A guide to starting insulin for women with gestational diabetes

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Starting insulin for women with Gestational Diabetes Mellitus (GDM)

How does insulin work?
Your body uses insulin to carry the glucose (sugars) in the food you have eaten around the body. People who do not have diabetes produce a constant level of insulin, and when they eat their bodies produce more in order to reduce the sugar levels in their blood to a normal level. In gestational diabetes, your hormones cause your body to become less able to use its insulin, causing the glucose to remain in your blood. This can give you high blood glucose levels which may affect your own and your baby’s health.

There are several types of insulin, but the two most commonly used in GDM are:

  • Novorapid™ – a very fast-acting insulin which is given immediately before a meal and works for a short period of time (3-5 hours).
  • Insulatard™ – a long-acting insulin which lasts for up to 24 hours.
  • Both insulins come in disposable injection pens.

The diabetes team will decide which kind of insulin you need, and when and how much you should inject. Once you have started taking insulin you need to keep testing your blood glucose as before, and to speak to the Diabetes Midwife or Nurse on a regular basis so that they can support you and advise you on changing your dose as necessary, depending on your blood glucose levels. If you are taking metformin you will be asked to continue with this as it reduces the amount of insulin you need.

Injecting your insulin


It is important that you take Novorapid™ 15 minutes before a meal unless you are advised otherwise. If you miss a meal for any reason, or do not include carbohydrates in your meal, you will not need to take your Novorapid™.


This needs to be given at bedtime. It is given in the same way as Novorapid™ but should be shaken first.

How to inject your insulin

  • Use a new needle every time
  • Dial up 2 units and discard (to check that the needle is working properly)
  • Dial up your required dose
  • Fully insert the needle at 90 degrees and press the plunger (the diabetes team will discuss and demonstrate where to inject)
  • Count 10 seconds before taking the needle out
  • Remove the needle from the pen and dispose of it in your yellow sharps bin

High blood glucose (Hyperglycaemia)

Ideally you should keep your glucose level below 5.3 mmol/l1 on waking and below 7.8 mmol/l one hour after eating a meal. If your readings are regularly higher than this (≥3 times in a week), please contact the Diabetes Midwife to discuss adjusting your dose of insulin. Remember that if your blood glucose is high, your baby’s will be too. Hyperglycaemia may be caused by not taking enough insulin, eating too many carbohydrates, being less active than usual, illness or infection, or simply due to pregnancy progression due to your pregnancy hormones.

Your insulin resistance increases throughout pregnancy, so you may need to keep increasing your insulin dose. If there is a chance that your baby may be born early, you may need a steroid injection to mature the baby’s lungs, and this can also cause your blood glucose to be higher than normal. If this is the case, you may need to be given extra insulin as an in-patient. The Doctors and Diabetes Midwife or Nurse will advise you on this.

Low blood glucose (Hypoglycaemia or ‘’Hypo’’)

Hypoglycaemia is a blood glucose level of 4.0 mmol/l1 or less) Early signs and symptoms of a hypo include:

  • Sweating heavily.
  • Feeling anxious.
  • Trembling and shaking.
  • Tingling of the lips.
  • Hunger.
  • Going pale.
  • Palpitations.

A number of situations can cause a hypo:

  • Too much insulin
  • Delayed or missed meals.
  • Eating less starchy foods than usual.
  • Unplanned or strenuous activity.

Sometimes there is no obvious cause, but treatment should always be carried out immediately, as advised. If you recognise that you are having a hypo, you should treat it immediately with something that will raise your blood glucose quickly (15-20g fast acting glucose). Suitable treatments are:

  • 150 mL (a small can) of non-diet fizzy drink, although amounts may vary,
  • OR 200 mL (a small carton) of smooth orange juice,
  • OR 4-5 dextrose tablets

If you do not feel better (or your blood glucose level is still less than 4 mmol/L after 10-15 minutes), repeat ONE of these treatments. You must go to A&E if your blood glucose levels are not improving.

Once your blood glucose has returned to normal, and if you are not due to eat a meal, eat a starchy snack, like a slice of toast or a small banana. You must let the Diabetes Midwives or doctors know if you are having hypos as these can be a medical emergency and they may need to adjust your insulin dose or look into other possible more serious causes.

Important  Information

If you are going on holiday, ensure that you have enough supplies with you, and ask your GP for a letter to verify that you need to carry needles/medical equipment through customs. Ensure that your travel insurance covers diabetes. It may also be advisable to inform your employer that you have started taking insulin.

Storing your insulin

Store the insulin you are not using in the door or drawers of the fridge (you should always keep a spare pen at all times in case one is faulty) The pen you are using can stay out of the fridge for one month at <28 degrees centigrade (it is useful to write on it the date you started it). If travelling, keep your spare insulin in a cooler bag or vacuum flask. NEVER store your insulin with a needle in place for safety reasons.


If you drive a car you must inform your insurance company that you have gestational diabetes and are taking insulin. If you are taking insulin for more than 3 months, you must inform the DVLA using a DIAB1 form (https://www.gov.uk/diabetes-driving). Failure to declare this may lead to a fine. You should always check your blood glucose no more than 2 hours before driving a car and every two hours while driving. If you are doing several short journeys you don’t need to test before each journey as long as you test every 2 hours.

You should ensure that your blood sugar is at least 5.0 mmol/l before driving. If you have a hypo while driving, it is important that you park the car, remove the keys and follow the instructions for hypoglycaemia given above. You should not start driving until 45 minutes after your blood glucose has returned to normal.

In labour

If your labour is being induced, you should continue to take your insulin as normal until labour starts. When you are in labour, the midwife will check your blood glucose hourly. If 2 or more of your readings are higher than 8.0 mmol/l, you may need to be given insulin through a drip.

Planned caesarean section

If you are having a planned caesarean section, you should take your insulin as normal the night before. On the morning of the operation you will be asked not to eat, so you will not need to take your medication.

After your baby is born

Once your baby is born you should stop all your diabetes treatments. As having GDM indicates a high risk of Type 2 diabetes in the future (50-80% in 5-10 years after birth), the following is recommended:

  • Fasting blood glucose 6-8 weeks after birth via your GP
  • Annual diabetes screening thereafter
  • You can also speak to your GP for a referral to the Diabetes Prevention Programme
  • Continue a healthy balanced diet and active lifestyle

Useful telephone numbers/websites