Bulgarian teenager Sesil Karatantcheva failed a doping test during this year's French Open, sports daily L'Equipe reported on Tuesday.
Karatantcheva, 16, tested positive for the performance-enhancing steroid nandrolone after she losing to Russia's Elena Likhovtseva in the quarter-finals of the tournament in May.
L'Equipe reported the Bulgarian player attended a hearing held by the International Tennis Federation (ITF) in London last week.
The ITF said they could not "confirm or deny there is a case" for Karatantcheva.
Georgi Donchev, chief secretary of the Bulgarian tennis federation, said they were not aware of any doping case involving one of their athletes.
"We have no such information. As a federation we have not received any official information, neither from the International Tennis Federation, nor from the doping commission," he said. "For the moment, we cannot say anything more."
L'Equipe said Karatantcheva explained during the hearing the high level of nandrolone in her urine sample was because she was pregnant when the test was performed. She said she then had a miscarriage.
A pregnancy test carried out by the French lab of Chatenay Malabry on the player's urine sample was negative," the paper said.