Measure | Ultrasound | LMP (n = 912) | Farr examination (n = 685) |
---|---|---|---|
Median GA (days) (Interquartile range) | 273.9 (268.2, 279.3) | 276.0a (268.0, 282.0) | 286.7a (286.7, 288.6) |
Mean difference (days) (95% CI) | Reference | 1.4 (0.7, 2.0) | 12.9 (12.2, 13.5) |
Intra-class correlation coefficient (95% CI) | Reference | 0.78 (0.74, 0.80) | 0.26 (0.15, 0.37) |
Concordance correlation coefficient (95% CI) | Reference | 0.63 (0.59, 0.67) | 0.05 (0.04, 0.07) |
Agreement with ultrasound n (%) | |||
 ±7 days | Reference | 625 (68.5) | 166 (24.2) |
 ±10 days | Reference | 731 (80.2) | 254 (37.1) |
 ±14 days | Reference | 806 (88.4) | 382 (55.8) |