It is generally advised that pregnant women should not eat raw prosciutto because it is a cured but uncooked meat that can carry harmful bacteria such as Listeria and parasites like Toxoplasma gondii. These infections can pose serious risks to the developing baby, including brain damage and other complications. However, prosciutto can be safe to eat during pregnancy if it is fully cooked to at least 165°F (74°C) before consumption. Cooking prosciutto until steaming, such as baking or pan-frying it, eliminates the risk of these harmful bacteria and makes it safe for pregnant women to eat.
So the recommendation is to avoid raw prosciutto during pregnancy but cooked prosciutto is fine if properly heated.