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This chart outlines expected ultrasound measurements (in mm) based on gestational age.
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Get the app!BPD: biparietal diameter (the diameter between the 2 sides of the head
HC: head circumference
AC: abdominal circumference
FL: femur length
Weeks | BPD (mm) | HC (mm) | AC (mm) | FL (mm) |
16 | 32.3 | 124.4 | 99.1 | 20.5 |
16.5 | 34.2 | 131.2 | 105.5 | 22.1 |
17 | 36.0 | 137.9 | 111.9 | 23.7 |
17.5 | 37.7 | 144.5 | 118.2 | 25.2 |
18 | 39.5 | 151.1 | 124.5 | 26.7 |
18.5 | 41.3 | 157.7 | 130.7 | 28.3 |
19 | 43.0 | 164.1 | 136.9 | 29.8 |
19.5 | 44.7 | 170.5 | 143.0 | 31.2 |
20 | 46.4 | 176.8 | 149.1 | 32.7 |
20.5 | 48.1 | 183.0 | 155.1 | 34.1 |
21 | 49.7 | 189.2 | 161.1 | 35.6 |
21.5 | 51.4 | 195.3 | 167.0 | 37.0 |
22 | 53.0 | 201.3 | 172.9 | 38.4 |
22.5 | 54.6 | 207.2 | 178.7 | 39.8 |
23 | 56.2 | 213.0 | 184.5 | 41.1 |
23.5 | 57.8 | 218.7 | 190.2 | 42.5 |
24 | 59.3 | 224.4 | 195.9 | 43.8 |
24.5 | 60.8 | 229.9 | 201.5 | 45.1 |
25 | 62.3 | 235.4 | 207.1 | 46.4 |
25.5 | 63.8 | 240.8 | 212.7 | 47.7 |
26 | 65.3 | 246.0 | 218.1 | 48.9 |
26.5 | 66.7 | 251.2 | 223.6 | 50.2 |
27 | 68.1 | 256.2 | 228.9 | 51.4 |
27.5 | 69.5 | 261.2 | 234.3 | 52.6 |
28 | 70.8 | 266.1 | 239.6 | 53.8 |
28.5 | 72.2 | 270.8 | 244.8 | 55.0 |
29 | 73.5 | 275.5 | 250.0 | 56.1 |
29.5 | 74.7 | 280.0 | 255.1 | 57.3 |
30 | 76.0 | 284.4 | 260.2 | 58.4 |
30.5 | 77.2 | 288.7 | 265.2 | 59.5 |
31 | 78.4 | 292.9 | 270.2 | 60.6 |
31.5 | 79.6 | 297.0 | 275.1 | 61.7 |
32 | 80.7 | 300.9 | 280.0 | 62.7 |
32.5 | 81.9 | 304.7 | 284.8 | 63.8 |
33 | 82.9 | 308.4 | 289.6 | 64.8 |
33.5 | 84.0 | 312.0 | 294.3 | 65.8 |
34 | 85.0 | 315.5 | 299.0 | 66.8 |
34.5 | 86.0 | 318.8 | 303.7 | 67.7 |
35 | 87.0 | 322.0 | 308.2 | 68.7 |
35.5 | 87.9 | 325.0 | 312.8 | 69.6 |
36 | 88.8 | 327.9 | 317.3 | 70.6 |
36.5 | 89.7 | 330.7 | 321.7 | 71.5 |
37 | 90.5 | 333.3 | 326.1 | 72.3 |
37.5 | 91.3 | 335.8 | 330.4 | 73.2 |
38 | 92.1 | 338.2 | 334.7 | 74.1 |
38.5 | 92.8 | 340.4 | 338.9 | 74.9 |
39 | 93.5 | 342.5 | 343.1 | 75.7 |
39.5 | 94.2 | 344.4 | 347.2 | 76.5 |
40 | 94.8 | 346.1 | 351.3 | 77.3 |
40.5 | 95.4 | 347.7 | 355.4 | 78.1 |
41 | 95.9 | 349.2 | 359.3 | 78.8 |
41.5 | 96.5 | 350.5 | 363.3 | 79.5 |
42 | 96.9 | 351.6 | 367.2 | 80.3 |
Hadlock Formulas: Haddlock Radiology 1984; 152: 497-501
Read More:
Your Guide to Ultrasound
Fetal Ultrasound Measurements