Table 2 Levels of precision obtained with a sample size of 100 women for some biometrical fetal parameters (values and half widths in mm)
Abdominal circumference | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Week | Mean | 10% Centile | 5% Centile | CV | %SE_50 | %SE_10 | %SE_5 | Width_50 | Width_10 | Width_5 |
20 | 147.7 | 133.5 | 128.8 | 7.9 | 0.79 | 1.07 | 1.21 | 2.33 | 2.85 | 3.12 |
24 | 190.7 | 173.8 | 166.6 | 7.4 | 0.74 | 1.00 | 1.14 | 2.82 | 3.47 | 3.78 |
28 | 235.2 | 215.4 | 210.6 | 6.4 | 0.64 | 0.86 | 0.98 | 3.01 | 3.72 | 4.13 |
32 | 278.6 | 255.8 | 248.3 | 6.5 | 0.65 | 0.88 | 1.00 | 3.62 | 4.49 | 4.95 |
36 | 314.5 | 288.0 | 277.9 | 7.1 | 0.71 | 0.96 | 1.09 | 4.47 | 5.52 | 6.05 |
Biparietal diameter | ||||||||||
Week | Mean | 10% Centile | 5% Centile | CV | %SE_50 | %SE_10 | %SE_5 | Width_50 | Width_10 | Width_5 |
20 | 46.7 | 44.0 | 42.0 | 5.6 | 0.56 | 0.76 | 0.86 | 0.52 | 0.67 | 0.72 |
24 | 59.0 | 56.0 | 55.0 | 4.8 | 0.48 | 0.65 | 0.74 | 0.57 | 0.73 | 0.81 |
28 | 70.8 | 68.0 | 67.0 | 3.9 | 0.39 | 0.53 | 0.60 | 0.55 | 0.72 | 0.80 |
32 | 80.1 | 77.0 | 75.0 | 3.7 | 0.37 | 0.50 | 0.57 | 0.59 | 0.77 | 0.85 |
36 | 87.1 | 83.0 | 81.0 | 3.7 | 0.37 | 0.50 | 0.57 | 0.64 | 0.83 | 0.92 |
Head circumference | ||||||||||
Week | Mean | 10% Centile | 5% Centile | CV | %SE_50 | %SE_10 | %SE_5 | Width_50 | Width_10 | Width_5 |
20 | 177.4 | 164.4 | 161.2 | 5.8 | 0.58 | 0.78 | 0.89 | 2.06 | 2.57 | 2.87 |
24 | 225.0 | 212.3 | 209.2 | 4.9 | 0.49 | 0.66 | 0.75 | 2.21 | 2.81 | 3.14 |
28 | 269.4 | 254.9 | 251.8 | 4.3 | 0.43 | 0.58 | 0.66 | 2.32 | 2.96 | 3.32 |
32 | 302.8 | 286.9 | 281.6 | 4.1 | 0.41 | 0.55 | 0.63 | 2.48 | 3.17 | 3.54 |
36 | 325.1 | 308.1 | 300.1 | 4.1 | 0.41 | 0.55 | 0.63 | 2.67 | 3.41 | 3.77 |
Femur length | ||||||||||
Week | Mean | 10% Centile | 5% Centile | CV | %SE_50 | %SE_10 | %SE_5 | Width_50 | Width_10 | Width_5 |
20 | 32.6 | 30.0 | 29.0 | 6.9 | 0.69 | 0.93 | 1.06 | 0.45 | 0.56 | 0.61 |
24 | 43.2 | 41.0 | 40.0 | 4.7 | 0.47 | 0.63 | 0.72 | 0.41 | 0.52 | 0.58 |
28 | 53.0 | 51.0 | 50.0 | 3.7 | 0.37 | 0.50 | 0.57 | 0.39 | 0.51 | 0.57 |
32 | 61.9 | 59.0 | 58.0 | 3.3 | 0.33 | 0.45 | 0.51 | 0.41 | 0.53 | 0.59 |
36 | 69.3 | 67.0 | 65.0 | 3.2 | 0.32 | 0.43 | 0.49 | 0.44 | 0.58 | 0.64 |
Humerus length | ||||||||||
Week | Mean | 10% Centile | 5% Centile | CV | %SE_50 | %SE_10 | %SE_5 | Width_50 | Width_10 | Width_5 |
20 | 31.4 | 28.0 | 27.0 | 8.9 | 0.89 | 1.20 | 1.37 | 0.56 | 0.67 | 0.74 |
24 | 40.7 | 38.0 | 37.0 | 6.8 | 0.68 | 0.92 | 1.04 | 0.55 | 0.70 | 0.77 |
28 | 48.6 | 45.0 | 44.0 | 6.3 | 0.63 | 0.85 | 0.97 | 0.61 | 0.77 | 0.85 |
32 | 55.7 | 52.0 | 51.0 | 5.7 | 0.57 | 0.77 | 0.87 | 0.63 | 0.80 | 0.89 |
36 | 61.2 | 57.0 | 56.0 | 5.4 | 0.54 | 0.73 | 0.83 | 0.66 | 0.83 | 0.93 |