Parsley (large amounts) can be consumed during pregnancy but requires caution. Culinary amounts safe; avoid medicinal doses. The key guidance from WHO: Use as garnish/seasoning only. Potential concerns include: May stimulate uterus in large amounts. 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.