As long as it's fully cooked, you're free to eat crab during pregnancy.
When it comes to seafood, it’s best to prepare it yourself or consume it freshly made at a restaurant as opposed to purchasing precooked crab that hasn’t been packaged and sealed (unless you plan on reheating it). This is because you don’t want foods reaching the danger zone, which is between 40 to 140 degrees Fahrenheit. When foods are sitting in this zone, especially for longer periods of time, there’s a greater risk of bad bacteria growing on them. Since you don’t necessarily know for sure that the pre-cooked seafood you get from your local grocery store or seafood market was prepared following all food safety guidelines, it’s safest to do it yourself.