Semifinal
mardi 1 octobre 2019, 19h50 GMT – 19h50 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Shaunae Miller-Uibo | Bahamas | 49.66″ |
| 2 |  Salwa Eid Naser | Bahrain | + 0.13″ |
| 3 |  Wadeline Jonathas | United States | + 0.41″ |
| 4 |  Shericka Jackson | Jamaica | + 0.44″ |
| 5 |  Phyllis Francis | United States | + 0.56″ |
| 6 |  Stephenie McPherson | Jamaica | + 1.04″ |
| 7 | Justyna Swiety-Ersetic | Poland | + 1.3″ |
| 8 |  Iga Baumgart-Witan | Poland | + 1.36″ |
| 9 | Paola Moran | Mexico | + 1.42″ |
| 10 | Sada Williams | Barbados | + 1.65″ |
| 11 |  Lisanne de Witte | Netherlands | + 1.75″ |
| 12 | Roxana Gómez | Cuba | + 1.9″ |
| 13 |  Bendere Oboya | Australia | + 1.92″ |
| 14 | Kendall Ellis | United States | + 1.92″ |
| 15 | Emily Diamond | Great Britain | + 1.96″ |
| 16 | Aliyah Abrams | Guyana | + 2.05″ |
| 17 | Patience Okon | Nigeria | + 2.23″ |
| 18 |  Mary Moraa | Kenya | + 2.45″ |
| 19 |  Déborah Sananes | FFA - France Athlétisme | + 2.58″ |
| 20 |  Lada Vondrova | Czech Republic | + 2.59″ |
| 21 |  Favour Ofili | Nigeria | + 2.92″ |
| 22 |  Laviai Nielsen | Great Britain | + 3.28″ |
| 23 | Shakima Wimbley | United States | + 23.89″ |
 Galefele Moroko | Botswana | DNS |