The singer's publicist said Beyonce has been advised by her doctors to rest.
She was scheduled to perform at the Sportpaleis in Antwerp tongiht (May 14). The show will be rescheduled and tickets can be used at that show.
Her next tour date is on May 15 at the same arena. The statement said "she is awaiting word from her doctors before making a decision."
Beyonce, 31, launched her Mrs Carter World Tour last month in Belgrade, Serbia. It wraps on August 5 at the Barclays Centre in Brooklyn.