Table 3.
Random forest variable importance.
| Variables | Variable importance rankings | |
|---|---|---|
| PTB vs. FTB | SPTB vs. FTB | |
| Maternal age | 5 | 3 |
| Pre-pregnancy BMI | 1 | 2 |
| In vitro fertilization | 12 | 9 |
| Prior preterm birth | 14 | 13 |
| Preeclampsia | 3 | 14 |
| Chronic hypertension | 15 | 15 |
| Gestational diabetes mellitus | 10 | 8 |
| PROM | 6 | 1 |
| CAM | 11 | 7 |
| CAM stage | 13 | 5 |
| Periodontitis stage | 7 | 10 |
| MGI | 2 | 6 |
| MGI ≥ 2 | 8 | 11 |
| Plaque index ≥ 2 | 9 | 12 |
| DMFT-index | 4 | 4 |
The ranking of a top-5 predictor is highlighted in Bold.
BMI, body mass index; PROM, prelabor rupture of the membranes; CAM, chorioamnionitis; MGI, modified gingival index; DMFT, decayed, missing, filled teeth; PTB, preterm birth; FTB, full-term birth; SPTB, spontaneous preterm birth.