Some oily fish varieties are good food choices unless you're pregnant.
The Food and Drug Administration is reminding pregnant women to stay away from certain fish that can be high in mercury.
But the agency won't require package labeling on mercury content, which is what consumer groups had sought.
Consumer groups had long sought the labeling, saying that government guidelines are hard for pregnant women to remember.
The move is unlikely to clear up confusion over exactly what seafood pregnant women should eat or stay away from.
The FDA says the update to its 2004 advice is an attempt to get pregnant women to eat more fish, since many types of low-mercury seafood are good sources of omega-3 fatty acids important for brain development.