Stillbirth. Our biggest concern is that listeria infection in the expectant woman can cause death of her fetus. There have been cases traced to eating contaminated cheese and cold cuts. Please see my guide on what food to feed your family (and fetus); there are two answers and links to food safety there.
Birth complications. Listeria monocytogenes is a bacteria that can cause serious complications in pregnant women. It can lead to infection of the amniotic fluid, premature labor, miscarriage, or stillbirth. Newborns who acquire listeria can also develop meningitis or sepsis.