Table 5: Mean differences in gestational ages derived from The Monash Chart compared to those predicted by the six existing reference charts.
Mean differences in days (95% CI)
Comparison with gestation determined using The Monash Chart
ASUM
2938*
1.8 (1.7 to 1.9)
Hadlock
3052
0.87 (0.81 to 0.93)
Daya
3052
−0.80 (−0.84 to −0.77)
Verburg
641*
−1.80 (−2.0 to −1.6)
Old ASUM
2997*
0.23 (0.20 to 0.27)
Robinson
1476*
−0.16 (−0.27 to −0.05)
*n values are less than 3052 because exact dates were not given for a number of CRL lengths in these charts. Verburg et al. [9], for instance, only provide exact dates for CRL lengths at 5, 10, and 15 mm.