There’s a long list of “don’ts” when you get pregnant: don’t drink, don’t eat lunch meat cold, don’t have too much coffee or take many over the counter medicines.

Now, it looks like we can add “don’t use household appliances.”  A new study is linking them to an increased risk in newborn asthma.

Via Time:

Exposure to electromagnetic fields has been linked to a number of health problems, including cancer and immune system and reproductive abnormalities, and now the latest research adds another concern to the list: childhood asthma.

In the first study of its kind, scientists strapped magnetic field monitors on pregnant women to determine their level of exposure, and studied whether it was associated with the risk of asthma in their children. They found that children born to women with the highest levels of exposure to electromagnetic fields (EMF) — including from microwaves, hair dryers and power lines — had a more than three-fold higher rate of asthma compared to those whose moms had the lowest exposure.

Of course, now women are going to have to find another way to heat up their lunch meat.