Table 3 Agreement in preterm, term and post-term classification by last menstrual period (LMP) or Farr examination estimates of gestational age compared to ultrasound estimates
| Â | Ultrasound classification | Agreement statistics | ||||
|---|---|---|---|---|---|---|
LMP classification | Preterm n (%) | Term n (%) | Post-term n (%) | Total n (%) | Crude % agreement | Kappa statistic |
 Preterm | 41 (4.5) | 44 (4.8) | 0 (0.0) | 85 (9.3) | 89.0 | 0.41a |
 Term | 27 (3.0) | 770 (84.4) | 4 (0.4) | 801 (87.8) | ||
 Post-term | 0 (0.0) | 25 (2.7) | 1 (0.1) | 26 (2.6) | ||
 Total | 68 (7.5) | 839 (92.0) | 5 (0.5) | 912 | ||
Farr classification | ||||||
 Preterm | 1 (0.2) | 0 (0.0) | 0 (0.0) | 1 (0.2) | 94.5 | 0.05a |
 Term | 35 (5.1) | 646 (94.3) | 3 (0.4) | 684 (99.9) | ||
 Post-term | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | ||
 Total | 36 (5.3) | 646 (92.3) | 3 (0.4) | 685 | ||