day are much easier for your pancreas to process. As the baby consumes calories all night long, it is also important that you have a bedtime snack.

It is very important that you avoid really sweet things because these high-sugar foods tend to raise your blood sugar more and puts extra stress on your pancreas. Avoiding sugary pop and limiting the amount of juice you drink is important. Juice may be natural but it is high in fructose and glucose that will raise your blood sugar.  The less fat you eat the less likely you will be to gain further weight and aggravate the problem.  Fat is a much more concentrated form of energy than carbohydrates or protein.

Exercise and activity help to use up sugar.  Sometimes a 10-15 minute walk after meals will also lower the blood sugars.  Walking or gentle swimming are usually good exercise for pregnant women but check with your caregiver to be sure they are fine for you.

2. Monitoring Blood Sugar Once you are on the diet your physician or caregiver will need to know your blood sugar levels.  For this your clinic should provide you with a meter and ask you to check your blood sugar four times a day.  A nurse will usually check your sugar on your first clinic day by pricking your finger and getting a drop of blood. This is with the same type of machine that you will use.  It is important to know your blood sugar level before breakfast and one or two hours after each meal.  Everyone is different; consult your doctor or care giver for a schedule that suits your situation.  The timing of the test is usually from the start of the meal unless the meal is longer than 20 minutes, in which case use the mid point of the start and  end of the meal as the start of timing for the one or two hour interval (See Blog 21st Feb 2013). If your initial sugars are minimally elevated you may be able to get by with checking your sugar twice a day. As each week progresses, the amount of hormones coming from your placenta increases. Therefore, regular blood sugar monitoring up until the time of delivery is  important.

Your sugar should be within the following guidelines:

          Before breakfast                    below 5.3 mmol/l  (95 mgs/dl).  Those

                                                            centers that diagnose GDM at a fasting level of

                                                             5.1 mmol/l  (92 mgs/dl) use this target

          1 hour after meals                  below 7.8 mmol/l  (140 mgs/dl)

          2 hours after meals                below 6.7 mmol/l  (121 mgs/dl )

3. Confirming accuracy of the meter All your caregiver’s decisions will be based on the blood sugar readings from the meter.(See Blog 8th Jan 2016)  Therefore your meter readings must be accurate but the meters are not perfect (See GDM Research – 25th March, 2011).  Each meter varies a little from person to person and the guidelines for blood sugar control are quite strict.  Thus some clinics arrange for a check of your meter against the laboratory.  This will require a blood sample to be drawn from your arm.  The laboratory can then measure the blood sugar on the sample for an accurate reading of your blood sugar.  It is best if you do a blood sugar check on your own meter (using your finger) at the exact same time as the blood sample is drawn from your arm (within 5 minutes).  Write this result in your book and circle it so that it can be identified later and compared to the result from the laboratory.  Some clinics have three laboratory checks in order to make a good comparison. This practice allows you and your doctor or caregiver to know whether your meter is accurate.

4. Ketones Testing Both diet and blood sugar monitoring are very important, but it is also necessary to make sure your meal plan is not too strict.  Gestational diabetes can nearly always be controlled by a very restrictive diet but this may be harmful for the baby.  If your diet is too strict, the net result might be that you are not getting enough calories and in turn the baby is receiving less than what is ideal.  This is not good for your baby.

When your body senses starvation, it breaks down some of your body fat. This gets turned into ketones, which are passed out in your urine.  Your urine should be tested for ketones once a day at home. This should usually be done first thing in the morning.  You can purchase the ketone testing strips at any pharmacy and simply put the strip in the urine stream, tap off extra urine and then read the strip against the bottle.  If the urine ketones are negative, it means your diet is likely adequate.  Occasionally there is a trace positive and although this is not a major concern, if it is more than a trace amount, you will need to increase your bedtime snack. Speak with your physician or caregiver about your ketone levels if you have any questions about testing at home.  Once you have an established meal plan and the ketones are usually negative you may well be able to back off on the checking of ketones.

Follow-up If all the sugars are below the targets then continued adherence to the care plan from your clinic will usually hold the situation until the baby is born when the diabetes will typically go away.  Some centers feel if more than two values are raised then further treatment of the gestational diabetes is needed.

Many centers use the information as a teaching moment.  If eating a particular food type raises the blood sugar but otherwise all is perfect, then avoiding that food type may be all that is needed.  If the sugar is high when you sit around after the meal but it is okay if you move around, then it makes sense to keep more active after the meal.  If the glucose values are high and dietary indiscretions do not explain the problem then more needs to be done.  The options are insulin or tablets.

A. Insulin If the blood sugars cannot be controlled by diet alone, your doctor or care giver may start you on insulin. There are no tablet preparations of insulin because the acid in your stomach destroys it, insulin has to be given by injection.  Your care giver will teach you how to use the insulin and should have a guide sheet on how to adjust the insulin.  There is no exact dose of insulin that can be predicted to be needed, it varies from person to person and is guided by the response of the blood sugars.

If insulin is needed, it does not pass into the baby and is perfectly safe. If you do need insulin it is very important to continue checking your blood sugars four times a day so that you and your care giver know how well the insulin is working and that it is not causing any low blood sugar problems.

B. Tablets There are tablets (either glyburide or metformin) that can lower your blood sugar.  These are commonly used in Type 2 diabetes but more recently have been tried in gestational diabetes.  In a major study of using glyburide in gestational diabetes, 80% of the time it could control the blood sugars and the outcomes were similar to when insulin was used.   With metformin the sugar was controlled in 54% of women with gestational diabetes with good outcomes for the baby though babies were born a day earlier on average when on the metformin.  If your sugars are high throughout the day, these tablets can be an option.  Metformin is more often used as it has less chance of causing a low glucose level.  In most countries they are not formally approved for use in pregnancy but they are widely used.

Because the baby of a woman with diabetes can behave like a premature baby, special precautions are taken.  If at any time you notice the number of movements of the baby decreasing significantly, it may be a warning sign and you should call the obstetrician that day.  Most times a simple non-stress test will be performed on the labor floor, which only takes half an hour.  If the non-stress test is normal, it reassures you and your doctor that all is well.  If there is any concern, the baby can be watched more carefully.  Talk to your doctor straight away if you have any concerns.

Delivery On the day of delivery you continue with your diet until the obstetric team tells you to stop eating.  If you are on insulin you continue your insulin as long as you are eating.  Once active labour starts your sugars are usually checked every one or two hours if you have not been on insulin or just taking a lower dose (taking less than 1.0 units per kg of your weight).  Usually the blood sugar stays normal during labor because the muscle work of labor uses up any extra sugar.

If you have been on a large amount of insulin, your physician will usually need to give you insulin and sugar intravenously and adjust the insulin every hour depending on the blood sugar reading.


Post-partum After the birth of the baby, any insulin that was given during delivery is discontinued.  If insulin was needed during the pregnancy it is normally discontinued. The vast majority of women have normal blood sugars after the baby is born and can resume a normal diet.  If you plan on breast-feeding then there is no problem if you have had gestational diabetes; in fact, breast-feeding is encouraged as it frequently helps in weight control and is better for the baby.  You should check your sugar once on the day after the birth of the baby to make sure everything is back to normal.

Six weeks after the baby is born you will need another glucose tolerance test. It is a two-hour test with 75 g of glucose.  Talk to your doctor or care giver about arranging this appointment.

Long-term The important things in the long term are:

  • Weight control
  • Annual blood sugar checks/ Knowledge of the symptoms of diabetes
  • Advice for further pregnancies

Once you have developed gestational diabetes it means that your pancreas is not functioning perfectly and there is a higher risk for developing diabetes in the long term.  This risk is determined greatly by what happens to your weight.  If your weight is kept in the normal range, the risk is as low as 10% but if you do gain weight it may be as high as 50-60%.

You should have a blood sugar check once a year with your general practitioner.  If you develop thirst, go to the bathroom to urinate a lot, or get frequent vaginal yeast infections, have your sugar checked, as these may be symptoms of diabetes.

If you wish to get pregnant again, you should have a blood sugar check before getting pregnant, as there are serious risks to the baby if the sugar is high at and just after conception.

Gestational diabetes can be overwhelming in addition to the many other preparations and obligations you have during pregnancy.  However, once it is diagnosed and the treatment is started, it is usually easily controlled.  With blood sugar control, the chance of a healthy baby is about the same as if you didn’t have diabetes at all.

If you have any questions, write them down and bring the list with you on your next visit to the doctor.