| Rank* | County | Percent of Babies that were Preterm Births | County/State Ratio | County/US Ratio |
|---|---|---|---|---|
| 1 | Oconee County | 11.0 | 0.81 | 0.95 |
| 2 | Beaufort County | 11.0 | 0.81 | 0.95 |
| 3 | Anderson County | 11.6 | 0.85 | 0.99 |
| 4 | Abbeville County | 12.1 | 0.89 | 1.04 |
| 4 | Colleton County | 12.1 | 0.89 | 1.04 |
| 6 | Lexington County | 12.1 | 0.89 | 1.04 |
| 7 | York County | 12.2 | 0.90 | 1.05 |
| 8 | Aiken County | 12.3 | 0.90 | 1.05 |
| 9 | Jasper County | 12.4 | 0.91 | 1.06 |
| 10 | Saluda County | 12.5 | 0.92 | 1.07 |
| 11 | Pickens County | 12.5 | 0.92 | 1.08 |
| 12 | Berkeley County | 12.6 | 0.93 | 1.09 |
| 13 | Greenville County | 12.7 | 0.94 | 1.09 |
| 14 | Calhoun County | 12.8 | 0.94 | 1.10 |
| 15 | Dorchester County | 13.2 | 0.97 | 1.14 |
| 16 | Hampton County | 13.3 | 0.98 | 1.14 |
| 17 | Florence County | 13.4 | 0.99 | 1.15 |
| 18 | Sumter County | 13.5 | 0.99 | 1.16 |
| 19 | Charleston County | 13.6 | 1.00 | 1.17 |
| 19 | Edgefield County | 13.6 | 1.00 | 1.17 |
| 21 | Horry County | 13.7 | 1.01 | 1.18 |
| 22 | Georgetown County | 13.8 | 1.02 | 1.19 |
| 23 | Allendale County | 14.0 | 1.03 | 1.21 |
| 24 | Chester County | 14.2 | 1.05 | 1.22 |
| 25 | Darlington County | 14.5 | 1.07 | 1.25 |
| 26 | Laurens County | 14.5 | 1.07 | 1.25 |
| 27 | Kershaw County | 14.8 | 1.09 | 1.27 |
| 28 | Spartanburg County | 14.8 | 1.09 | 1.27 |
| 29 | Greenwood County | 15.0 | 1.10 | 1.29 |
| 30 | Richland County | 15.0 | 1.10 | 1.29 |
| 31 | Williamsburg County | 15.2 | 1.12 | 1.30 |
| 32 | Barnwell County | 15.3 | 1.12 | 1.31 |
| 33 | Newberry County | 15.6 | 1.15 | 1.34 |
| 34 | Lancaster County | 15.8 | 1.16 | 1.36 |
| 35 | McCormick County | 16.0 | 1.18 | 1.38 |
| 36 | Union County | 16.4 | 1.20 | 1.41 |
| 37 | Orangeburg County | 16.4 | 1.21 | 1.41 |
| 38 | Dillon County | 16.6 | 1.22 | 1.43 |
| 39 | Fairfield County | 16.9 | 1.25 | 1.46 |
| 40 | Lee County | 17.1 | 1.26 | 1.47 |
| 41 | Chesterfield County | 17.2 | 1.26 | 1.48 |
| 42 | Cherokee County | 17.2 | 1.27 | 1.48 |
| 43 | Marion County | 17.2 | 1.27 | 1.48 |
| 44 | Bamberg County | 18.6 | 1.37 | 1.60 |
| 45 | Clarendon County | 18.9 | 1.39 | 1.63 |
| 46 | Marlboro County | 19.9 | 1.46 | 1.71 |
* 1 is best, 46 is worst.