Nigeria's Amaka Ogoegbunam has been provisionally suspended by the IAAF after a positive drugs test at the World Championships in Berlin.
Ogoegbunam's 'A' sample, produced on Tuesday after the 400 metres hurdles semi-final where she was disqualified, was found to contain the banned steroid metenolone.
The athlete, who set a 400m hurdles personal best of 55.80 seconds in the heats, has not requested her 'B' sample to be examined and normal IAAF anti-doping procedures will now be followed.
