Gut microbes can help diagnose gestational diabetes in 1st trimester - study

Gestational diabetes – a potentially dangerous condition for the mother and fetus – can be diagnosed as early as the first trimester of pregnancy, months earlier than typically detected, according to a new study at Bar-Ilan University (BIU) in Ramat Gan.

GDM (gestational diabetes mellitus) is a condition in which women without diabetes develop glucose intolerance during pregnancy. Affecting about 10% of pregnant women worldwide, it occurs when the pancreas cannot produce enough insulin to balance insulin-inhibiting effects of placental hormones, and is currently not diagnosed until the second trimester of pregnancy. The incidence of GDM is increasing worldwide, and it can lead to type-2 diabetes later in the mothers.

Led by Prof. Omry Koren of the BIU’s Azrieli Faculty of Medicine in Safed and a team of Israeli and international researchers, the study is one of the first to show reliable prediction of GDM months before it is typically diagnosed.

It has just been published in the journal Gut under the title “Gestational diabetes is driven by microbiota-induced inflammation months before diagnosis.”

What does gut microbiota have to do with gestational diabetes?

There are marked differences in the first trimester gut microbiota – the bacterial population found in the digestive tracts of humans and animals – of women who do and do not develop gestational diabetes later. These differences are associated with inflammatory markers, with women who develop GDM exhibiting higher inflammation and lower levels of beneficial metabolites.

The team studied 394 pregnant women aged 18 to 40 years, who were recruited when they were 11 weeks pregnant, at women’s health centers of Clalit Healthcare Services in the Dan and Petah Tikva districts in 2016-2017.

In the study, fecal and blood serum samples were collected from the women during their first trimester. Their microbiota, metabolite, inflammation and hormone profiles were characterized. Smoking, diet and other lifestyle habits were recorded and clinical/medical data were compiled from digital health records.

Using the results of these characterizations, combined with other collected data, Prof. Yoram Louzoun at BIU’s mathematics department and the Gonda (Goldschmied) Multidisciplinary Brain Research Center built a machine-learning model that can accurately predict which women would go on to develop GDM, and which would not.

The researchers then showed in animal models that transferring the first trimester feces of women who went on to develop gestational diabetes results in the transfer of the diabetes phenotype to germ-free mice, suggesting that the gut microbiome has a role in mediating disease development. The microbiome model study’s findings were not specific to one population – for example, it could predict GDM in Chinese women, and the mice results were replicated in Finnish and American cohorts.

“Recognition of women at risk of gestational diabetes at an early stage of pregnancy may allow specific recommendations for prevention of the disease – currently by lifestyle modification and in the future perhaps by specific pre-, pro- and post-biotic supplementation,” Koren suggested.

If gestational diabetes can be prevented, there would be a major reduction in adverse outcomes of GDM, for mothers and their offspring, in both the short and long term, benefiting families worldwide.