Sex of fetus influences mother’s immune state

It is an old wives’ tale that being pregnant with a boy is different than being pregnant with a girl. If a woman is pregnant with a girl, it is rumored she will have a wider stomach, more nausea and overall worse pregnancy symptoms due to a higher level of hormones.

Researchers are now finding that cravings might not be the only thing affected by the sex of a pregnant woman’s child. There is now evidence to prove that the sex of a child can also contribute to a woman’s immune response.

A study conducted by the Ohio State University Wexner Medical Center showed that while a woman’s baseline immune state remained the same, when prompted by a bacteria or infection, it would react differently.

Cytokine, a small protein that plays a vital role in immune response, dictates cell to cell communication during an immune response and can therefore direct cell movement to sites of inflammation. Women carrying a female fetus showed greater secretion of certain cytokines that promote inflammation.

In this specific study, Principal Investigator Amanda Mitchell studied 80 women throughout their pregnancies, testing their levels of cytokines and sex hormones.

Scientists tested the women’s blood both before and after it was exposed to bacteria and found more pro-inflammatory cytokines in women with female fetuses. This may explain some of the symptoms currently attributed to women pregnant with females, such as a higher risk of asthmatic symptoms and other allergic reactions.

One woman, Melissa Fox, found that when she was pregnant with her second child, her first daughter, her pregnancy experience was wildly different. One of the most prominent symptoms of her second pregnancy was the return of her allergies, which she had outgrown when she was younger.

“When I was pregnant with Wren [her daughter], it seemed like [my allergies] were kicking up and flaring up again to where I was having to take something on a daily basis,” Fox said in a press release.

The symptoms Fox had are related to the increase in pro-inflammatory cytokines in her system, promoting swelling and inflammation of her eyes, airways and nose.

Pregnant women are often put into a category of people with weaker immune systems who must be taken special care of. According to a study by Dr. Gil Mor of Yale University, the immune system of a pregnant woman is generally viewed as weaker than if the woman was not pregnant.

While a woman’s immune response may be different to certain diseases during her pregnancy, her immune system itself remains largely the same. The processes that occur during pregnancy simply make the process of the immune system much more complex, so once the system is challenged, differences occur.

More research into this field is needed for two reasons: First to determine exactly what this differing response means for pregnant women and how their prenatal treatment may need to change and, second, to understand the exact reasoning for this relationship. Knowing which hormones play a role in this relationship is necessary to understand how exactly to control the inflammatory response in pregnant women.

For example, knowing the reason for these responses may make cases like Fox’s preventable, allowing her to take medications to mediate her inflammatory cytokines.

The first step to explaining this problem further is to do testing into the responses of the immune systems of pregnant women to specific diseases and observe the immune response. That way, preventative steps can be taken to increase prenatal care and maternal health.