Low levels with gestational diabetes – How low is too low?

Many mothers diagnosed with gestational diabetes are not given much information or advice about low levels. A question that we get asked frequently in our Facebook support group, is “how low is too low?”

how low is too low?

Levels below 2.0mmol/L should be reported to a health care professional, but if they are just lower than what you consider normal then please continue reading.

The answer to this question differs depending on how your gestational diabetes is controlled:

If you take Insulin or Glibenclamide:-

If you are taking Glibenclamide or Insulin to help control your blood sugar levels (at any point in the day) then levels below 4.0mmol/L are classed as ‘too low’, a good phrase to remember is “four is the floor”

As Glibenclamide is a sulfonylureas medicine it can cause hypoglycaemia (or hypos), the same as insulin.

Please note: some medical teams may advise that a hypo is a blood sugar level below 3.5mmol/L rather than 4.0mmol/L.

To learn more about hypos and how to treat them, please read more here.

If you do not take any medication OR if you use Metformin:-

If you are controlling your blood sugar levels with dietary changes alone OR with Metformin then you cannot have a true ‘life threatening’ hypo and lower levels should not be a cause of concern.  

You may experience lower levels (e.g. levels below 4.0mmol/L) and have ‘hypo type symptoms’, which can be unpleasant, but there is no need to treat the hypo symptoms with glucose to raise levels. In fact, this can worsen the problem.

Eating a normal, gestational diabetes-suitable snack will raise levels enough and should make you feel better.

This is known as a ‘false hypo’. More information on false hypos can be found on our false hypo page.

how to treat a hypo

Levels below the lower test target

Mothers often get concerned when their levels are below or towards the lower end of their test target range. But this is not a cause of concern unless levels are extremely low i.e. if your target level is to be 5.3mmol/L for your morning fasting level and get levels in the range of 4.0 – 5.2mmol/L this is fine, it’s actually a good thing!

Symptoms of low blood sugar levels

Some people may experience symptoms when blood sugar levels drop.

The sugar detox

Hypo-type symptoms are often experienced following the diagnosis of gestational diabetes, where the body has been used to running at much higher blood sugar levels for some time.ย 

Following the diagnosis and after making dietary changes by cutting sugars and reducing carbs, the body notices the drop in blood sugar levels, panics and sends out stress signals as it thinks levels have dropped too low, however on testing, levels are within normal parameters. This is known as a false hypo.

Levels dropping after eating

Another commonly asked question in our Facebook support group is why have my levels dropped after eating?

99% of the time when we ask what that person has eaten, the answer will be that they have eaten a meal with very little carbohydrates.

Meals that are made up of high protein and very few carbs will very often result in levels lower than the pre-meal test and an example of this recently was a meal of chicken breast and salad.

Whilst you may think hooray! …a great way to get lower levels, beware. Small amounts of starchy unrefined carbohydrates should be eaten at every meal to give energy and prevent high levels of ketosis. To learn more about ketosis and ketones with gestational diabetes, please see more information here.

If you see low levels after eating, then the next time you eat this meal, increase the amount of starchy complex carbs slightly.

meals which contain very little carbs alongside high protein can often cause lower post-meal levels

Low levels and placenta problems

As our insulin resistance is caused by hormones from the placenta, lower blood sugar levels can sometimes be a sign that there are problems with the function of the placenta.

To learn what things to watch out for and to find out further information on placenta issues with gestational diabetes, please read more here.

Do low levels impact the baby?

Having hypos or low blood sugar levels does not impact the baby unless you were to physically hurt yourself by fainting and falling down, or fitting (which is rare with gestational diabetes).

The baby will take what it needs from you. High blood sugar levels are, however, a concern for baby. For more detail on the complications high blood sugar levels can cause, please read more here.

Any concerns, call a medical professional

If you have any concerns over low levels of gestational diabetes then always seek advice from a medical professional.

If you experience any changes in the baby’s movements as a result of low levels then you should always call your maternity assessment unit for advice.

For more information on your baby’s movements, please see Kicks Count website.