negative regulation of mRNA modification
Any process that decreases the rate, frequency, or extent of the covalent alteration of one or more nucleotides within an mRNA molecule to produce an mRNA molecule with a sequence that differs from that coded genetically.
GO:0090365
regulation of mRNA modification
is_a
GO:1903312
negative regulation of mRNA metabolic process
is_a
GO:0016556
mRNA modification
negatively_regulates