Listeria a common food-borne bacterium may pose a greater risk of miscarriage in the early stages of pregnancy than previously thought says a study. For many years listeria has been associated with adverse outcomes in pregnancy but particularly at the end of pregnancy said one of the researchers Ted Golos Professor at University of Wisconsin-Madison in the US. What wasn't known with much clarity before this study is that it appears it's a severe risk factor in early pregnancy Golos said. Pregnant women are warned to avoid many of the foods -- among them unpasteurised milk and soft cheese raw