Evidence that mother’s gut microbes aid fetal development found by Cambridge and East Anglian scientists

The first evidence of how a mother’s gut microbes could aid the development of the placenta during pregnancy and the healthy growth of the baby has been uncovered.

The study could lead to a method of combating pregnancy complications.

Scientists carried out research in mice, analysing how supplementation with a probiotic, Bifidobacterium bacteria, affected their pregnancy.

Gut microbes - collectively known as the gut microbiome - are known to play a key role in human health, combating infections and influencing our immune system and metabolism. They break down food and release active metabolites that influence the body’s processes.

But little has been understood about how such interactions impact fetal development.

Professor Lindsay Hall, from the Quadram Institute and University of East Anglia, and Dr Amanda Sferruzzi-Perri and Dr Jorge Lopez-Tello, from the University of Cambridge, sought to change this.

Prof Hall has previously shown how providing specific probiotics can help premature babies. These bacteria rise in numbers in the microbiome during pregnancy in both humans and mice. Alterations in the levels of these bacteria have been linked to pregnancy complications.

Dr Sferruzzi-Perri said: “Pregnancy disorders affect around one in 10 pregnant women. This is worrying, as pregnancy complications can lead to health problems for the mother and her baby even after the pregnancy.

“This study, carried out in mice, identifies the maternal microbiome as a new player in the communication between mother, placenta and fetus. Finding out how this form of communication works and how to improve it may help many women who develop pregnancy complications, as well as helping their developing child.”

The researchers used ‘germ-free’ mice - which lack any microbes – bred to allow comparisons with other mice with a normal microbiome.

They found that In the germ-free mice the fetus did not receive adequate sugar and failed to grow and develop properly.

But giving these mice Bifidobacterium breve improved fetal outcomes by restoring fetal metabolism, growth and development to the normal levels.

The absence of the maternal microbiome also hampered the growth of the placenta in a way that would affect fetal growth. Analysis showed key cell growth and metabolic factors that appear to be regulated by the microbiome and Bifidobacterium breve.

Dr Lopez-Tello said: “The placenta has been a neglected organ, despite it being vital for the growth and survival of the fetus. A better understanding of how the placenta grows and functions will ultimately result in healthier pregnancies for mothers and babies.”

The microbiome also affected key nutrient transporters, including those for sugars within the placenta.

Prof Hall added: “Our findings reveal that the maternal microbiome promotes development of the placenta and growth of the fetus. We think that this is linked to the altered profile of metabolites and nutrients, which affects nutrient transport from mother to baby across the placenta.

“Excitingly, it appears that adding in a probiotic Bifidobacterium during pregnancy may help to boost how the placenta functions, which has positive effects on the baby’s growth in utero.”

But the researchers warn there are limitations to the work, as the study focused on one bacterial species. Future studies will need to confirm the effects in a more natural, complex microbiome.

The work cannot be automatically translated into human treatments, but will help guide future studies in humans, with the home of creating a relatively simple, low-cost way of improving pregnancy and longer-term outcomes for the mother and her child.

The research was funded by Wellcome and the Biotechnology and Biological Sciences Research Council.