Table 2. Characteristics at time of booking for women who gave birth at term, preterm, early preterm and late preterm.
| Study Characteristic | Characteristic subcategory | Term Birth (37–41 wks) (n = 1729) | Preterm (24–36 wks) vs. Term (n = 351) | p-value | Early Preterm (24–33 wks) vs. Term (n = 87) | p-value | Late Preterm (34–36 wks) vs. Term (n = 264) | p-value |
| Age | (mean, SD, years) | 23.02 +/− 5.08 | 22.8 +/− 5.69 | 0.55 | 22.92 +/− 5.87 | 0.88 | 22.8 +/− 5.65 | 0.54 |
| <20 (%) | 27.9 | 33.6 | 0.03 | 37.2 | 0.07 | 32.5 | 0.13 | |
| Parity | Primiparous (parity 0) (%) | 35.8 | 39.8 | 0.18 | 39.7 | 0.48 | 39.8 | 0.23 |
| BMI | (mean, SD) | 22.8 +/− 2.6 | 22.3 +/− 2.5 | 0.006 | 22.3 +/− 2.7 | 0.15 | 22.3 +/− 2.4 | 0.02 |
| BMI <18.5 (%) | 3.2 | 4.8 | 0.09 | 9.3 | 0.005 | 3.8 | 0.64 | |
| Previous pregnancy outcome a | Previous preterm birth (%) | 6.1 | 13.2 | 0.001 | 19.1 | 0.001 | 11.3 | 0.02 |
| Previous stillbirth (%) | 5.0 | 7.6 | 0.14 | 14.9 | 0. 003 | 5.3 | 0.87 | |
| Previous neonatal death (%) | 4.1 | 8.1 | 0.02 | 8.5 | 0.15 | 8.0 | 0.03 |
a
Excludes primiparous women.