The sex of a baby is associated with differences in morning sickness, and other symptoms pregnant women generally face. This would be the effects on the expecting mother’s immune system, suggests a new study published in the journal Brain, Behavior, and Immunity.
Women worldwide have reported differences in their reactions to pregnancy based on whether they’ve carried a baby-boy or a baby-girl—claims that several scientific studies have come to support over the years, and the new paper, authored by a team from The Ohio State University Wexner Medical Center, appears to further strengthen this body of research: the sex of a baby is possibly linked with differences in symptoms because of heightened immune responses of the mother.
The team of researchers, led by Amanda Mitchell, analysed data from a group of 80 pregnant women to determine whether foetal sex was linked with different levels of a substance called cytokine (an immune marker). Mitchell and her colleagues examined cytokines in the blood of their participants, and those produced in immune cells left exposed to bacteria in laboratory.
The results show that the pregnant women displayed no difference in blood cytokine levels pertaining to foetal sex. However, the bacteria-exposed immune cells of those expecting female babies had more pro-inflammatory cytokines. Mitchell explains that women carrying female babies exhibit an enhanced inflammatory response when their immune system was triggered by potentially-harmful organisms (the bacteria), as opposed to their counterparts carrying male babies.
Inflammation is not a bad thing per se: the immune system will respond to wounds, illnesses, and entry of viruses and bacteria into the body with the appropriate inflammatory reactions. However, a heightened level of this response (inflammation) will cause stress to the body, resulting in effects like pain and fatigue. This is apparently what might be happening to some women: those pregnant with female foetuses tend to display worse symptoms for certain illnesses, such as asthma, when compared to women carrying male foetuses.
“This research helps women and their obstetricians recognize that fetal sex is one factor that may impact how a woman’s body responds to everyday immune challenges and can lead to further research into how differences in immune function may affect how a women responds to different viruses, infections or chronic health conditions (such as asthma), including whether these responses affect the health of the fetus,” explains Mitchell.
Mitchell does add that more research is needed to understand the apparent link between foetal sex and maternal inflammation. She suggests that placental sex hormones might be playing a role to bring about the heightened level of inflammation.
She also proposes potential ways of tackling the issue by dealing with immune function.
“It’s important to think about supporting healthy immune function, which doesn’t necessarily mean boosting it—it’s problematic to have too little or too great of an immune response. 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. Of course, it’s always important to check with your healthcare provider before making any changes to your routine or diet,” she said.