A new peer-reviewed study from Bar-Ilan University has shown that studying a pregnant woman’s gut microbiome can predict as early as the first trimester whether she will later be diagnosed with diabetes mellitus (GDM).
This is a significant result that could lead to better prevention and treatment of the serious disease that can lead to complications for mothers, their unborn children, or both, said the scientists.
The study applied a machine learning model to fecal and saliva samples and medical records of a cohort of 400 Israeli women who were still in the first trimester of their pregnancy. Those found to have specific combinations of bacteria, types of fatty acids, and inflammatory markers in their guts had a significantly higher chance of developing GDM.
“When writing the paper, we succeeded in 83 percent of the cases in predicting which of the women would develop the condition,” said Professor Omry Koren of the Azrieli Faculty of Medicine, the study’s lead researcher. .
As of today, pregnant women are usually only tested for GDM in the second trimester, at an average of 26 weeks. This is the period during pregnancy when insulin resistance increases.
GDM is diagnosed worldwide in approximately 10% of pregnant women without a known history of pre-diabetes or diabetes. In some cases, diabetes can be managed with diet and intense exercise, but in others, insulin injections are required. Although GDM goes away after the baby is born, there is a higher risk that the mother will later develop Type 2 diabetes and that her baby will be obese.
Professor Omry Koren. (Courtesy of Bar-Ilan University)
“We know that 50% of patients with GDM will become diabetic within 10 years of their pregnancy,” said Professor Eyal Sheiner, chair of the department of obstetrics and gynecology at Soroka University Medical Center.
Sheiner, who was not involved in the study, said that investigating GDM prevention by scrutinizing gut microbiota – rather than blood for elevated sugar levels – was an interesting and worthwhile approach, and he looked forward to seeing where it would lead. will be the research.
Rebecca Einstein Schorr told The Times of Israel that she was surprised to hear of this scientific advance and regrets that the information was not available when she was pregnant with her three children, who are now 15, 19, and 22. The 52 year old. The Emmaus, Pennsylvania resident had GDM in each of her pregnancies.
“During the first pregnancy, especially, it was scary… you feel like your body is betraying you. You cannot keep your child safe. He was very upset,” she said.

Rebecca Einstein Schorr. (Courtesy)
Her diagnosis came when Passover was near. She worried that if she ate too much matzah and other traditional holiday foods that were rich in carbohydrates, she could send her fetus into glucose shock. He enjoyed the holiday and looked forward to the rest of the pregnancy.
Schorr fell into the 10% of women with gestational diabetes for whom diet and exercise aren’t enough and who need insulin.
“So here I was, just a completely regular pregnant person, and boom! Fast forward and I am checking my blood sugar all the time and have to take insulin throughout the day. That was a huge mental adjustment. Of course, the main motivation was to promote the gestation period, to preserve the life of the child. But diabetes is a full-time job,” she said.
Koren spoke to The Times of Israel from Valencia, Spain, where he is on a year-long research sabbatical studying the bacteria in breast milk. He explained that an additional aspect of the GDM study published in Gut involved feeding the feces from the first trimester study subjects into germ-free mice.
“These are mice that we grow under special conditions. They had never seen bacteria in their lives,” said Koren.
The mice that received feces from the women who developed GDM eventually developed higher glucose levels than the mice that were fed the feces of women who did not develop the condition.
To test whether this is not a phenomenon limited to Israeli women, Koren and his team collaborated with researchers in the US and Finland. Fecal samples were collected from women in their first trimester from those countries and injected into the special mice. The results were the same.
“This showed that this is a universal phenomenon,” Koren said.

An illustrative image of a diabetic patient measuring blood sugar levels. (Maya23K, iStock by Getty Images)
He reported that efforts are underway through Bar-Ilan University to establish a company that would offer products to predict pregnancy complications, including gestational diabetes. But in the meantime, his best advice for pregnant women is to stick to a healthy, low-sugar diet from the start, and for the medical team to keep an eye out for signs of insulin resistance before the 26th week.
“In Israel, we measure the fasting blood glucose of all pregnant patients. If a woman has a glucose level higher than the threshold, we don’t ignore it,” Sheiner said.
Schorr, who now has Type 2 diabetes, would have welcomed a GDM prediction tool when she was expecting her children.
“Prediction would help psychologically and emotionally because there is more preparation time. When you are diagnosed much later in your pregnancy, you have a lot of information thrown at you that you have to process very quickly and scramble,” she said.