Deli meat (cold) can be consumed during pregnancy but requires caution. Safe only when heated to steaming. The key guidance from CDC: Heat to 165°F until steaming hot. Potential concerns include: Listeria contamination. These risks are manageable when you follow the recommended limits.
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.