| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 3654 | Shaunae MILLER-UIBO |  BAH | 50.36 Q | 0.161 | 
| 2 | 4037 | Stephenie Ann MCPHERSON |  JAM | 50.56 Q SB | 0.159 | 
| 3 | 4341 | Quanera HAYES |  USA | 50.71 | 0.191 | 
| 4 | 4097 | Gunta VAIÄŒULE |  LAT | 51.57 | 0.216 | 
| 5 | 3786 | Roxana GÓMEZ |  CUB | 52.01 | 0.251 | 
| 6 | 4201 | Bianca Razor |  ROU | 52.09 | 0.180 | 
| 7 | 4144 | Patience Okon GEORGE |  NGR | 52.60 | 0.189 | 
| 8 | 4021 | Ashley Kelly |  IVB | 54.50 | 0.184 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 3707 | Salwa Eid NASER |  BRN | 50.08 NR | 0.200 | 
| 2 | 4330 | Allyson FELIX |  USA | 50.12 | 0.178 | 
| 3 | 4054 | Novlene Williams-Mills |  JAM | 50.67 | 0.266 | 
| 4 | 4030 | Shericka JACKSON |  JAM | 50.70 | 0.191 | 
| 5 | 3679 | Lydia JELE |  BOT | 51.57 | 0.200 | 
| 6 | 4138 | Yinka AJAYI |  NGR | 52.10 | 0.247 | 
| 7 | 3977 | Eirini VASILEIOU |  GRE | 53.27 | 0.190 | 
| 3996 | Sheoran Nirmla |  IND | DQ | 0.285 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | ms* | Reaction Time | 
|---|---|---|---|---|---|---|
| 1 | 4331 | Phyllis FRANCIS |  USA | 50.37 | 0.187 | |
| 2 | 4027 | Chrisann GORDON-POWELL |  JAM | 50.87 | 0.172 | |
| 3 | 3682 | Amantle MONTSHO |  BOT | 51.28 SB | 0.203 | |
| 4 | 3960 | Ruth Sophia SPELMEYER-PREUß |  GER | 51.77 | 0.164 | |
| 5 | 4165 | Iga BAUMGART-WITAN |  POL | 51.81 | .801 | 0.213 | 
| 6 | 3885 | Zoey CLARK |  GBR | 51.81 PB | .804 | 0.188 | 
| 4140 | Margaret Bamgbose |  NGR | DQ | 0.262 | ||
| 4389 | Kabange Mupopo |  ZAM | DQ | 0.204 | 
ms - Milliseconds - shown when two or more competitors finish with the same time down to hundredths of a second