The 21-year-old "All About That Bass" hitmaker has been forced to scrap a handful of dates, and broke the news to fans on Instagram, reported Billboard.
"I don't want anyone worrying but I have had a haemorrage (sic) on my vocal chords," she posted.
"Right now the doctors want me on complete vocal rest until they are healed, so I have to postpone my first two shows in Atlantic City and Connecticut."
She added, "I love you all very much and want to get healed quickly so I can show you this amazing tour we've been working on. I am truly sorry to everyone who has bought tickets and made travel plans. I hate this."
Trainor is hoping to resume the MTrain Tour in Detroit, Michigan on July 9.
Sam Smith and Hugh Jackman had to scrap a series of live shows and commitments after discovering they had vocal haemorrhages earlier this year.