Microbiota senses pregnancy, helps baby develop.

In a crucial partnership dictating the lifelong habits and health of offspring, pregnancy is accompanied by alterations in the microbiome. Furthermore, the microbiome, bacteria living inside and on our bodies, also aids in digestion and forms part of the immune system. Researchers are aware the pregnancy microbiota is partially responsible for weight gain and essential inflammatory response, however, the mechanisms driving these changes are unknown. 

Now,  a study led by researchers at Bar-Ilan University shows the gut microbiota senses pregnancy and assists the baby in breaking down sugar in the mother’s milk.  The team states progesterone, a hormone known to play a role in the menstrual cycle and in maintaining the early stages of pregnancy, regulates the composition of the gut microbiome during gestation to aid in the development of the baby.  The opensource study is published in the journal Cell Reports.

Pregnancy & the microbiota

Previous studies show pregnancy is accompanied by alterations in the oral, skin, vaginal, and gut microbial profiles. Additionally, progesterone levels also increase dramatically during pregnancy to play a crucial role in regulating and maintaining gestation.

Although some links between the endocrine system and the microbiota have been previously described, understanding of the precise interactions between the endocrine system and the microbiota is still limited.  The current study shows progesterone regulates the microbial composition of bacteria during pregnancy hypothesized to help the baby develop.

The current study follows pregnancy in mice and women to observe an increase in the level of Bifidobacterium in the microbiota.  Results show levels of Bifidobacterium rapidly increased when progesterone is administered in vitro in mice, suggesting Bifidobacterium senses progesterone and then responds to it.  Data findings show a dramatic shift in the gut microbial composition of women and mice during late pregnancy, including an increase in the relative abundance of Bifidobacterium.

The lab explains Bifidobacterium is crucial for infants because they metabolize healthy sugars in breast milk which are important for babies’ growth. Thus, a lack of an increase in Bifidobacterium during pregnancy linked to preterm delivery. 

Hormones regulate the microbiota

They go on to add these discoveries provide new insights into understanding the correlation between hormones and intestinal bacteria during pregnancy, and other conditions in which hormones are involved. These include fertility treatments or therapy in menopausal women.

The team surmises they demonstrate progesterone modulates pregnancy-associated gut microbial composition, including an increase in the relative abundance of Bifidobacterium.  For the future, the researchers state they plan to identify how the Bifidobacterium bacteria react, what genes are turned on, what other pregnancy hormones do, and what effect they have.

Source: Bar-Ilan University

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