New research out of Ohio State seems to prove the old wives’ tale that pregnant women carrying girls feel worse than pregnant women carrying boys. In my case, that old wives’ tale turned out to be true. I felt great with my son’s pregnancy, horrible with my daughter’s.

Why might that be true?

A study from Amanda Mitchell, a postdoctoral researcher in the Institute for Behavioral Medicine Research at Ohio State’s Wexner Medical Center, which was published in the February issue of the journal Brain, Behavior, and Immunity, found that pregnant women carrying girls had a higher level of immune markers called cytokines in their immune cells.

“This means that women carrying female fetuses exhibited a heightened inflammatory response when their immune system was challenged, compared to women carrying male fetuses,” Mitchell explained in a press release.

This could be why women carrying girl babies experience more symptoms with conditions like asthma than women carrying boy babies.

A lot more research needs to be done, but Mitchell says, “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.”