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Table 3 Percentiles for twin fetal sonography measurements by gestational age

From: Fetal growth standards for Chinese twin pregnancies

Gestational age, wks Percentiles
3rd 5th 10th 25th 50th 75th 90th 95th 97th
Biparietal diameter, mm (MC & DC twins)
 14 25.9 26.2 26.7 27.4 28.3 29.1 30.0 30.5 30.8
 15 28.7 29.0 29.5 30.3 31.3 32.2 33.1 33.7 34.0
 16 31.5 31.9 32.4 33.3 34.3 35.4 36.4 37.0 37.4
 17 34.5 34.8 35.4 36.4 37.5 38.7 39.8 40.4 40.8
 18 37.5 37.9 38.5 39.6 40.8 42.0 43.2 43.9 44.4
 19 40.5 40.9 41.6 42.7 44.1 45.4 46.7 47.4 47.9
 20 43.5 44.0 44.7 46.0 47.4 48.8 50.1 51.0 51.5
 21 46.6 47.1 47.8 49.2 50.6 52.2 53.6 54.5 55.1
 22 49.6 50.1 50.9 52.3 53.9 55.5 57.1 58.0 58.6
 23 52.6 53.1 54.0 55.5 57.1 58.9 60.5 61.4 62.1
 24 55.5 56.1 57.0 58.5 60.3 62.1 63.8 64.8 65.5
 25 58.3 58.9 59.9 61.5 63.3 65.2 67.0 68.1 68.8
 26 61.1 61.7 62.7 64.4 66.3 68.3 70.1 71.2 72.0
 27 63.7 64.3 65.4 67.1 69.1 71.2 73.1 74.3 75.0
 28 66.2 66.9 68.0 69.8 71.8 74.0 76.0 77.2 78.0
 29 68.6 69.3 70.4 72.3 74.4 76.6 78.7 79.9 80.7
 30 70.9 71.6 72.7 74.7 76.9 79.1 81.2 82.5 83.4
 31 73.0 73.8 74.9 76.9 79.2 81.5 83.7 85.0 85.8
 32 75.0 75.8 77.0 79.0 81.3 83.7 85.9 87.3 88.2
 33 76.9 77.7 78.9 81.0 83.4 85.8 88.1 89.4 90.3
 34 78.7 79.5 80.7 82.9 85.3 87.7 90.0 91.4 92.4
 35 80.4 81.2 82.4 84.6 87.0 89.6 91.9 93.3 94.3
 36 81.9 82.7 84.0 86.2 88.7 91.3 93.6 95.1 96.1
 37 83.4 84.2 85.5 87.7 90.3 92.9 95.3 96.8 97.7
 38 84.8 85.6 87.0 89.2 91.8 94.4 96.8 98.3 99.3
Head circumference, mm (MC & DC twins)
 14 92.4 93.2 94.6 96.8 99.4 102.1 104.6 106.1 107.1
 15 102.6 103.5 105.0 107.5 110.4 113.4 116.1 117.7 118.8
 16 113.2 114.2 115.8 118.6 121.8 125.0 128.0 129.8 131.0
 17 124.1 125.2 127.0 130.0 133.4 137.0 140.2 142.2 143.5
 18 135.2 136.4 138.3 141.6 145.3 149.2 152.7 154.8 156.3
 19 146.4 147.7 149.8 153.3 157.3 161.5 165.3 167.6 169.1
 20 157.7 159.1 161.3 165.1 169.4 173.8 177.9 180.4 182.0
 21 168.9 170.4 172.8 176.8 181.4 186.1 190.5 193.1 194.8
 22 180.0 181.6 184.1 188.4 193.3 198.2 202.9 205.7 207.5
 23 190.9 192.6 195.2 199.8 204.9 210.1 215.0 218.0 219.9
 24 201.5 203.3 206.1 210.8 216.2 221.7 226.8 230.0 232.0
 25 211.8 213.7 216.6 221.6 227.2 233.0 238.3 241.5 243.7
 26 221.7 223.7 226.7 231.9 237.7 243.8 249.3 252.7 254.9
 27 231.2 233.3 236.4 241.8 247.8 254.1 259.8 263.3 265.6
 28 240.3 242.4 245.6 251.2 257.4 263.9 269.8 273.5 275.8
 29 248.8 251.0 254.3 260.1 266.5 273.2 279.3 283.0 285.5
 30 256.9 259.1 262.6 268.4 275.1 281.9 288.2 292.0 294.5
 31 264.6 266.8 270.3 276.3 283.2 290.1 296.6 300.5 303.1
 32 271.7 274.0 277.6 283.7 290.7 297.8 304.4 308.4 311.0
 33 278.4 280.8 284.4 290.7 297.8 305.0 311.7 315.8 318.5
 34 284.7 287.1 290.8 297.2 304.4 311.8 318.6 322.8 325.5
 35 290.7 293.1 296.9 303.3 310.7 318.1 325.1 329.3 332.0
 36 296.3 298.7 302.6 309.1 316.5 324.1 331.1 335.4 338.2
 37 301.6 304.1 308.0 314.6 322.1 329.8 336.9 341.2 344.1
 38 306.8 309.3 313.2 319.9 327.5 335.3 342.5 346.8 349.7
Abdominal circumference, mm (MC & DC twins)
 14 77.8 78.7 80.1 82.5 85.3 88.2 90.9 92.5 93.6
 15 86.8 87.8 89.4 92.1 95.2 98.4 101.4 103.2 104.4
 16 96.3 97.4 99.1 102.1 105.5 109.1 112.4 114.4 115.7
 17 106.0 107.2 109.1 112.4 116.2 120.0 123.6 125.9 127.3
 18 116.0 117.3 119.4 123.0 127.1 131.3 135.2 137.6 139.2
 19 126.1 127.6 129.8 133.7 138.1 142.7 146.9 149.5 151.2
 20 136.4 138.0 140.4 144.5 149.3 154.2 158.8 161.6 163.4
 21 146.7 148.4 151.0 155.4 160.5 165.7 170.6 173.6 175.6
 22 157.0 158.7 161.5 166.2 171.7 177.2 182.4 185.6 187.7
 23 167.1 169.0 172.0 177.0 182.7 188.6 194.1 197.5 199.7
 24 177.2 179.2 182.3 187.6 193.6 199.9 205.7 209.2 211.6
 25 187.1 189.1 192.4 198.0 204.3 210.9 217.0 220.7 223.2
 26 196.7 198.9 202.3 208.1 214.8 221.7 228.0 231.9 234.5
 27 206.2 208.5 212.0 218.1 225.0 232.2 238.8 242.9 245.5
 28 215.4 217.8 221.4 227.8 235.0 242.4 249.3 253.5 256.3
 29 224.4 226.8 230.7 237.2 244.7 252.4 259.5 263.9 266.8
 30 233.2 235.7 239.6 246.4 254.1 262.1 269.5 274.0 277.0
 31 241.7 244.3 248.4 255.4 263.4 271.6 279.2 283.8 286.9
 32 250.1 252.8 257.0 264.2 272.4 280.9 288.7 293.5 296.7
 33 258.5 261.2 265.5 272.9 281.3 290.0 298.1 303.0 306.3
 34 266.7 269.5 274.0 281.6 290.2 299.1 307.4 312.4 315.8
 35 275.0 277.9 282.4 290.2 299.1 308.2 316.7 321.9 325.3
 36 283.3 286.3 291.0 298.9 308.0 317.4 326.1 331.4 334.9
 37 291.8 294.9 299.7 307.8 317.1 326.7 335.6 341.1 344.7
 38 300.6 303.8 308.7 317.0 326.6 336.4 345.5 351.1 354.7
Femur length, mm (MC & DC twins)
 14 13.1 13.3 13.6 14.1 14.7 15.3 15.9 16.3 16.5
 15 15.4 15.6 15.9 16.5 17.2 17.9 18.6 19.0 19.2
 16 17.8 18.0 18.4 19.1 19.8 20.6 21.4 21.8 22.1
 17 20.3 20.5 21.0 21.7 22.6 23.5 24.3 24.8 25.2
 18 22.9 23.2 23.6 24.5 25.4 26.4 27.4 27.9 28.3
 19 25.5 25.9 26.4 27.3 28.3 29.4 30.5 31.1 31.5
 20 28.2 28.6 29.1 30.1 31.3 32.5 33.6 34.2 34.7
 21 30.9 31.3 31.9 32.9 34.2 35.4 36.6 37.4 37.8
 22 33.5 33.9 34.6 35.7 37.0 38.4 39.7 40.4 40.9
 23 36.1 36.5 37.2 38.4 39.8 41.2 42.6 43.4 43.9
 24 38.5 39.0 39.7 41.0 42.5 44.0 45.4 46.2 46.8
 25 40.9 41.4 42.2 43.5 45.0 46.6 48.0 48.9 49.5
 26 43.2 43.7 44.5 45.8 47.4 49.0 50.5 51.5 52.1
 27 45.3 45.8 46.6 48.1 49.7 51.4 52.9 53.9 54.5
 28 47.3 47.9 48.7 50.2 51.8 53.5 55.1 56.1 56.7
 29 49.2 49.8 50.7 52.1 53.8 55.6 57.2 58.2 58.8
 30 51.1 51.6 52.5 54.0 55.7 57.5 59.2 60.2 60.8
 31 52.8 53.4 54.3 55.8 57.5 59.3 61.0 62.0 62.7
 32 54.5 55.1 56.0 57.5 59.3 61.1 62.8 63.8 64.5
 33 56.2 56.8 57.7 59.3 61.0 62.9 64.6 65.6 66.3
 34 57.9 58.5 59.4 61.0 62.8 64.6 66.3 67.4 68.1
 35 59.6 60.2 61.2 62.8 64.6 66.4 68.2 69.2 69.9
 36 61.5 62.1 63.0 64.6 66.5 68.3 70.1 71.1 71.8
 37 63.5 64.1 65.0 66.6 68.5 70.4 72.1 73.2 73.9
 38 65.6 66.3 67.2 68.9 70.7 72.7 74.4 75.5 76.2
  1. Note: MC monochorionic, DC dichorionic