The Data Debate on Diabetes in Pregnant Women!

Diabetes data debate

Questions about diagnosing diabetes in pregnant women have sparked data-driven controversy. Some researchers say that as things stand, we could actually put mothers and babies at risk.

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Thousands of Australian women may have received the wrong treatment for gestational diabetes (GDM), which could hurt their babies as the medical community has a major disagreement over how to detect the disease.

Hormonal changes during pregnancy can cause some healthy women to develop diabetes. If properly managed, it is usually harmless to women and babies; untreated, it can lead to miscarriages and stillbirths.

The debate has been simmering for years, focusing on who needs treatment. A recent study published in the New England Journal of Medicine showed that the tests used in most Australian hospitals were so severely overdiagnostic to pregnant women that many pregnant women classified as diabetics who may not be diabetics.

This puts them at risk of treatment that could impair fetal growth.

"More women have been diagnosed with gestational diabetes than before – up to 25% in some communities. There is currently no clear evidence that this benefits women or infants."

Over-intervention may pose a risk to smaller infants.

In an article just published in the Australian Medical Journal (MJA), Professor Jenny Doust of the University of Queensland has identified a number of other risks of overdiagnosing gestational diabetes, including "the risk of (and) more invasive forms of childbirth for women diagnosed, and the potential harm to babies from restricted diets and use of insulin, such as being born with too little weight, including an increased risk of infant hypoglycemia".

Split the board of directors of ADIPS.

David Simmons, an endocrinologist and professor of medicine at the University of Western Sydney and Shub's colleague on the ADIPS board, believes the one-step test (explained below) has saved countless women who would otherwise have missed the two-step process. He and three other board members submitted a review article to MJA questioning a few points raised by Doost and his colleagues.

Test

The vast majority of pregnant women in Australia use a one-step test to diagnose it, drinking 100 grams of sugary drinks after fasting and then measuring their blood sugar through a blood test.

Australian medical guidelines stipulate that women should be treated if their blood glucose levels reach or exceed 5.1 mmol/L after fasting, 10.0 mmol/L or more after drinking a beverage for one hour, and 8.5 mmol/L or more after drinking alcohol at 24 to 28 weeks of pregnancy.

A second two-step test, which does not require a woman to fast overnight, instead drinks 50 grams of sugary water in the morning (instead of 100 grams) and then a blood test an hour later to check for glucose.

Those who showed abnormal results had a full three hours of oral glucose tests (pregnant women fasted overnight, gave 100 grams of sugar water to drink in the morning — and then had blood tests every hour for three hours to see how well she tolerated glucose).

Stosh entered the international arena after the publication of a recent study in the United States that found no benefit for women or infants by passing a one-step test instead of a two-step test.

The new study, based on a randomized study of about 23,000 American women with a similar population to Australia, screened half of the women using one-step criteria and the other half using two-step criteria. Of the women assigned to the one-step approach, 16.5 percent were diagnosed with gestational diabetes, but only 8.5 percent of women assigned to the two-step test.

"By the time we reached the 24 and 28 weeks of gestational diabetes, which are traditionally tested, the damage had already been done."

Experts like Doust argue that treatments and interventions for gestational diabetes should be based on a case-by-case basis, incorporating the individual's overall risk profile, rather than just lowering the glucose threshold to such a level, which will always grab most women, causing inconvenience at best, and at worst being more likely to harm the baby.

Susan de Jersey, associate professor at the University of Queensland and a senior certified practicing dietitian, said: "Blood sugar levels vary widely and can be affected by factors such as hydration, stress (and even poor sleep at night)."

"The challenge is to find out who benefits from treatment, and the two-step process is actually a way to identify women who are at higher risk on the first test and then perform a comprehensive oral glucose test for those high-risk women."

Like Doust, Jersey argues that treating people diagnosed with gestational diabetes based on very trivial outcomes can actually be harmful to both the mother and the fetus.

"An incorrect diagnosis can lead to women limiting dietary intake when needed and cutting off specific food groups." "The process of monitoring blood sugar (with a needle to the finger) can also create stress, which we know is not good for growing babies."

Over-intervention may pose a risk to smaller infants, whose growth trajectories may have been reduced due to treatments such as insulin injections. This can be particularly worrisome in cases where pregnant women are diagnosed with the disease. "Who's to say that small babies don't need more nutrients and glucose to grow and increase insulin resistance to drive this growth"?

How did we get here?

Much of the information we have about gestational diabetes comes from high blood sugar and adverse pregnancy outcomes (HAPO) studies. This was established after the International Association of Diabetes and Pregnancy Research Groups (IADPSG) published two randomized controlled trials (a 2005 study in Australia and a 2009 Langdon study) in the mid-21st century that showed that treating women with gestational diabetes could lead to better outcomes.

There is no clear evidence that changes in the one-step process benefit women or infants, and there are many downsides.

"These include financial and logistical impacts on health systems and women, such as more visits, more tests, insulin, glucose meters, more induction of labour, and the medicalization of normal pregnancies."

Another Australian study also found that "many [women] from rural and remote communities have to move to live near a hospital in the last month of pregnancy, which comes at a considerable cost to themselves and their families."

Professor Michael D'Emden, Director of Endocrinology at the Royal Brisbane and Women's Hospital of Australia, said our current question of the way we diagnose and think about gestational diabetes is based on the HAPO study, an epidemiological study that is "confused with an interventional study that looks at whether treatment is effective".

"The fundamental flaw in following the HAPO data is that the way the researchers defined the criteria for gestational diabetes for each blood glucose level used an entire population filled with the most at-risk populations." "Because of this, at least 60 percent of people diagnosed with a type of hyperglycemia, many of whom are actually at minimal risk." Our diagnosis of people with this disease is completely excessive."

D'Emden echoes Jersey's thoughts, fearing that a stage of the screening process is labeling and medicalizing many women, who are at very low risk in the worst case scenario.

"One study looked at young babies and found that they were at risk of developing metabolic diseases and cardiovascular problems later in life."

Is the importance of the Australian fasting test underestimated?

"The key that came up after the HAPO study was that fasting blood glucose was actually more important than the researchers thought." "About 50 percent of women with high fasting glucose levels pose a risk of worsening outcomes. The first step of the two-step approach, the 50 g glucose challenge test, completely ignores fasting glucose because it is a non-fasting test."

Glucose responses in oral glucose tolerance tests vary by ethnic group, and the IADPSG approach is designed to ensure equity between different ethnic groups.

Simmons currently leads the treatment of a fully randomized controlled trial of scheduled gestational diabetes mellitus (TOBOGM), which examines women with many risk factors at the beginning of pregnancy to see if they need treatment earlier — and he argues that the traditional (and current) view of gestational diabetes (which only occurs when insulin resistance increases during normal pregnancy between 24 and 28 weeks) no longer applies.

A great deal of work has shown that 40 to 60 percent of hyperglycemia and undiagnosed diabetes are present at the beginning of pregnancy, depending on ethnic groups and circumstances." "This means that by the time we reach the 24 and 28 weeks of gestational diabetes that have traditionally been tested, the damage has already been done."

Simmons argues that the discussion should not be about "the need to replace the current standard with 24 to 28 weeks, but rather use new data from TOBOGM to determine criteria for early pregnancy and then pass the best criteria at 24 to 28 weeks of pregnancy".

However, D'Emden suspects that while Simmons may be right, he needs to "finish the study first and then turn around and say we should test women by 24 weeks.""

All guidelines are based on the best data we have obtained from hapo studies and all say that diagnosis is made within 24 to 28 weeks. Before the PUBLICATION OF THE TOBOGM STUDY, THIS WAS THE STANDARD.

D'Emden argues that the medical community needs to re-evaluate how it diagnoses and treats women with gestational diabetes by looking at the original HAPO dataset and defining the risk based on all three glucose level readings, such as fasting for 1 or 2 hours.

We also need to separate high-risk women from low-risk women, pay more attention to factors such as age and weight, and change treatment accordingly.

A young, slender woman on a low-carb diet may already have higher glucose readings and is more likely to have a smaller baby. She shouldn't be treated the same way as a woman with multiple high-risk factors.

D'Emden advises: "The best approach is to establish a randomized controlled trial that studies the effects of dietary recommendations only with intensive interventions that bring people down to normal glucose levels."