Unlike ground beef, whole cuts of steak are safe at medium (145°F with 3-minute rest) because bacteria is on the surface and gets killed by heat. However, many doctors recommend well-done to eliminate all risk. Avoid rare or blue-rare steak during pregnancy.
A "Use Caution" rating means this food is generally fine during pregnancy but comes with a specific factor worth managing — a daily limit, a preparation requirement, or a moderation guideline — rather than a reason to avoid it outright. These ratings reflect general guidance from the FDA, ACOG, CDC, and USDA. The goal of the "caution" label is to flag what to pay attention to, not to suggest the food is unsafe when that factor is properly managed.