Serena Williams was given "emergency treatment" Monday for a hematoma related to a blood clot in her lungs, says People magazine. Doctors who were treating Williams' injured foot discovered the embolism in her lungs last week, her spokeswoman told the magazine.
Williams is reportedly receiving treatment at Cedars-Sinai Medical Center in Los Angeles, where "doctors are continuing to monitor her situation closely to avoid additional complications," according to spokeswoman Nicole Chabot.
The pulmonary embolism was diagnosed after Williams went to Los Angeles for treatment. The tennis star has fought through injuries to her feet and knees in recent years; she hasn't competed in a tournament since she won her fourth Wimbledon title last July.
Despite her condition, Williams still attended Oscars parties thrown by Elton John and Vanity Fair Sunday night.