Prenatal mercury exposure, maternal seafood consumption and associations with child language at five years.

•Maternal blood Hg concentration is low in MoBa.•No associations between maternal blood Hg and symptoms of language impairment.•Prenatal dietary Hg exposure was associated with improved language scores.•Maternal seafood intake were associated with improved language scores.•In sibling analysis, dietary Hg exposure was associated with language impairment.