back now with the olympic star who just made history american sprinter and new mom allyson felix shattering usain bolt's record less than a year after having a difficult, premature birth. here is catie beck >> reporter: sprinting to another victory on the world stage. >> i'm just grateful to be healthy and to be working my way back. >> and allyson felix has another world championship. >> reporter: with the win in the mix gender 4x4 relay felix passes running legend usain bolt for the most golds. but this is her first as a mother >> it was really special it's been a crazy year for me. >> reporter: last november, felix had a baby girl but after an emergency c-section, her daughter cameron spent nearly a month in the nicu. it was a turbulent time for the star athlete, negotiating with a sponsorship renewal with nike, requesting protections against punishment for not meeting