| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 142 | Shaunae MILLER-UIBO |  BAH | 50.12 Q | 0.167 | 
| 2 | 509 | Christine Day |  JAM | 50.82 Q | 0.216 | 
| 3 | 489 | Libania Grenot |  ITA | 51.14 | 0.175 | 
| 4 | 366 | Floria GUEI |  FRA | 51.30 | 0.188 | 
| 5 | 889 | Natasha Hastings |  USA | 51.33 | 0.154 | 
| 6 | 725 | Nadezhda Kotlyarova |  RUS | 51.86 | 0.184 | 
| 7 | 112 | Anneliese RUBIE-RENSHAW |  AUS | 52.04 | 0.180 | 
| 578 | Joy Nakhumicha Sakari |  KEN | DQ | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 390 | Christine Ohuruogu |  GBR | 50.16 Q SB | 0.170 | 
| 2 | 515 | Stephenie Ann MCPHERSON |  JAM | 50.32 Q SB | 0.135 | 
| 3 | 881 | Phyllis FRANCIS |  USA | 50.50 q SB | 0.189 | 
| 4 | 630 | Patience Okon GEORGE |  NGR | 50.76 PB | 0.252 | 
| 5 | 367 | Marie Gayot |  FRA | 50.97 PB | 0.213 | 
| 6 | 736 | Ekaterina Renzhina |  RUS | 51.49 PB | 0.158 | 
| 7 | 678 | Patrycja WYCISZKIEWICZ-ZAWADZKA |  POL | 51.94 | 0.153 | 
| 8 | 205 | Carline Muir |  CAN | 52.31 | 0.228 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 879 | Allyson FELIX |  USA | 49.89 Q SB | 0.154 | 
| 2 | 512 | Shericka JACKSON |  JAM | 50.03 Q PB | 0.187 | 
| 3 | 513 | Novlene Williams-Mills |  JAM | 50.47 q SB | 0.204 | 
| 4 | 843 | Nataliia Pygyda |  UKR | 50.62 PB | 0.176 | 
| 5 | 389 | Anyika Onuora |  GBR | 50.87 PB | 0.175 | 
| 6 | 698 | Bianca Razor |  ROU | 51.05 | 0.167 | 
| 7 | 571 | Maureen Jelagat Maiyo |  KEN | 51.92 | 0.182 | 
| 8 | 944 | Kabange Mupopo |  ZAM | 51.93 | 0.178 |