When I was growing up, my grandma always told me, "Worrying will make you sick," and according to new research, worrying can also make someone else sick. There seems to be a connection between a stressed-out mom, her growing baby, and the baby's developing immune system. It turns out that stress during pregnancy could make a fetus more susceptible to certain substances, which could potentially trigger asthma and allergies down the road.
Harvard Medical School tested this theory by taking blood samples from the umbilical cords of 373 infants. They measured the level of Immunoglobulin (IgE), a chemical found in the blood that's linked to allergies, and found higher levels of IgE in babies with stressed-out mothers. That means that those moms who were worried about money, relationships, or their jobs while pregnant could have influenced the baby's developing immune system.
Of course, more research needs to be done to test other factors besides stress that could affect a baby's risk for future asthma and allergies. It's definitely an interesting concept though and proves how important it is for a pregnant woman to be healthy and happy, both physically and emotionally.