Scientists have found a dramatic change in the composition of bacteria in late pregnancy, including an increase in the relative abundance of bifidobacteria. These bacteria are critical to babies as they metabolize the beneficial sugars in breast milk, which are important for the development of the newborn.
Researchers at Bar-Ilan University (Israel) found that gut bacteria “sense” pregnancy and “understand” the need to move to the next generation to help babies break down sugar in breast milk. The fact is that pregnancy is accompanied by changes in the microbiome: the set of bacteria that live in our body is about two kilograms of the body and is important for health and the fight against diseases. Previous research on changes in the microbiome has shown that it is partially responsible for weight gain and a significant inflammatory response during pregnancy. However, the mechanisms governing these changes were unknown.
A new study by Dr. Omry Koren and Professor Yoram Louzon has shown that progesterone regulates the microbial makeup of bacteria during pregnancy to help a baby develop. The results of the scientists' work are published in the journal Cell Reports.
Experts studied changes in bacteria as pregnancy progressed and found dramatic changes in the composition of bacteria in late pregnancy, including an increase in the relative abundance of bifidobacteria. These bacteria are critical for babies because they metabolize the beneficial sugars in breast milk, which are important for development, and also contain probiotic potential. Previous studies have shown that the lack of an increase in the number of bifidobacteria during pregnancy correlates with preterm birth.
During the experiments, scientists discovered a sharp change in the composition of bacteria in late pregnancy, including an increase in the relative number of bifidobacteria / © Cell Reports
A group of researchers led by Koren found that pregnant women experience an increase in progesterone levels, accompanied by an increase in the inflammatory response. They also recorded an increase in the number of other bacteria, but bifidobacteria were the only group that was identical to pregnancy in mice: when scientists simulated pregnancy in mice using progesterone, they again found that bifidobacteria increased. This led to the conclusion that they somehow sense and respond to the presence of progesterone. When the researchers injected progesterone in vitro, they again found that bifidobacteria were rapidly increasing in numbers, supporting the idea that this group of bacteria senses and responds to progesterone.
“Our results outline a model in which progesterone promotes bifidobacterial growth during late pregnancy. The findings provide new insights into the relationship not only between hormones and gut bacteria during pregnancy, but also for other conditions in which hormones are involved, such as progesterone supplementation as a component of fertility treatment or therapy for menopausal women,”says Koren.