In an e-mail to The Associated Press, the singer's publicist says Beyonce has been advised by her doctors to rest.
She was scheduled to perform at the Sportpaleis in Antwerp.
The show will be rescheduled and tickets can be used at that show.
Her next tour date is on Wednesday at the same arena.
The statement says "she is awaiting word from her doctors before making a decision."
Beyoncé, 31, launched her Mrs Carter World Tour last month in Belgrade, Serbia.
It wraps on 5 August at the Barclays Centre in Brooklyn, New York City.