Exam boards analysed more than 2,000 GCSE and A-level papers in the wake of the Manchester attack in May to check for potentially distressing content.
At least two exams had to be changed at short notice after the Ariana Grande concert bombing, reports the Times Educational Supplement.
The boards wanted to ensure questions did not add to pupils' distress, the magazine says.
One Edexcel general studies GCSE paper referred directly to terrorism.
It was changed as it was felt to be "an unnecessary distraction" in the circumstances, Edexcel said.
The other GCSE changed was an AQA religious studies paper.
The bomb attack, as thousands left the Manchester Arena after the concert, came in the middle of the exam season, and the four biggest exam boards had to check the 2,144 papers still to be taken.
AQA also contacted schools about an AS-level French paper that included a reference to Ariana Grande and an A-level French paper that mentioned terrorism in source material, in case they wanted to warn pupils ahead of sitting the exams.
The Manchester attack, coupled with that on London Bridge and the Grenfell Tower fire in west London, all within a month, prompted continued checks on papers during this year's exam season.
Exam boards also told schools directly affected by the Manchester attack that they could decide whether to go ahead with GCSE and A-level exams.
The schedule went ahead as planned but schools could apply for "special consideration" for individual pupils who had to miss them.
"The events of the summer shocked everyone, so we all felt that it was our duty to make sure that our exams didn't add to anyone's distress," said Philip Bridgehouse, customer engagement manager at AQA.
"It was a massive task to review all our exam papers in a short time, but it was a really important thing to do."
Michael Turner, director general of the Joint Council for Qualifications, told the magazine that exam papers "are written nearly a year in advance and changing questions is not something they are going to do lightly".