Heat 1
dimanche 6 août 2017, 12h55 GMT – 12h55 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Allyson Felix | United States | 52.44″ |
| 2 |  Irini Vasiliou | Greece | + 0.17″ |
| 3 |  Ashley Kelly | British Virgin Islands | + 0.26″ |
| 4 |  Maria Benedicta Chigbolu | Italy | + 0.56″ |
| 5 | Maggie Barrie | Sierra Leone | + 0.76″ |
| 6 | Justyna Swiety-Ersetic | Poland | + 1.18″ |
| 7 | Maximila Imali | Kenya | + 1.53″ |
| 8 | Travia Jones | Canada | + 1.58″ |
| 9 | Samantha Dirks | Belize | + 2.3″ |