Career
Yefremova received a two-year ban in 2012 for using testosterone at the 2011 World Athletics Championships. She reached the semi-final at the 2000 World Junior Championships, the 2003 World Championships and the 2004 Olympic Games, and competed at the 2003 World Indoor Championships, the 2005 World Championships, the 2008 Olympic Games and the 2010 World Indoor Championships without progressing from the first round. She also competed at the 2003 World Championships, the 2004 Olympic Games, the 2007 World Championships, and the 2009 World Championships.
In 2011, she competed for Fenerbahçe Athletics in Turkey.
She failed a random drug test in June 2012 and was banned for two years.