The number of women diagnosed with Gestational Diabetes (GD) in Australia has steadily increased since the introduction of universal screening in 2015 and then again in 2017 when the threshold for diagnosis was lowered. So what is the problem with routine testing for Gestational Diabetes? Is there even a problem, or am I barking up the wrong tree? Let’s have a deep dive!
First, the GD low down!
So what is Gestational Diabetes? Basically, when in a non-pregnant state, our body digests carbs and turns them into glucose. The pancreas then releases a hormone, insulin, which moves the glucose from the bloodstream to the body’s cells, where it is used as energy to make the body’s cells work properly.
When pregnant, the placenta produces hormones (estrogen, cortisol, and human placental lactogen) that help the baby grow by reducing the insulin response, which, in turn, keeps more glucose in the mother’s bloodstream to be transferred to the baby. This is called Insulin Resistance (IR) and can increase a pregnant woman’s need for insulin three-fold. With more insulin being produced, more glucose is also produced, increasing blood glucose levels (BGL) after eating, giving baby access to more nutrients.
This is a normal function of pregnancy. However, as the placenta grows, it produces more of the hormones that reduce insulin response, and the risk of insulin resistance increases. Normally, the mother’s pancreas can make additional insulin to overcome IR, but when insulin production is not enough to overcome the placental hormones, GD results in between 5 and 10% of women around the 24th to 28th week of pregnancy.
Phew…I hope you got all that. It’s complicated salad of big words!
If IR is basically a normal function of pregnancy, why all the fuss?
Because babies of mothers with gestational diabetes are vulnerable to several chemical imbalances, like low serum calcium and low serum magnesium levels, and jaundice, but, in general, there are two major problems associated with gestational diabetes:
- Macrosomia – When mum’s blood carries too much glucose, baby’s pancreas senses the high glucose levels and produces more insulin. The combination of high blood glucose levels from mum and high insulin levels from bub can result in large fat deposits in baby, which causes them to grow excessively large.
- Hypoglycemia – Immediately after birth, if baby leaves a high BGL environment (if mum’s BGLs have been consistently high) and they still produce high insulin levels but no longer have high levels of sugar coming from mum, their own BGL will drop very quickly, resulting in hypoglycemia, which can lead to coma and death if not treated.
So, what are the risk factors for GD?
Although the cause of GD is unknown, and any pregnant person can develop GD during pregnancy, some common risk factors have been identified and are universally used. They are:
- Age – 25+ years
- Family history of type 2 diabetes
- History of GD in previous pregnancies, PCOS or macrosomic (large) babies
- Pre-pregnancy weight – overweight or obese
- Ethnicity – BAME, Indigenous Australian, Pacific Islander, Maori, Middle Eastern, Hispanic, Latino, American Indian
OK, but what is routine GD Screening?
In Australia, pregnant people are offered* a routine GD screening test around weeks 24 to 28 of pregnancy. It is called an ‘oral glucose tolerance test’ (OGTT), and you will be asked to:
- Fast for 10 hours (generally overnight, missing breakfast)
- Have a blood test
- Drink a 75g glucose drink
- Have another blood test at 1 hour
- Have another blood test 2 hours later.
- You must remain at the laboratory or doctor’s office for the full 2-hours
Women who have BGLs above 8-9mmol/L (140-160mgdl) two hours after having the OGTT drink are considered above the normal range and are diagnosed with GD. Because the threshold for diagnosis was lowered in 2017 and the OGTT is quite a sensitive test, it results in much higher diagnosis rates than other tests, but it is not without its controversies.
Is the OGTT accurate?
Now, even though the OGTT is currently the gold standard reference test for GD screening, it is notoriously inaccurate for GD diagnosis and offers no real outcomes in predicting fetal macrosomia or shoulder dystocia, which are the two main risks that are used as a reason screening for GD.**
The OGTT also has low reliability meaning that pre-test factors, including length of fast time, physical activity before testing, gastric emptying speed, stress levels at time of test and sleep levels leading up to testing, can all affect the results. In addition to this issue, there is also the issue of low reliability and reproducibility, meaning that if the test were repeated two weeks later, the same result might not be achieved. For example, at week 28, you could test positive when you tested negative two weeks earlier because pregnancy increases a woman’s insulin resistance over time. So basically, it is also time-sensitive, but it is impossible to know when the ‘right’ time is for each individual pregnant person.
There is also evidence to suggest that the OGTT may overestimate the prevalence of GD by as much as 16%.***
What are the side effects of OGTT?
Anyone who has done the OGTT screening test will have a tale about how uncomfortable the whole procedure was. Not only do you need to fast and be available at the testing site for 2+ hours, but you also need to drink the sickeningly sweet drink and have blood drawn. Not exactly a day at the park, in my opinion!
However, serious side effects from this test are very uncommon. Some people feel nauseated, sweaty, lightheaded, or may even feel short of breath or faint after drinking that much glucose, but that is usually it for physical side effects.
I’m going to be controversial here and suggest that the biggest side effects of the OGTT Screening are the long list of interventions women are subjected to once they have a GD diagnosis.
Now if you just felt your head spin…please bear with me while I explain.
Once a person is diagnosed with GD, their pregnancy journey suddenly takes a whole different route. They no longer fit into the pregnant person box. They are now shoved in the HIGH-RISK pregnancy box, and this is a whole different kettle of fish.
Now they need to be seen by the ‘diabetes educators’ who set them up with a blood glucose monitoring routine where they need to test their BGL levels first thing in the morning and then again two hours after the start of their main meal. Blood glucose monitoring indicates the amount of glucose in the bloodstream at that exact point in time. The levels are recorded and reported to the health care team to decide if changes are needed – changes to carbohydrate intake, more regular exercise, practising stress management techniques or commencing medication or insulin. Of course, to decide if changes need to be made to any of these things, strict food and activity diaries are also put in place, and women are made to feel guilty about everything they eat if their BGL moves out of the approved range.
Often diabetes educators are so under the pump because of all of the women who receive GD diagnoses through universal screening (including those with false positives) they are barely able to give the most rudimentary support to their patients. Very rarely are care plans properly modified to the woman’s personal requirements, like taking cultural eating and food habits into account. Or telling women with long-standing and complex health and exercise routines that they ‘need to start walking’ to bring their BGLs under control.
Once all of this is in practice, and the pregnancy is now even more highly monitored, the threat of interventions is also ramped up. Suddenly the medical team start planning an early induction (37-38 weeks) to avoid shoulder dystocia or macrosomia like it is a foregone conclusion. And if the woman has the audacity to push back and decline the induction, the ‘dead baby card’ is played with impunity.
If the woman agrees to the induction, she is subjected to the circus of trying to get an unreceptive body to accept labour. This often leads to long, complex inductions, which end in the full cascade of interventions because labour has been forced before the baby or woman is ready for birth.
All of this adds to the stress the woman is under, causing changes in blood glucose levels and impacting their overall mental health. It is a vicious circle with wide-reaching consequences. And in my humble opinion, these are the REAL side effects of a GD diagnosis.
Are there risks if I refuse the routine testing for Gestational Diabetes?
If you listen to the majority of the information that is handed out by hospitals or easily accessible online, you will read a long laundry list of all of the risk factors of undiagnosed GD, so I’m not going to regurgitate them here.
What I will do, however, is direct you to the brilliant French OB, Michel Odent, who has a great blog, “Gestational Diabetes: A Diagnosis Still Looking For a Disease?” where he breaks down GD through a whole new and eye-opening lens. Once you have read his blog, you may like to go back and look at the info from your OB again before making your own mind up.
So, what IS the problem with routine GD screening?
Obviously, this is my own personal opinion, and I am open to discussion and gentle debate, but I believe routine screening for GD is like squashing a bug with a sledgehammer.
Gestational diabetes has long been a controversial topic, and I suspect it will continue to be for quite a while, but the issue, according to Dr C.K. Hegarty, is that “despite the increasing numbers of women diagnosed, there is little to suggest outcomes are improved.” So basically, all of the stress women endure after their diagnosis is all for naught because the constant monitoring, inductions and other interventions don’t improve outcomes.
Babies are born big, and shoulders occasionally get stuck…if OBs and midwives were trained in supporting women to birth rather than pathologising birth, they would be able to manage these variations of normal without needing to rush to surgery or instrumental birth.
Borrowing from Dr Odent again, who describes GD as a ‘diagnosis looking for a disease’…
Gestational diabetes is a typical example of a term with a strong nocebo effect. It has the power to transform a happy pregnant woman into an anxious or depressed one … One of the side effects of the term ‘gestational diabetes’ is to transform the interpretation of the results of a test into a disease. The status of disease implies that complications have been identified. It is commonplace to claim that macrosomia (a big baby) is the main complication. This should be considered an association. It is obvious that the energy requirements of a big baby are not the same as the requirements of a small one: the mother, who must make a bigger effort than others, is labelled as having ‘gestational diabetes’ … The nocebo effect of the term ‘gestational diabetes’ is becoming a serious issue. The use of enlarged criteria to interpret the tests is one of the reasons why the number of women diagnosed with gestational diabetes is increasing” (Odent 2013: 100-02).
Yes, there will be some women who develop GD, and if left undiagnosed and untreated, they may endure complications in their pregnancy and labour, but the way routine screening stands now, women are unnecessarily being pathologised and misdiagnosed without improved outcomes from the ‘treatment’ they receive. The fact is, rather than improving outcomes, the diagnosis tips otherwise healthy pregnant people into ‘high risk’ categories that cause significant stress, trauma and injury to her and her baby.
In my opinion, there are many problems with routine testing for Gestational Diabetes, and they all come down to the medical-industrial complex that places profit, quick turn over and policy ahead of patient well-being. The medical system must sort its sh*t out and develop better criteria than the lazy routine screening it uses now. All it is doing is herding unsuspecting women towards unnecessary interventions and complications while trying to control a birth outcome that wouldn’t be problematic if OBs and midwives weren’t being deskilled by working in a system that puts profits ahead of women and their well-being.
Follow me on Instagram for a slightly controversial but always truthful take on Industrial Birth BS, ‘Good Girl‘ conditioning and birth preparation – @graceandivybirthandwellness
*Notice how I said you will be OFFERED a routine GD screening test…that’s because it’s not compulsory. You can choose whether you want to take the screening or not. Be aware that if you choose not to take the test, you will be hounded by your medical team, but just know that the choice is yours to make as long as you are comfortable with the level of radical responsibility required to go against your doctor’s advice. Your Human Rights in healthcare and childbirth come before any hospital policy or medical advice.
**Pintaudi B, Di Vieste G, D’Anna R, Chiereghin F, Biamonte E, Corrado F, Di Benedetto A. The Analytical Reliability of the Oral Glucose Tolerance Test for the Diagnosis of Gestational Diabetes: An Observational, Retrospective Study in a Caucasian Population. J Clin Med. 2022 Jan 23;11(3):564. doi: 10.3390/jcm11030564. PMID: 35160016; PMCID: PMC8837109.
***Oral Glucose Tolerance Test (OGTT): Undeniably the First Choice Investigation of Dysglycaemia, Reproducibility can be Improved (https://www.intechopen.com/chapters/76474)
