Placenta: bacteria provoke premature birth

Placenta: bacteria provoke premature birth

Bacteria in the placenta affect premature births

In the womb, the child is cared for via the placenta. The tissue in the uterus, also known as the mother cake, also filters toxins and germs from the mother's blood. However, as researchers have now found, this organ is not completely germ-free.

Diverse bacterial community lives in the placenta As US researchers reported, a small, diverse bacterial community lives in the placenta of pregnant women, the composition of which most closely resembles that of the oral cavity. In the journal Science Translational Medicine, they write that there is a connection between the type of bacteria and the risk of premature birth. The bacterial composition is changed by infections in pregnancy such as urinary tract infections.

Supply of the embryo via the mother cake The mother cake, as the placenta is also called, forms at the beginning of pregnancy and ensures the supply of the growing embryo with nutrients and oxygen via the umbilical cord. It also serves as a natural barrier between the mother's and the child's bloodstream and prevents certain pollutants and pathogens from reaching the mother from the child. However, the placenta does not filter out all harmful substances from the mother's blood and not all bacteria, as the new study suggests. Various studies had already shown in the past that pesticides in pregnant women and mothers could pose a health risk for the unborn or breastfeeding child, since the poisons are not only deposited in breast milk, but also in the mother cake and are thus transmitted to the child.

Low number of bacteria A total of 320 placentas of women were examined by the scientists around Kjersti Aagaard from the Baylor College of Medicine and Texas Children's Hospital in Houston after the birth. Using genetic engineering methods, they identified the bacterial strains found therein and then compared the composition with that of other body regions. In recent years, data on the diversity of bacteria in and on humans have been collected at the "Human Microbiom Project". The bacterial composition of the placenta differed from woman to woman. In general, the number of bacteria was low, the gut bacteria Escherichia coli was most common in most women. The majority of the bacteria were harmless and belonged to the usual human germs.

Similarities with the bacterial composition in the oral cavity The researchers found that the bacterial composition was similar to that of the oral cavity, especially on the tongue, the tonsils and in dental plaque. The bacteria probably reached the mother cake in the early pregnancy through the mother's blood. Her new study also gives new clues as to when children are first colonized with bacteria, namely possibly already in the womb via the placenta. Certain germs were more common in women who gave birth prematurely and others were less common. In another study, the scientists now want to investigate this connection in more detail. In addition, the composition of the bacterial community also changed in women who had an infection, such as a urinary tract infection, in the first and early second trimester of pregnancy. (sb)

Image: JMG /

Author and source information

Video: Placental abruption - causes, symptoms, diagnosis, treatment, pathology