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Immune System Activity In Pregnant Women Could Harm Babies' Brains

An expecting mother's immune system can affect her baby's brain development. Pexels

A new study has revealed how a pregnant woman's activated immune system can affect the brain development of her child. Factors such as infections, stress, illness, or allergies can trigger immune system activity. According to the study, if this responsive process takes place during a pregnancy, it can have negative effects on the child’s brain functions.

The study, titled “Maternal immune activation during the third trimester is associated with neonatal functional connectivity of the salience network and fetal to toddler behavior,” was published in the Journal of Neuroscience. The aim was to establish a link between markers of inflammation in the mothers’ blood and changes in nervous system of their babies.

Bradley Peterson, who is the director of the Institute for the Developing Mind in the Department of Pediatrics at Children's Hospital in Los Angeles, led a team of researchers in studying a group of young, expecting mothers between the ages of 14 to 19 years. Given the young age group, the expectant mothers were at a higher risk of psychosocial stress and inflammation.

The participants were recruited during their second trimester, while blood tests and fetal heart monitoring took place during the third trimester. Firstly, the study looked at the relationship between the two proteins released by the mother's immune system during her third trimester. Secondly, it examined children’s brain network, which is involved in psychiatric disorders. 

After the anatomical brain scans of the newborns, the researchers followed up by conducting a cognitive behavioral assessment of the babies when they were 14 months old. They were assessed in terms of motor skills, language development, and behavior.

Results suggested a mother's defensive immune response could influence their child's susceptibility to brain disorders such as autism or schizophrenia later in life. The activation of the maternal immune system was also linked to lower fetal heart rate at the end of gestation. Brain imaging showed high levels of the C-Reactive protein (which is associated with inflammation) as well as significant changes in the brain region known as the salience network.

Peterson explained how the brain is constantly receiving messages from both the body and the external world. The salience network, he said "sifts through that information and decides what is important and warrants action."

His study is the first one to link maternal inflammation directly to disruptions in the salience network in human infants. Earlier, this type of research was conducted with animals where results suggested the proteins released during the immune response could affect offspring.

Peterson explained how these results will help researchers cross a major threshold in understanding the link between the maternal immune system and childhood brain development. 

"This finding fills in a missing piece," he said. "Although studies in animals have suggested it, this study indicates that markers of inflammation in a mom's blood can be associated with short- and long-term changes in their child's brain, which will now allow us to identify ways to prevent those effects and ensure children develop in the healthiest possible way beginning in the womb and continuing through later childhood and beyond."