Table 4.
HC reference values for boys and girls from 12 to 40 weeks
| GA | Boys (HC) | Girls (HC) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| C5 | C10 | C50 | C90 | C95 | C5 | C10 | C50 | C90 | C95 | |
| 12 | 61.3 | 63.3 | 70.3 | 77.4 | 79.4 | 61.9 | 63.6 | 69.7 | 76.1 | 78.1 |
| 13 | 74.4 | 76.5 | 83.8 | 91.1 | 93.2 | 74.3 | 76.1 | 82.6 | 89.5 | 91.6 |
| 14 | 88.2 | 90.3 | 97.8 | 105.3 | 107.5 | 87.3 | 89.2 | 96.1 | 103.3 | 105.4 |
| 15 | 101.9 | 104.1 | 111.6 | 119.2 | 121.4 | 100.6 | 102.6 | 109.6 | 117.0 | 119.2 |
| 16 | 115.2 | 117.4 | 124.9 | 132.6 | 134.8 | 113.6 | 115.6 | 122.8 | 130.4 | 132.6 |
| 17 | 128.0 | 130.2 | 137.8 | 145.6 | 147.8 | 126.3 | 128.3 | 135.7 | 143.3 | 145.6 |
| 18 | 140.3 | 142.5 | 150.3 | 158.2 | 160.5 | 138.5 | 140.7 | 148.2 | 156.0 | 158.3 |
| 19 | 152.2 | 154.5 | 162.6 | 170.7 | 173.1 | 150.1 | 152.3 | 160.0 | 168.0 | 170.4 |
| 20 | 163.4 | 165.8 | 174.3 | 182.9 | 185.4 | 160.7 | 163.0 | 171.0 | 179.2 | 181.6 |
| 21 | 173.9 | 176.4 | 185.5 | 194.6 | 197.3 | 171.1 | 173.4 | 181.7 | 190.2 | 192.8 |
| 22 | 184.2 | 187.0 | 196.8 | 206.6 | 209.5 | 181.5 | 183.9 | 192.6 | 201.5 | 204.2 |
| 23 | 194.8 | 197.9 | 208.5 | 219.1 | 222.2 | 191.9 | 194.5 | 203.7 | 213.2 | 216.0 |
| 24 | 205.6 | 208.9 | 220.3 | 231.6 | 234.8 | 202.3 | 205.1 | 215.0 | 225.2 | 228.3 |
| 25 | 216.2 | 219.7 | 231.7 | 243.6 | 247.0 | 212.5 | 215.5 | 226.2 | 237.3 | 240.6 |
| 26 | 226.8 | 230.4 | 242.8 | 255.0 | 258.5 | 222.5 | 225.8 | 237.2 | 249.1 | 252.7 |
| 27 | 237.4 | 241.1 | 253.6 | 266.0 | 269.6 | 232.7 | 236.1 | 248.0 | 260.5 | 264.2 |
| 28 | 247.7 | 251.4 | 264.0 | 276.5 | 280.2 | 243.0 | 246.4 | 258.5 | 271.1 | 274.8 |
| 29 | 257.1 | 260.7 | 273.4 | 286.2 | 290.0 | 252.7 | 256.1 | 268.1 | 280.6 | 284.3 |
| 30 | 265.3 | 269.0 | 282.0 | 295.1 | 299.0 | 261.6 | 265.0 | 277.0 | 289.5 | 293.2 |
| 31 | 273.0 | 276.8 | 290.0 | 303.7 | 307.7 | 269.6 | 273.1 | 285.5 | 298.3 | 302.1 |
| 32 | 280.2 | 284.0 | 297.6 | 311.9 | 316.3 | 276.5 | 280.2 | 293.2 | 306.7 | 310.8 |
| 33 | 286.5 | 290.4 | 304.4 | 319.4 | 324.1 | 282.6 | 286.4 | 300.1 | 314.4 | 318.7 |
| 34 | 292.1 | 296.1 | 310.3 | 326.0 | 331.0 | 288.0 | 292.0 | 306.2 | 321.1 | 325.5 |
| 35 | 297.7 | 301.6 | 315.9 | 332.2 | 337.5 | 292.6 | 296.7 | 311.3 | 326.5 | 331.0 |
| 36 | 302.9 | 306.8 | 321.2 | 338.2 | 343.9 | 296.6 | 300.7 | 315.5 | 330.9 | 335.5 |
| 37 | 307.3 | 311.3 | 326.1 | 344.1 | 350.4 | 301.0 | 305.2 | 320.1 | 335.8 | 340.4 |
| 38 | 311.9 | 316.0 | 331.1 | 350.4 | 357.5 | 306.5 | 310.7 | 325.9 | 341.7 | 346.4 |
| 39 | 317.3 | 321.4 | 336.7 | 357.1 | 365.2 | 312.8 | 317.1 | 332.4 | 348.5 | 353.3 |
| 40 | 323.5 | 327.6 | 342.9 | 364.2 | 373.1 | 319.4 | 323.7 | 339.2 | 355.4 | 360.2 |
Reference values in millimeters for fetal head circumference (HC) for boys and girls for each gestational week for the median and 5th, 10th, 90th, and 95th centiles
GA gestational age