Researchers from The Ohio State University in the US followed 80 pregnant women across the course of their pregnancy and examined whether women exhibited different levels of immune markers called cytokines based on foetal sex.
Analyses were conducted on levels of cytokines in the blood and levels produced by a sample of immune cells that were exposed to bacteria in the lab.
"While women didn't exhibit differences in blood cytokine levels based on foetal sex, we did find that the immune cells of women carrying female foetuses produced more pro-inflammatory cytokines when exposed to bacteria," said Amanda Mitchell, a postdoctoral researcher at Ohio State University in the US.
Inflammation is a critical part of the immune response involved in wound healing and responses to viruses, bacteria and chronic illnesses.
More From This Section
However, excessive inflammation is stressful to the body and can contribute to sickness-related symptoms, such as achiness and fatigue.
While more research is needed, the heightened inflammation observed among women carrying female foetuses could play a role in why women tend to experience exacerbated symptoms of some medical conditions, including asthma, when carrying a female versus a male foetus.
While maternal inflammation can affect outcomes related to the foetus, like timing of birth, more research is necessary to understand how foetal sex is associated with maternal inflammation.
It is possible the sex hormones or other hormones in the placenta affect maternal inflammation levels, Mitchell said.
"That being said, research has shown that exercise supports healthy immune functioning, as does eating some foods, like leafy greens, and relaxing with activities like meditation," she said.
The study was published in the journal Brain, Behaviour and Immunity.