| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 1684 | Marileidy PAULINO |  DOM | 49.38 Q NR | 0.172 | 
| 2 | 2501 | Candice MCLEOD |  JAM | 49.51 Q PB | 0.162 | 
| 3 | 1583 | Roxana GÓMEZ |  CUB | 49.71 q PB | 0.168 | 
| 4 | 3853 | Quanera HAYES |  USA | 49.81 q | 0.153 | 
| 5 | 1606 | Eleni ARTYMATA |  CYP | 50.80 NR | 0.191 | 
| 6 | 1112 | Susanne GOGL-WALLI |  AUT | 51.52 PB | 0.224 | 
| 7 | 2021 | Ama PIPI |  GBR | 51.59 | 0.140 | 
| 8 | 1629 | Lada VONDROVÁ |  CZE | 51.62 | 0.183 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 1131 | Shaunae MILLER-UIBO |  BAH | 49.60 Q | 0.155 | 
| 2 | 2033 | Jodie WILLIAMS |  GBR | 49.97 Q PB | 0.136 | 
| 3 | 2500 | Roneisha MCGREGOR |  JAM | 50.34 | 0.181 | 
| 4 | 3857 | Wadeline JONATHAS |  USA | 50.51 | 0.189 | 
| 5 | 2924 | Paola MORÁN |  MEX | 51.06 SB | 0.168 | 
| 6 | 2995 | Lieke KLAVER |  NED | 51.37 | 0.208 | 
| 7 | 2249 | Aliyah ABRAMS |  GUY | 51.46 | 0.137 | 
| 8 | 1762 | Aauri Lorena BOKESA |  ESP | 51.57 PB | 0.194 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | 2502 | Stephenie Ann MCPHERSON |  JAM | 49.34 Q PB | 0.134 | 
| 2 | 3847 | Allyson FELIX |  USA | 49.89 Q SB | 0.179 | 
| 3 | 1151 | Sada WILLIAMS |  BAR | 50.11 NR | 0.167 | 
| 4 | 3164 | Natalia KACZMAREK |  POL | 50.79 | 0.165 | 
| 5 | 1388 | Kyra CONSTANTINE |  CAN | 51.22 | 0.177 | 
| 6 | 1920 | Amandine BROSSIER |  FRA | 51.30 | 0.170 | 
| 7 | 3223 | Cátia AZEVEDO |  POR | 51.32 | 0.146 | 
| 8 | 2991 | Lisanne DE WITTE |  NED | 52.09 | 0.178 |