Ofqual has said that A-level students should be allowed more time to find a place through clearing or to re-sit papers.
Speaking at the Headmasters' and Headmistresses' Conference in Liverpool, Kathleen Tattersall, the body's chair, said: "How bad can it be for a student, in the first place to be disappointed by their grades, in the second place to be elated that the appeal has raised their grade and then to find the place has gone?"
She pledged to take the matter up with examining bodies, but called on universities to hold places for those students waiting to hear whether their marks have been revised until the issue is resolved.
"Our remit does not extend to universities but we will do what we can to raise this issue in the appropriate places to protect the interests of the learners," she added.
Every year more than 780,000 A-levels and one million AS-levels are awarded in more than 80 subjects.
Written by Charlotte Michaels