Gestational Diabetes: beyond the label

Updated: August 2019

I have written this blog post in response to readers’ requests. Trying to make sense of the research and guidelines hurt my brain, and I almost gave up a few times. So, for those who asked – I hope this post meets your expectations! The post explores blood glucose levels (BGLs) in pregnancy, and attempts to make some sense of the fairly nonsense diagnosis and management of ‘gestational diabetes’ (GD). This post is not about Type 1 or Type 2 diabetes, and I am assuming you already know about the relationship between blood glucose (sugar) and insulin – if not do some googling.

Blood glucose and insulin in a healthy pregnancy

Babies needs glucose to grow, and the demand for glucose increases as pregnancy progresses and the baby develops. From around 20 weeks, placental hormones cause insulin resistance in the mother’s cells. Insulin resistant cells are less able to convert glucose into energy, resulting in a peak of blood glucose after eating a meal which goes through the placenta to ‘feed’ the baby. In response to this peak, the woman’s pancreas increases the production of insulin to bring BGLs back down to a healthy pre-meal range. So, during pregnancy the woman’s body needs to bump up insulin production to counteract the effect of insulin resistant cells. Once the baby is born, the placental hormones stop entering the woman’s circulation and her insulin metabolism returns to her pre-pregnant state.

High blood glucose in pregnancy

[NOTE: the clear as mud definition of ‘high’ is discussed below in ‘parameters of normal’]

Some women’s bodies are unable to produce the additional insulin required during pregnancy. This results in high levels of glucose remaining in the blood instead of being converted into energy by insulin. The exact cause of this situation is not clear. However, pregnancy places additional demands on the body’s metabolism, and pre-existing health issues influence the ability of the body to meet these demands. High BGLs in pregnancy are associated with an increased chance of health problems during pregnancy (eg. pre-eclampsia) and later in life (eg. cardiovascular disease and Type 2 diabetes). Therefore, pregnancy may offer a glimpse into the general health of a woman, and her ability to meet physical challenges. Rather than causing ill health, abnormal BGLs may reflect underlying ill health.

What is known is that high maternal BGLs influence the development of the baby. In early pregnancy (before 14 weeks) high BGLs are associated with an increased chance of miscarriage, congenital abnormality and subsequent stillbirth (Murphy et al. 2017). This is because the structural development of the major organs is taking place at this time, and any toxin, including excessive glucose can cause damage. However, BGLs are only high in early pregnancy in poorly controlled, pre-existing diabetes.

bayi-tidur-gemuk-tangan

In contrast, ‘pregnancy induced’ high BGLs do not occur until after 20 weeks when insulin resistance kicks in. By 20 weeks all of the baby’s major organs have formed, and the baby grows mostly in size rather than in complexity. Therefore, pregnancy induced high BGLs primarily effect the weight/shape of the baby. In response to maternal high BGLs passing through the placenta, the baby increases their own insulin production. This insulin converts the excess blood glucose into additional fat stores resulting in a heavier baby. This extra fat is concentrated around the baby’s upper body, in particular around the shoulders. Chunky shoulders increase the chance of shoulder dystocia and perineal tearing during birth. Insulin can also delay the production of surfactant, which prepares the lungs for breathing. This can cause breathing issues at birth, particularly if the baby is born early (eg. by early induction or c-section – which are more common when GD is diagnosed).

Once the baby is born, they no longer need to produce high insulin. However, adjusting and re-balancing insulin and BGLs can be a bit of a bumpy ride for the baby. The withdrawal of high BGLs is sudden (as soon as the placenta stops functioning); but it can take some hours before the baby’s insulin levels drop. During this time the high insulin can covert too much of the baby’s blood glucose into energy resulting in low BGLs (hypoglycaemia).

The baby’s high insulin levels during pregnancy also increase their red blood cells. After birth the baby needs to break down and excrete these additional red blood cells. A by-product of breaking down red blood cells is bilirubin. If there is a lag between breaking down the red blood cells and excreting them out of the body, bilirubin builds up causing jaundice. Jaundice is common in babies who produced high insulin in the uterus.

The effects of high BGLs and high insulin in utero may also cause long term epigenetic changes to the baby’s metabolism. These babies have an increased chance of developing obesity and Type 2 diabetes later in life.

If you want a more in-depth explanation watch this movie:

In summary high BGLs in pregnancy are not ideal, and can alter the growth and development of the baby.

‘Gestational Diabetes’

In an attempt to identify and manage women with high BGLs, the maternity system has defined a disease and created a label that clinical guidelines can be based around. When high BGLs are identified for the first time during a pregnancy it is referred to as ‘gestational diabetes’ (GD) or ‘gestational diabetes mellitus’ (GDM). Most cases of GD are pregnancy induced ie. caused by an inability to meet the additional insulin needs of pregnancy – as described above. Occasionally, Type 2 diabetes was already present but only identified in pregnancy. Either way – high BGLs will be termed GD until proven otherwise ie. after pregnancy when BGLs fail to return to normal in the case of undiagnosed Type 2.

However, due to inconsistencies in who is tested, and how and what parameters are applied, there is a huge variation in whether an individual woman gets diagnosed and labelled with GD or not. For example, the incidence of GD varies globally from 2% to 26% depending on the definition used, the approach to screening, and the population of women tested.

Applying the label

label-removal

There are two main approaches to screening for GD – universal screening (every woman is offered a test) and risk factor-based (only women with an increased chance of developing GD are offered a test). There is no evidence to demonstrate that either approach improves outcomes for mothers and babies. A Cochrane Review concluded: “There is not enough evidence to guide us on effects of screening for GDM based on different risk profiles or settings on outcomes for women and their babies… Low-quality evidence suggests universal screening compared with risk factor-based screening leads to more women being diagnosed with GDM.”

TYPES OF TESTING

The Oral Glucose Tolerance Test (OGTT) is offered between 24 and 28 weeks gestation, or earlier for women considered ‘at risk’ of GD. It is the standard recommended test for GD diagnosis in most clinical guidelines worldwide. It involves fasting overnight, then drinking a glucose solution, followed by a blood test to assess BGLs. The dose of glucose can vary from 50g, 75g to 100g; and the timing of the blood test varies from 1 hour, 2 hours or 3 hours afterwards. There is no evidence to support any of these variations, however most guidelines recommend 75g of glucose and a 2 hour blood test. The OGTT assesses how well a woman’s body responds to a huge bolus of glucose (and chemicals – read the label).

The Glucose Challenge Test (GCT) was previously recommended as a screening assessment (24-28 weeks) to determine which women went on the have the OGTT. The test involves drinking a 50g glucose solution and having a blood test 1 hour later. However, the test lacks both sensitivity and specificity and is no longer recommended (except in the US).

The Glycated haemoglobin (HbA1c) is only recommended for identifying pre-existing diabetes during the first trimester of pregnancy. The results of the blood test provide an indication of what the average BGLs have been over a 2-3 month period. This test cannot effectively identify pregnancy induced diabetes – only previously undiagnosed Type 2 diabetes.

Self testing is not recommended in any guidelines – however some women choose to do this rather than an OGTT. The woman tests her own BGLs over a few days to get an idea about what her BGLs are doing when she is following her usual diet and lifestyle.

PARAMETERS OF NORMAL

It is generally agreed that the normal range of blood glucose for non-pregnant people is 4.0 to 6.0 mmol/L (millimoles per litre) when fasting, and up to 7.8 mmol/L two hours after eating. Diagnosis of non-pregnant diabetes occurs when an OGTT identifies fasting BGLs  ≥ 7 mmol/L or BGLs ≥ 11.1 two hours after 75g glucose.

However, when it comes to pregnancy, definitions and parameters of normal are not so clear. Various organisations advocate differing diagnostic parameters, and Bonventura, Ernest & Dee (2015) describe a number of them. However, I’ll stick to the most commonly used criteria initiated by the International Association of Diabetes and Pregnancy Study Group (IADPSG). In 2010 the IADPSG Consensus Panel lowered the threshold for GD diagnosis. This move was based on the findings of one study – the HAPO study. This was an observational study looking at the risk of ‘adverse outcomes’ (see above) associated with 7 different categories of fasting BGLs; and with 1 hour and 2 hour BGLs after 75g glucose. The findings identified an association between fasting BGLs and the frequency of particular ‘adverse outcomes’ (see association vs causation in this post). The study reported: “frequencies in the lowest and highest [of the 7 fasting BGL] categories, respectively, were 5.3% and 26.3% for birth weight above the 90th percentile, 13.3% and 27.9% for primary [first ie. not VBAC] cesarean section, 2.1% and 4.6% for clinical neonatal hypoglycemia [low BGL], and 3.7% and 32.4% for C-peptide level [which reflects baby’s insulin levels] above the 90th percentile .” The amount that the 1 hour and 2 hour BGLs went up also influenced the frequency of ‘adverse outcomes’ – although the associations for primary c-section and neonatal hyperglycaemia (low BGLs) were weak.

The IADPSG Consensus Panel concluded that: “because associations were continuous with no obvious thresholds at which risks increased… a consensus was required to translate these results into clinical practice.” And so the new GD diagnostic threshold was created: OGTT results of BGL ≥ 5.1 mmol/l fasting or ≥ 8.5 mmol/l two hours after 75g glucose load. These thresholds are based on the average BGL values that increased the odds of a big baby by 1.75 times. Whilst this threshold may reduce the rates of babies over 4kg, there is no evidence that it will reduce the rate of birth/newborn complications Bonventura, Ernest & Dee (2015).

WHO changed their recommendations to align with IADPSG’s. WHO even state in the recommendation that the quality of evidence to support this new threshold is ‘very low’, and the strength of the recommendation is ‘weak’. This threshold results in up to 18% of pregnant women meeting the criteria for GD (previously 5%). Kevat et al. (2014) raised a number of concerns about the impact of the lower threshold for Australian women – many of which can be applied to other populations. However, despite an initial wave of concern from care providers, consumers, maternity organisations and researchers – these new thresholds made it into clinical guidelines and practice worldwide. A recent Australian study examined the impact of introducing the new thresholds and found that: “There was an increase in annual incidence of GDM of 74% without overall improvements in primary health outcomes. This incurred a net cost increase of AUD$560 093. Babies of women with GDM had lower rates of neonatal hypoglycaemia and special care nursery admissions after the change, suggesting a milder spectrum of disease.”

Treating the label

Once a woman has been labelled with GD she is usually diverted into ‘GD-centred’ antenatal care. There is often stigma attached to having GD, and additional medical surveillance and restricted choices regarding birth setting. Management of GD centres on keeping the BGLs within a certain range via diet and exercise, and/or insulin medication. The issues around dietary recommendations are a whole other issue that I can’t fit into this blog post. Long story short – the usual GD recommendations involve a high carb (ie. sugar) diet. Alternatively, Lily Nichols has written a couple of great books about diet in pregnancy and for GD (see below in further resources).

Although there are varying opinions about what BGLs should be maintained by women diagnosed with GD (Bonventura, Ernest & Dee (2015). In general the fasting BGL target is around 5.0-5.5 mmol/l fasting and the 2 hour post meal BGL is 6.7-7.1 mmol/l (by capillary blood, ie. finger prick test). Not surprisingly, hypoglycaemia (low BGLs) is a common problem for women trying to keep their BGLs within this range.

WHO summarised the evidence into the effectiveness of GD treatment. The only outcome categorised as ‘high quality’ is that treatment for GD reduces the chance of having a  baby 4kg+ (number needed to treat NNT = 11.4 to prevent 1 large baby). However, the evidence indicating a reduction in shoulder dystocia is of ‘low quality’ (NNT = 48.8 to prevent one shoulder dystocia). There is ‘moderate quality’ evidence that treatment reduces the chance of hypertension (NNT 18.1) and pre-eclampsia (NNT 21). For all other outcomes evidence was ‘moderate’ to ‘low’ quality. Bear in mind the research in the WHO summary was carried out before the new lower GD thresholds were introduced. A more recent Cochrane Review compared lifestyle interventions (diet and exercise) with ‘usual’ care or another intervention and found no difference in any outcomes except the size of the baby.

Labour and birth care for women labelled GD

The IADPSG Consensus Panel acknowledged that the “bias of caregivers toward expectation of adverse outcomes may increase morbidity due to increased intervention” for women diagnosed with GD. Women are often coerced into early induction of labour or even c-section because they have been diagnosed with GD. By coerced, I mean they are advised to have an intervention, rather than discussing the risks and benefits of various options, and their individual situation, then making their own decision.

Large-scale research exploring birth outcomes for GD tends to focus on the label rather than on BGLs. This results in 3 groups of women being mixed into the research sample:

  1. women with pre-existing diabetes only diagnosed in pregnancy
  2. women diagnosed with GD who had high BGLs during pregnancy
  3. women diagnosed with GD who maintained normal BGLs during pregnancy

For this mixed up group of GD women a Cochrane Review concluded: “There is insufficient evidence to clearly identify if there are differences in health outcomes for women with gestational diabetes and their babies when elective birth is undertaken compared to waiting for labour to start spontaneously or until 41 weeks’ gestation if all is well.” (the ’41 weeks’ is because induction at this gestation tends to be standard for all women).

However, things look different when we consider women based on what their BGLs have been in pregnancy rather than their GD label. In this case there are 2 distinct groups:

1. Women with normal BGLs (and a GD label)

These women do not have babies effected by high BGLs – because they didn’t have consistently high BGLs during pregnancy. Their babies are as likely to be over 4kg as women without GD. They should be cared for in the same way as women without a GD label because their ‘risk profile’ is the same. For this group of women induction is not supported by evidence or clinical guidelines. WHO recommend that induction of labour should not be offered for GD unless there is evidence of other abnormalities occurring, such as abnormal blood glucose levels. ACOG (US) state that “women with GDM with good glycemic control and no other complications are commonly managed expectantly until term.” Queensland Health (Australia) recommend that if blood glucose is well managed, there is no indication for induction for gestational diabetes. Despite this clear guidance women, are often booked in for an early induction by their care provider based simply on their GD label.

2. Women with abnormal BGLs (and a GD label)

This group of women are at increased chance of experiencing complications associated with high BGLs during pregnancy (see above). However, even for this group of women there is a lack of evidence to support induction. A paper by Berger and Melamed (2014) discusses the research relating to the timing of birth for women with GD, including the risks of induction for women and babies with GD. Like the Cochrane review above, they found inadequate evidence to support induction of labour for women with GD and concluded that “until such data are available, the clinician should consider the maternal, fetal and neonatal implications of induction of labour versus expectant management, involve the patient in the decision process and as usual follow the maxim of ‘‘first do no harm.’’

The main concern regarding high BGLs in pregnancy is the size of the baby (see above). This is often used as the reason for recommending induction. Babies with big shoulders are more likely to experience shoulder dystocia. For example, in non-GD pregnancies, shoulder dystocia occurs with around 1% of babies weighing less than 4kg compared to 5-9% of babies weighing over 4kg (Politi et al. 2010). These figures may be higher for babies subjected to high BGL in pregnancy because of the distribution of their additional weight (ie. upper body and shoulders). However, increased shoulder dystocia rates may also be partially due to the interventions women with suspected big babies experience. For example, if a care provider suspects a ‘big baby’ the woman is more likely to experience interventions (syntocinon, c-section, instrumental birth, etc) and complications regardless of whether her baby is actually big (Sadeh-Mestechkin et al. 2008; Blackwell et al. 2009).

Not surprisingly, induction before 40 weeks does reduce the chance of shoulder dystocia. A baby will be smaller before 40 weeks than after 40 week, and therefore statistically less likely to get stuck. A Cochrane Review comparing induction of labour before 40 weeks for a suspected big baby with waiting for spontaneous labour, found that induction decreased the incidence of shoulder dystocia from 6.8% to 4.1%. However, they also found an increased rate of severe perineal tearing in the induction group of 2.6% vs 0.7% in the spontaneous labour group; and an increase in the treatment of jaundice for the baby (11% vs 7%). Both NICE guidelines and WHO guidelines state that induction of labour should not be carried out simply because the baby is suspected of being big. Which is interesting because both guidelines support induction in the case of GD with high BGLs where the only significant risk factor for birth is a suspected big baby.

Women with high BGLs in pregnancy need to consider the risks of possible shoulder dystocia with the risks of induction (see Berger and Melamed 2014 ) and their own individual situation and preferences. Many women with abnormal BGLs can and do have physiological births, however most follow care provider recommendations and have their labour induced. The following are some suggestions for reducing/managing complications associated with birth for women who had high BGLs in pregnancy. Most of these suggestions can be applied to physiological labour or induced labour – although an induced labour is likely to result in a smaller baby.

  • Maximise the size of the pelvis – avoid positions that restrict the movement of pelvic bones (eg. don’t sit on the back of the pelvis)
  • Maximise the ability of the baby to rotate – A mobile mother offers lots of opportunities for baby to move – water immersion is good for this. Resting space between contractions also allows the baby to move when the uterus is relaxed. If syntocinon is regulating contractions, make sure there is a good ‘resting space’ between the contractions (no more than 4 contractions in 10 mins). If the woman has an epidural her care providers / support people will need to assist her to move her pelvis (eg. pelvic rocking using the drawsheet or towel).
  • BG management – if the woman is insulin dependent it may be necessary to check BGLs during labour.
  • Avoid interventions that cause wounds eg. c-section or episiotomy. High BGLs can interfere with healing and increase the chance of infections.
  • Avoid any interventions that interfere with instinctive behaviour as the woman pushes her baby out. If she has an epidural then avoid directed pushing until the baby’s head is on the perineum – and then keep it gentle with spaces in between for re-oxygenation of mother/baby and a chance for baby to rotate and move. Do not pull on the baby’s head immediately after it has birthed – this can wedge the shoulders into the pelvis before they have had a chance to rotate. If there is no change with the next contraction (no rotation or descent) – then suspect shoulder dystocia. and manage accordingly.
  • After birth do not remove the baby from their mother – this will result in a stress response that will burn up the baby’s glycogen (glucose stores). These stores will be needed as the baby re-balances their metabolism. Any resuscitation should be done with mother and baby together.
  • Prolonged skin-to-skin with mother will stabilise the baby’s heart rate and temperature; reduce stress; and encourage early breastfeeding – all great for maintaining BGLs.
  • Ensure the baby feeds early and often. Colostrum provides a nutrient dense package of glucose to help the baby keep their BGLs within a normal range. Even a few drops can increase the baby’s BGLs significantly. Woman can express and store colostrum at the end of pregnancy to provide additional colostrum for the first hours after birth.
  • The baby may have their BGLs monitored as they adjust to the withdrawal of high maternal BGLs. Any monitoring and/or management can be done with mother and baby together. Separating mother and baby is detrimental for all kinds of reasons, including BGL stabilisation.
  • Observe the baby during the first week for jaundice. As discussed above, significant jaundice is fairly common for babies who produced high insulin during pregnancy. The baby may need light therapy to resolve their jaundice.
Breastfeeding
How to reduce the chance of hypoglycaemia (low BGLs)

Summary

High BGLs in pregnancy alter the growth and development of the baby, increasing the chance of particular complications occurring. However, the label ‘gestational diabetes’ is problematic because it is poorly defined and there is a lack of evidence to demonstrate that labelling and treatment improves outcomes. Guidelines do not support induction of labour for GD unless BGLs are high. Inducing women before 40 weeks with high BGLs reduces the chance of a large baby and shoulder dystocia, but increases the chance of other complications. Labour and birth care for women with high BGLs should centre on minimising the chance of shoulder dystocia, and supporting the baby to regulate their own BGLs after birth.

Additional Resources

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Midwife and Academic
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39 Responses to Gestational Diabetes: beyond the label

  1. Thank you So needed.

    Also – the damage incurred to baby forever after – whilst this ridiculous ‘test’ is done. (Plus the panic mum goes into)

    (And if not careful follows the ‘eat more bread’ advice?

    Warm wishes Heather

    *Best wishes,*

    *Heather Bruce *

    Transformative Energy Body Worker Founder of Heather’s Gentling Way

    Accredited Mercier therapist Arvigo® /Maya Self Care teacher, Certificated and Pregnancy Arvigo® worker

    http://www.heatherbrucehealing.com

    10 Kitchener St, Coorparoo, 4151, (Brisbane) AU

    (07) 3899 2274

  2. Jessie says:

    Another fantastic, clearly written resource. Thank you!

  3. anastasia says:

    I always appreciate your posts and devoured them when I was pregnant. I didn’t have GD but I did have an 11 lb baby at home in the water with no tearing 😉 My claim to fame. I have seen some friends be induced for GD citing the reason of a big baby and can’t help but contrast my experience.

    Blessings to you ✨

    Sent from my iPhone

    • Thanks 🙂 11 lbs is very big! I might write a post on ‘big babies’

      • Deirdre says:

        My boy was 5.5kg/12lbs, vaginally delivered, no intervention, no pain relief by choice and all well. Luckily for me the hospital underestimated his size during pregnancy at a mere 10lbs other wise we might have had a different experience.

  4. Krystle says:

    Interesting read. I landed myself a GD label in the public system because my 1 hour result was 0.1 over the limit. Was well within normal by 2 hours. This lead to much stress, instant dismissal from a birth center and insistence that if I don’t go through the obstetric team and dietary team I’d end up with a dead baby (don’t you love how obstetricians are so supportive?!). Long story short, found a wonderful independent midwife and had a wonderful homebirth with a 3.4kg bub.

  5. Thank you for writing this helpful and informative post which I will definitely be using as an information source with my clients. During birth care, I presume you are taking as read optimal cord clamping (“waiting for white”) as a given as this would assist the baby’s perfusion and assist in the break down and excretion of bilirubin. Brilliant piece and will be sharing. Please keep writing!

  6. funhomeweb says:

    Thankyou for this very informative and well explained, evidence based article.
    I have recently supported a woman who was being induced at 35+4 and who had normal blood glucose during the beginning of her induction. I do not yet know the outcome of her induction. But it is so important that women have this information so that they can make their own decision. Sadly this isnt the case at present. Language of care givers can be very coercive.

  7. Jen says:

    I was dx with GD during my 2nd pregnancy. I had taken my 3hr glucose test and was told I failed 1/4 draws but passed. Switched providers to vbac. That ob said I failed. I tested my bs 4x a day with perfect results. Almost a month in, their own diabetes specialist asked why in the world I was testing as my numbers were normal. She spoke with my ob, who then had a nurse call to say my numbers were out of control & stuck me on meds. Said meds dropped my baby dangerously low and I nearly crashed. When I reached my destination( after quickly eating a candy bar to bring up my sugar) tested my bs at 50! The ob refused to take the diagnosis off my chart. That birth ended in a bullied section after being induced for a ” big baby” who was ONLY 8 10. I took and passed the GD test with #3 & was still labeled GD baby was 8 12 and my first vba2c. I refused the test with #4 and tested my bs with normal numbers which I shared with my provider and she was 10#5 oz. Again, my chart said I had GD. Not one of my babies had any issues often associated with GD. With #2 they CLAIM he had bs issues but REFUSED to tell me his numbers, just threatened to put him in the NICU. If I get phone again, im testing at home again. It doesn’t matter if I think and pass their test, they’ll label me whatever they want.

  8. Jennifer McNeel says:

    Thanks, as always, for such an informative piece! I had been keeping my sugar intake low for years before getting pregnant, so I cordially refused the glucose test because I was worried about getting a false positive (everyone is expected to take it in Spain, and I was already sceptical as I was under 35 and with a BMI of 19). Instead, I kept a chart of my blood sugar levels before and after meals for a full week; the gynaecologist at my next appointment cordially refused to look at my chart. She also reminded me that I would be in the high-risk unit no matter what since my pregnancy was achieved through IVF.
    Some time after that, I changed hospitals. I was pleased with the change overall, but found that too many midwives were obsessed with the notion that you could not gain more than 9 kg in pregnancy. I don’t know what evidence they based this on, but I measure 1.74m and it just sounded ridiculous. Amid much head-shaking and big baby shaming, I gained 12 kg.
    My big baby, born without interventions at 39+4, weighed 2.6 kg.

  9. Kim says:

    I myself unfortunately got labelled with GD after 20 long weeks of extreme morning sickness. I was considered boarderline GD and throughout my whole pregnancy it was managed diet only. I think I only ever got two high readings.

    Unfortunately during that time I became very distressed from the effects of the morning sickness and the bright red DIABETIC sticker on the front of my pregnancy notes just pushed me over the edge into madness which saw me at my lowest point and in complete guilt panic testing my bloods on the hour and I stopped eating altogether which ended up in me being admitted for a drip.

    They kept telling me my baby was measuring large at scans and told me that I’d be looking at my baby being over 11lbs. I even had a private scan done also and they told me the same. By this point I was even more distressed than before.

    Anyways long story short, was induced early at 37 weeks due gallstone problem in which the gallbladder was removed two weeks after the birth. My birth also ended in an emergency c-section and my prophecied 11lb baby ended up being a healthy 7lb baby boy who is now 9 months and thriving.

    More research and support needs to be done into GD to ensure Mothers are receiving the right care to meet the individual needs of their pregnancies rather than being shuffled into unecessary practices.

    To all other GD mothers, look after yourselves and do what is best for yourself and your baby.

  10. nataliemeade2015 says:

    Thank you for your hard work!!!! WOoohooo!

    I have seen so many birth clients (Independent Birth Education) “diagnosed” with GD.. and they are then recommended and feel pressured/scared into monitoring their levels three-four times a day – by bloods ! Which of course is the last thing a pregnant woman wants to do everyday. These clients often NEVER get another reading OUTSIDE of normal and yet STILL get treated as high risk and pressured into ongoing extra tests, inductions and many other interventions.

    I will look forward to knowing I now have an accurate, recent and well written article to assist them to understand the circumstances and choices around their health management and risks.

  11. jackemeyer says:

    I am not a midwife, yet as the sperm donor 😉 I did continuously prepare myself to be fully involved in my pending child’s birth; further, I continue to keep up-to-date w/ literature on some of the topics b/c I enjoy helping other newly pregnant partners succeed w/ birthing a healthy baby and momma in USA-context of big box hospital/birthing-center culture. Thus, I will plop a comment here as though I too were a midwife (further, I will share my comment with our hired midwife, who coached us during the birthing of our super-cute baby, 23 months old at this writing).

    Given my partner’s comprehensive $15kUSD/yr insurance coverage (USA), she decided to meet with Ob teams (three over the course of 41 weeks). We each having lived for 45 yrs on this glorious planet meant she was labeled “high-risk” and treated as a diseased and handicapped individual, even as her biomarkers came back excellent throughout the 41 weeks, including fasting BGL of 3.6 – 3.9 mM & normal peak post-prandial responses coming down to 5.5 mM within 90 minutes. Note: We did not bother w/ any of the institutional OGTTs; rather, once every two weeks, we both (using the same $25 glucose meter & $2/strips, w/ I as sole control subject) constructed multiple-hour capillary glucose curves using the ancient practice of … drum role please … eating our normal meals!

    While we were careful to not mindlessly compare the epidemiological OGTT data to our glucose responses to delicious & nutritious meals, I think we collected contextually relevant data that could be reasonably “acted upon” if comparisons to epidemiological averages suggested a need to intervene. I think this could be correctly referred to as an “evidence-based approach”.

    Last, I think any “normal” healthy (or even completely naive) pregnant person should be offered the opportunity to be coached/instructed on how to measure capillary glucose, and any partners involved too. I think of it as part of the process of self-awareness, even self-ownership. Sovereignty.

  12. kixi says:

    “BGLs are only high in early pregnancy in poorly controlled, pre-existing diabetes”

    I have to disagree with this, as so many other GDM mums. My blood sugars were perfectly fine between pregnancies, and now at 14 weeks I’m already getting high readings.

    • That’s interesting – pregnancy hormones are not usually high enough to cause insulin resistance until 20 weeks. Have you had an HbA1c test?
      The statement relates to current medical knowledge and clinical guidelines rather than my opinion.

      • kixi says:

        Yup. I’ve also asked in the GD UK group and it’s plenty of us!

        • That is something that needs to be looked at then. If women have high BGL in early pregnancy it can effect the development of the baby during that critical stage ie. as the organs form. That increases the risks of congenital abnormalities.

          • kixi says:

            It seems like it is looked at, depending on where you are. In my trust they recommend you start testing at 14 weeks.
            Do you have a reference for the 20 week definition?

          • Yes they do test earlier if you have previously had GDM or have risk factors.
            The reference is from the text book Medical disorders in pregnancy: a manual for midwives. However, the 20 weeks is also stated in guidelines etc. If you can find me a different source stating something different I will change the statement. However, for most women due to the physiology/hormones they are unlikely to get insulin resistance before 20 weeks… unless they are already insulin resistant.
            When I say ‘looked at’ I mean scientists needs to re-examine the understandings of physiology/pathophysiology (that are stated in books and guidelines) if lots of women experience high BGL before 20 weeks. The current recommendations re. timing of testing are based on this understanding of BGL rising after 20 weeks.

  13. calliona says:

    Many thanks for this informative article. It’s very engouraging for me. I have been diagnosed with gestational diabetes at week 28 (and very grateful for this, as I didn’t feel well after eating fruits) after a GGT (due to my age, over 40 – apparently 12 % of women over 40 have GDM). BGLs are stable now and I hope to avoid induction at week 39, but it won’t be easy.
    One thing – you write “Long story short – the usual GD recommendations involve a high carb (ie. sugar) diet.” Is this correct? I was adviced to have a high-protein based diet. As this was already the case, I had lowered my carb intake even more so that eventually I was advised have more carbs (while at the same time I took a bit more insulin).

  14. RN Runner says:

    You never address #3, women with normal BGLs

    • Women with normal BGL do not have any addition risks regardless of whether they have the label GDM. This is the whole point of the blog post. Normal BGL = no need for the baby to increase insulin production.

  15. Fantastic article, makes sense all round, keep up the good work Rachel.

  16. aussiemidwife says:

    As always I enjoy reading your posts. I have been researching the thresholds for diagnosis of GDM that are now stock standard in our maternity care. I notice in your comments above that you say that the one hour result should not be used in diagnosis. WHO and multiple others are including the one hour in their diagnostic criteria. Is there some references you can point me to that support excluding the one hour result?

  17. Marissa says:

    Thank you for the article!! It is so frustrating to have this label. I feel like I’m wearing the Scarlet Letter 😦 I am looking on your blog for information about NSTs… I know they are not evidence based to be necessary in women who are diet controlled, but yet some practices still choose to do them once, or even twice per week starting at 32 weeks! I am GD, diet controlled so far at 28.5 weeks and would like to do as LITTLE intervention as possible (no NSTs or additional ultrasounds before 40 weeks, no induction, no meds, etc.) provided I can remain without further risk factors. Do you have anything you can share about NSTs? I have found research on the risks for ultrasounds. Thank you!!

    • There is no evidence to support routine NSTs for women with normal BGLs (regardless of their label). The intervention is done ‘just in case’ and because despite all the evidence there is a belief that u/s can accurately estimate the size of a baby. It is up to you whether you want to accept the offer or NSTs. And you do not have to provide your care provider with a reason for declining their recommendations. However, they have to provide you with good evidence and information about any intervention they recommend.

  18. Tom says:

    Hi Rachel,
    Are you aware of the recent case-control study which seems to suggest that there is a greater risk of term stillbirth for women with risk factors for GD who are not screened, compared with no additional risk for those that are?

    And also that women with raised BGLs have a 4-fold increased risk of term stillbirth, compared with those screened and treated as GD? This study seems to demonstrate that women do in fact very much benefit from being “labelled” as GDM and treated accordingly.

    https://obgyn.onlinelibrary.wiley.com/doi/abs/10.1111/1471-0528.15659

    • Thanks for sharing this – I can’t access the full article. Can you quantify 4-fold into something meaningful for readers ie. from x.x% to x.x%… I am guessing we are still talking extremely small numbers. Women need to have this information to make an informed decision about whether they want routine screening or not. Also what other outcome measures/risks were looked at? Again necessary information for individual decision making.

      Screening or not (getting a label) is up to individual women… and they need adequate information rather than fear/risk based information such as ‘4-fold’ – NICE provide some good guidance for care providers about presenting statistics in an objective rather than fear-mongering way. Women also need to consider the risks that come with the label (as discussed in the post) – not just one small risk (stillbirth according to this study).

      • Tom says:

        Thanks for quick reply Rachel! I do appreciate the need for clear and not fear-mongering stats, but unfortunately the world of medical studies doesn’t always (often!) work in this way (as I’m sure you know, not trying to patronise you!). We rarely get huge, well-powered RCTs because thankfully our worst outcomes are indeed uncommon. We have a patchwork of studies suggesting relative risks, and even big population studies may not have been done in the UK. When big population studies are done, people often complain that they can’t be trusted because the populations aren’t directly comparable to the UK, or important details got lost in the compound measures!

        As a case-control, this study can’t comment on incidence/prevalence – the cases were all chosen specifically because they suffered a stillbirth, the controls didn’t, this wasn’t a sampled population. So we can’t derive an “x to y%” risk increase.

        They excluded controls with congenital abnormalities or multiples, but that’s a relatively low proportion of stillbirths. Also, whilst the study says “late stillbirths”, their inclusion criteria was >\=28 weeks; that seems more like all stillbirths to me (or at least most – perhaps trying to distinguish between miscarriage for a lay reader).

        So, crude calculation… knowing that the rate in the UK is approx. 4 in 1000, and let’s say 1 in 1000 is either 24-27+6 weeks or congenital abnormality (which is probably a gross overestimate), that’s going from 0.4% risk to a 1.6% risk (again, more likely an underestimate).

        According to RCOG guidance on describing risk, that takes it from “uncommon” to “common” (although I would never describe it in those terms), but still, I really don’t think that difference is to be sniffed at. Given that a busy GDM clinic might see over 30 women, that would be equivalent to 1 woman in every 2 clinics experiencing stillbirth if they didn’t receive screening/treatment, compared to 1 woman in every 8 clinics with treatment.

        • Thanks Tom. That helps to put it into perspective. Research is very problematic in maternity care – I wrote about that here: https://midwifethinking.com/2017/01/23/research-bias-and-maternity-care/

          Perhaps the label of GDM would not be such an issue if it didn’t then result in a pathway that includes over intervention – in particular early IOL. The risks of those interventions also need to be considered eg. increased c-section rates = increased subsequent stillbirth rate etc.

          BGLs are clearly an issue and perhaps all women should be supported to have optimal nutrition in pregnancy ie. evidence based nutritional information. Our maternity systems are set up to identify and treat rather than promote wellness and prevent complications.

          I will see if I can get access to the article via my uni and include it in the post.

  19. Angel Sheds says:

    Interesting that nowhere you mention stillbirth which is what we are threatened with if we don’t agree to induction. Was there anything to suggest this in the research?

    • Increased rates of stillbirth used to be associated with pre-existing diabetes rather than GD. So older studies that just looked at ‘diabetes’ (combined groups) would have higher rates (still very low).

      However, the latest research distinguishes between the two types of diabetes and the risk of stillbirth for GD is not higher. It is also not higher for pre-existing diabetes in recent studies… because we are better at planning and supporting pregnancies in that group of women. I discuss this and the research in my boom 😉

      Sounds like who ever is threatening is out of date re. evidence based recommendations.

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