Semifinal
mercredi 2 octobre 2019, 20h05 GMT – 20h05 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Sydney McLaughlin | United States | 53.81″ |
| 2 |  Dalilah Muhammad | United States | + 0.1″ |
| 3 | Rushell Clayton | Jamaica | + 0.36″ |
| 4 |  Sage Watson | Canada | + 0.51″ |
| 5 | Zuzana Hejnová | Czech Republic | + 0.6″ |
| 6 | Ashley Spencer | United States | + 0.61″ |
| 7 | Anna Ryzhykova | Ukraine | + 0.64″ |
| 8 | Lea Sprunger | Switzerland | + 0.71″ |
| 9 |  Zurian Hechavarria | Cuba | + 1.22″ |
| 10 | Amalie Iuel | Norway | + 1.22″ |
| 11 | Shiann Salmon | Jamaica | + 1.35″ |
| 12 |  Hanne Claes | Belgium | + 1.44″ |
| 13 |  Ayomide Folorunso | Italy | + 1.55″ |
| 14 |  Joanna Linkiewicz | Poland | + 1.57″ |
| 15 | Yadisleidis Pedroso | Italy | + 1.59″ |
| 16 |  Sarah Carli | Australia | + 1.62″ |
| 17 | Aminat Yusuf Jamal | Bahrain | + 1.73″ |
| 18 | Vera Rudakova | Authorised Neutral Athlete | + 1.76″ |
| 19 | Gianna Woodruff | Panama | + 1.8″ |
| 20 | Jessica Turner | Great Britain | + 2.06″ |
| 21 | Lauren Wells | Australia | + 2.13″ |
| 22 | Femke Bol | Netherlands | + 2.56″ |
| 23 |  Carolina Krafzik | Germany | + 2.6″ |
| 24 | Meghan Beesley | Great Britain | + 3.08″ |