GDM is a form of diabetes, but specifically only related to pregnant women, and almost always reverts once your baby is born. The cause in pregnancy is due to the naturally occurring pregnancy hormones that block the insulins action (insulin is the hormone we produce to decrease our blood sugar levels), this therefore causes insulin resistance. In pregnancy our requirements for insulin production increase throughout, however not all women’s bodies can cope with this and therefore we see our BSL’s (blood sugar levels) increase.
People at increased risk of becoming a gestational diabetic are:
- Increased maternal age
- Immediate family or previous (self) history of GDM or type 2 diabetes
- Increased BMI
- Some autoimmune diseases, medications & PCOS
- Sleep deprivation
How does GDM get diagnosed?
In any pregnancy, many tests, treatments & procedures are offered, recommended and done. The test for gestational diabetes, (Glucose tolerance test or GTT) is one of these and usually offered between 24-28 weeks gestation.
The test is conducted at a pathology lab, where you will need to be fasting (no food or drink other than water from the night before). A blood test is done to check your fasting BSL then a sugary bubbly drink containing 75g glucose needs to be drunk within 5 minutes (it’s kinda the pits given you have an empty tummy and it is around 8.30am!), before two further blood tests are taken one and two hours post drink. Take your book/phone etc. to keep you occupied for the hours you will be at the clinic for!
The parameters for your health care provider to diagnose GDM have just changed slightly over the past few years. If any of the three blood test results come back outside the normal ranges in the table below you will be diagnosed with GDM.
Fasting (blood test one) - Greater than or equal to 5.1mmol/L
One hr post drink (blood test two) - Greater than or equal to 10.0mmol/L
Two hrs post drink (blood test three) - Greater than or equal to 8.5mmol/L
Why does your health care provider offer this test in pregnancy?
Gestational diabetic testing has become a standard amongst main stream obstetric practice. The main reason the testing is offered and implemented is to decrease the risks associated with uncontrolled/undiagnosed gestational diabetes. We know that well controlled diabetes has few complications compared to a non gestational diabetic, but when a woman’s blood sugar levels are uncontrolled this can lead to complications for both mother and baby in utero and post birth. The most significant one being the complications that arise with having a larger than your pelvis can might be able to handle baby.
Like anything in pregnancy, it’s important to understand why you are undergoing these tests, if they are necessary for you, & what is the outcome going to bring? Make sure you chat with your health care provider regarding this test and any others you are offered.
Some tips that I have found useful when having my GTT are:
Don’t, I repeat DO NOT take a toddler with you for the 2+ hours you will be at the pathology lab. I learnt the hard way and don’t want any others to suffer!
Try to remain as stress free as possible, especially in the lead up to the big day (stress increases BSL’s). Try a meditation (lots of apps available on your phone-or come to Calmbirth & you get some from us too!).
Do try and eat well in the couple of days prior to the test, include some carbs in your nighttime meal, but try to reduce the amount of refined sugar you are having (also, just try to eat well in pregnancy regardless of GDM testing!)
Drink lots and lots of water. This helps you be well hydrated and therefore less likely to feel faint etc. whilst being fasted. It also helps the pathology people to get your blood easier- win win!
Take a book, laptop for work or something to do while you are waiting for your tests - you’re not meant to move about much so sitting in the waiting room for hours can get a bit boring.
Have a plan in place for where you are going to go and get coffee/lunch/brunch post the whole process! You deserve it!
For more information and for references of this information, check out these resources: