How a baby’s sex may play a role in pregnant women’s immunity

Evidence shows that the sex of a baby is associated with pregnant women’s immune responses.

Research shows that a baby’s sex could play a role in why some women report differences with morning sickness, cravings and other symptoms.


Researchers at the Ohio State University Wexner Medical Center followed 80 pregnant women during the courses of their pregnancies, and examined whether the women showed different levels of Cytokines, immune markers, based on fetal sex.

It was found that, while the women did not exhibit differences in blood Cytokine levels based on fetal sex, the female fetuses produced more pro-inflammatory Cytokines when exposed to bacteria.

Different inflammatory response

«This means that women carrying female fetuses showed a heightened inflammatory response when their immune system was challenged» said Amanda Mitchell, a postdoctoral researcher.

Inflammation is a critical part of the immune response involved in wound healing and responses to viruses, bacteria and chronic illnesses. However, excessive inflammation is stressful to the body and can cause achiness and fatigue.


This heightened inflammation in women carrying female fetuses could explain why women tend to experience exacerbated symptoms of some medical conditions, including asthma.

More research is needed to understand just how fetal sex is associated with maternal inflammation.

A balanced immune function is the key factor. Having too little or too great an immune response is problematic.