A healthy gut might play an even bigger role in pregnancy than scientists once thought. New research from the University of Cambridge has found that a type of beneficial gut bacteria, Bifidobacterium breve, helps the placenta produce key hormones that support fetal growth and reduce pregnancy complications, at least in mice.
The study, published in the Journal of Translational Medicine, compared pregnant mice with no gut bacteria to those with Bifidobacterium breve in their system. Mice without the bacteria were more likely to experience pregnancy loss, fetal growth restriction and low fetal blood sugar. Those with Bifidobacterium breve had healthier pregnancies, with placentas that absorbed more nutrients and produced higher levels of critical pregnancy hormones, including prolactins and pregnancy-specific glycoproteins.
“Our results open up an entirely new way to assess the health of a pregnant mother and her developing fetus by looking at the mother’s gut microbiome,” said Dr. Jorge Lopez Tello, who carried out the work at Cambridge’s Department of Physiology, Development and Neuroscience.
The findings point to what researchers describe as a “remote control” relationship between the gut and the placenta. The team identified more than 150 biological processes and over 400 proteins that differed in the placentas of mice with and without the bacteria, suggesting that gut microbes may influence how well the placenta nourishes the fetus.
Although this research was done in animals, scientists believe it could eventually lead to new ways of detecting or preventing pregnancy complications in humans.
“Everybody ignores the placenta — after nine months of pregnancy it just gets thrown in the bin,” Lopez Tello said. “But now we understand more about how it works, in the future pregnancy complications like gestational diabetes, preeclampsia, miscarriage and stillbirth might be prevented simply by adjusting the mother’s gut microbes to improve the function of the placenta.”
Professor Amanda Sferruzzi-Perri, senior author on the study, said the work opens the door to microbiome-based strategies that could improve outcomes for mothers and babies.
“Our research reveals a whole new layer of information about how pregnancy works, and will help us find new interventions that can improve the chances of a healthy pregnancy for mother and baby,” she said.
“It’s exciting to think that beneficial microbes like Bifidobacterium — which naturally support gut and immune health — could be harnessed during pregnancy to improve outcomes,” added Professor Lindsay Hall of the University of Birmingham. “Using something like a probiotic offers a promising alternative to traditional therapeutics, potentially reducing risks while enhancing wellbeing in mother and baby.”
The researchers caution that more studies are needed to confirm whether the same effects occur in humans. Still, the findings highlight the growing recognition that gut bacteria influence far more than digestion, including how the body supports new life.
This research was supported by the Wellcome Trust, the Royal Society, the Biotechnology and Biological Sciences Research Council, the Lister Institute of Preventive Medicine, Science Foundation Ireland and the Community of Madrid.