The U.S. Food and Drug Administration urges pregnant women to avoid soft cheeses that are made from unpasteurized milk, which includes blue cheese and other "blue-veined" cheeses like gorgonzola. Feta, brie, Camembert, queso fresco, queso blanco and panela are listed as similar cheeses to avoid.
According to the FDA, pregnant women should avoid soft cheeses due to the risk of listeria infection. Listeria infection, medically known as listeriosis, is particularly dangerous to pregnant women and infants. The disease is caused by the bacterium Listeria monocytogenes. While many foods contain some presence of potentially harmful microbes, they generally do not occur in dangerous concentrations. Listeria monocytogenes is unique because it rapidly reproduces and reaches harmful concentrations at refrigerator temperatures.
The Centers for Disease Control reports that 1,600 listeria infections occur each year in the United States. Untreated, listeria infection is deadly and results in 260 deaths annually. Infections during pregnancy are harmful to the fetus and may result in stillbirth, miscarriage or premature labor. The infection is easily passed to newborns. Those who experience symptoms of listeria infection, which include fever, muscle aches, fatigue and gastrointestinal upset, after ingesting potentially contaminated food need to seek medical attention immediately. Even with prompt treatment, the CDC explains that the infection can be fatal.