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. Author manuscript; available in PMC: 2017 Aug 1.
Published in final edited form as: Am J Obstet Gynecol. 2016 Apr 30;215(2):221.e1–221.e16. doi: 10.1016/j.ajog.2016.04.044

Table 2.

Percentiles for dichorionic twin fetal anthropometric measurements by gestational age.

Biparietal Diameter (mm) – Dichorionic Twin
Gestational age, weeks 10th 25th 50th 75th 90th
11 13.6 14.2 14.9 15.6 16.3
12 17.2 17.9 18.8 19.7 20.5
13 20.9 21.7 22.7 23.8 24.7
14 24.5 25.5 26.6 27.8 28.9
15 28.0 29.1 30.4 31.6 32.9
16 31.4 32.6 33.9 35.3 36.6
17 34.6 35.8 37.3 38.8 40.2
18 37.8 39.1 40.6 42.2 43.7
19 40.9 42.3 43.9 45.6 47.1
20 43.9 45.4 47.1 48.8 50.5
21 46.9 48.5 50.2 52.1 53.8
22 49.8 51.4 53.3 55.2 57
23 52.7 54.4 56.3 58.3 60.1
24 55.5 57.3 59.3 61.3 63.3
25 58.3 60.1 62.2 64.4 66.4
26 61.0 62.9 65.1 67.3 69.4
27 63.7 65.6 67.9 70.2 72.4
28 66.2 68.2 70.6 73.0 75.3
29 68.6 70.7 73.1 75.7 78.0
30 70.8 73.0 75.5 78.2 80.6
31 72.8 75.1 77.7 80.4 82.9
32 74.7 77.0 79.7 82.5 85.1
33 76.4 78.8 81.5 84.4 87.1
34 77.9 80.4 83.2 86.1 88.9
35 79.3 81.9 84.8 87.8 90.6
36 80.7 83.3 86.3 89.4 92.3
37 82.0 84.7 87.8 91 93.9
38 83.3 86.1 89.3 92.6 95.7
Head Circumference (mm) – Dichorionic Twin
Gestational age, weeks 10th 25th 50th 75th 90th
11 52.8 55.0 57.5 60.1 62.5
12 65.4 68.0 70.9 74.0 76.8
13 78.3 81.3 84.7 88.2 91.5
14 91.3 94.5 98.3 102.3 105.9
15 103.9 107.5 111.6 115.9 119.9
16 116.1 120.0 124.4 129.0 133.3
17 128.0 132.1 136.8 141.7 146.2
18 139.9 144.2 149.1 154.2 158.9
19 151.6 156 161.2 166.5 171.4
20 163.1 167.7 173 178.5 183.6
21 174.4 179.2 184.7 190.3 195.5
22 185.5 190.4 196.0 201.8 207.2
23 196.3 201.4 207.2 213.2 218.7
24 207.1 212.3 218.2 224.3 230
25 217.7 223.0 229.1 235.4 241.2
26 228.0 233.5 239.8 246.3 252.2
27 238.1 243.8 250.2 256.9 263
28 247.7 253.6 260.3 267.1 273.4
29 256.9 262.9 269.8 276.9 283.4
30 265.4 271.7 278.8 286.1 292.9
31 273.3 279.7 287.1 294.7 301.6
32 280.4 287.1 294.7 302.6 309.8
33 286.9 293.8 301.7 309.8 317.3
34 292.7 299.9 308.1 316.4 324.2
35 298.0 305.4 313.8 322.5 330.5
36 302.8 310.4 319.1 328.1 336.4
37 307.0 315.0 324.0 333.3 341.9
38 310.9 319.1 328.5 338.3 347.2
Abdominal Circumference (mm) – Dichorionic Twin
Gestational age, weeks 10th 25th 50th 75th 90th
11 38.9 41.2 43.9 46.8 49.6
12 48.7 51.5 54.8 58.3 61.6
13 59.1 62.4 66.3 70.4 74.3
14 70.0 73.8 78.2 82.9 87.4
15 81.0 85.2 90.2 95.6 100.6
16 92.0 96.7 102.3 108.1 113.7
17 103.0 108.2 114.2 120.6 126.7
18 114.0 119.6 126.2 133.1 139.6
19 125.0 131.0 138 145.4 152.4
20 135.9 142.3 149.8 157.6 165
21 146.5 153.3 161.2 169.6 177.4
22 157.0 164.1 172.5 181.2 189.5
23 167.2 174.7 183.5 192.7 201.4
24 177.2 185.1 194.3 204.0 213.1
25 187.2 195.4 205.1 215.2 224.7
26 197.0 205.6 215.7 226.2 236.2
27 206.6 215.6 226.1 237.1 247.5
28 216.0 225.4 236.4 247.9 258.7
29 225.2 235.0 246.5 258.4 269.7
30 234.3 244.5 256.4 268.8 280.6
31 243.1 253.8 266.1 279.1 291.3
32 251.8 262.9 275.7 289.2 301.9
33 260.4 271.8 285.2 299.2 312.3
34 268.7 280.6 294.4 309.0 322.6
35 276.9 289.2 303.6 318.6 332.8
36 284.9 297.7 312.5 328.2 342.9
37 292.7 306.0 321.4 337.6 352.9
38 300.2 314.0 330.1 347.0 363.0
Femur Length (mm) – Dichorionic Twin
Gestational age, weeks 10th 25th 50th 75th 90th
11 3.5 3.8 4.1 4.4 4.8
12 5.6 6.0 6.5 7.0 7.5
13 8.3 8.8 9.5 10.2 10.9
14 11.2 11.9 12.8 13.7 14.5
15 14.3 15.2 16.1 17.2 18.2
16 17.4 18.3 19.4 20.6 21.7
17 20.3 21.4 22.6 23.9 25.1
18 23.3 24.4 25.7 27.1 28.4
19 26.2 27.4 28.8 30.3 31.6
20 29.0 30.3 31.8 33.3 34.8
21 31.7 33.0 34.6 36.2 37.8
22 34.2 35.6 37.3 39.0 40.6
23 36.6 38.1 39.8 41.7 43.4
24 38.9 40.5 42.3 44.3 46.1
25 41.1 42.8 44.7 46.8 48.7
26 43.2 45.0 47.1 49.3 51.3
27 45.3 47.2 49.4 51.7 53.9
28 47.3 49.3 51.6 54 56.3
29 49.2 51.3 53.7 56.3 58.7
30 51.1 53.3 55.8 58.5 61.0
31 52.9 55.2 57.8 60.6 63.2
32 54.7 57.1 59.8 62.6 65.3
33 56.5 58.9 61.6 64.6 67.3
34 58.2 60.6 63.5 66.4 69.3
35 59.8 62.3 65.2 68.3 71.1
36 61.3 63.9 66.9 70.0 73.0
37 62.8 65.4 68.5 71.8 74.8
38 64.0 66.8 70.1 73.5 76.7
Humerus Length (mm) – Dichorionic Twin
Gestational age, weeks 10th 25th 50th 75th 90th
11 3.5 3.8 4.1 4.5 4.8
12 5.9 6.3 6.8 7.3 7.8
13 8.7 9.3 10.0 10.7 11.4
14 11.8 12.5 13.4 14.4 15.3
15 14.9 15.8 16.8 17.9 18.9
16 17.8 18.8 19.9 21.1 22.3
17 20.5 21.6 22.8 24.1 25.4
18 23.2 24.3 25.6 27.0 28.3
19 25.8 26.9 28.3 29.7 31.1
20 28.2 29.4 30.9 32.4 33.7
21 30.5 31.8 33.3 34.8 36.3
22 32.7 34.0 35.5 37.1 38.6
23 34.7 36.1 37.7 39.3 40.8
24 36.7 38.1 39.7 41.4 43.0
25 38.5 40.0 41.7 43.5 45.1
26 40.2 41.8 43.6 45.4 47.2
27 41.9 43.5 45.4 47.4 49.2
28 43.5 45.2 47.1 49.2 51.1
29 44.9 46.7 48.8 51.0 53.0
30 46.4 48.2 50.4 52.7 54.8
31 47.7 49.7 52.0 54.3 56.6
32 49.1 51.1 53.5 55.9 58.2
33 50.3 52.4 54.9 57.4 59.9
34 51.5 53.7 56.2 58.9 61.4
35 52.7 54.9 57.6 60.3 62.8
36 53.8 56.1 58.8 61.6 64.2
37 54.8 57.2 60.0 62.9 65.6
38 55.8 58.2 61.1 64.1 66.9
Estimated Fetal Weight (grams) – Dichorionic Twin
Gestational age, weeks 10th 25th 50th 75th 90th
15 97.0 103.7 111.7 120.3 128.6
16 122.6 131.1 141.2 152.1 162.6
17 153.7 164.4 177.1 190.7 204.0
18 190.6 203.9 219.7 236.7 253.2
19 233.8 250.2 269.7 290.7 311.0
20 283.9 303.8 327.6 353.2 378.0
21 341.2 365.4 394.1 425.2 455.2
22 406.4 435.4 469.9 507.3 543.4
23 479.8 514.3 555.6 600.1 643.3
24 561.9 602.8 651.7 704.5 755.8
25 653.0 701.1 758.7 821.1 881.6
26 753.0 809.3 876.9 950.1 1021.2
27 861.8 927.5 1006.2 1091.7 1174.8
28 979.1 1055.1 1146.6 1245.9 1342.7
29 1104.2 1191.9 1297.5 1412.4 1524.6
30 1236.4 1337.0 1458.4 1590.8 1720.2
31 1374.7 1489.6 1628.5 1780.4 1929.2
32 1517.8 1648.4 1806.7 1980.2 2150.6
33 1664.2 1812.0 1991.6 2189.1 2383.5
34 1812.3 1978.8 2181.8 2405.7 2626.7
35 1960.3 2147.1 2375.5 2628.3 2878.6
36 2106.4 2314.9 2570.9 2855.1 3137.8
37 2248.1 2480 2765.9 3084.7 3402.9
38 2382.5 2639.8 2958.4 3315.5 3673.5
Head Circumference / Abdominal Circumference – Dichorionic Twin
Gestational age, weeks 10th 25th 50th 75th 90th
11 1.187 1.242 1.306 1.373 1.437
12 1.18 1.233 1.294 1.359 1.419
13 1.167 1.218 1.277 1.34 1.398
14 1.152 1.201 1.258 1.318 1.374
15 1.135 1.182 1.237 1.295 1.349
16 1.118 1.163 1.217 1.272 1.324
17 1.102 1.146 1.197 1.251 1.301
18 1.088 1.131 1.181 1.233 1.282
19 1.076 1.118 1.167 1.217 1.265
20 1.065 1.107 1.155 1.204 1.251
21 1.057 1.097 1.144 1.193 1.239
22 1.049 1.089 1.136 1.184 1.23
23 1.042 1.082 1.128 1.177 1.222
24 1.036 1.076 1.122 1.17 1.215
25 1.031 1.071 1.116 1.164 1.209
26 1.026 1.066 1.111 1.159 1.203
27 1.021 1.06 1.106 1.153 1.198
28 1.015 1.055 1.100 1.148 1.192
29 1.009 1.048 1.094 1.141 1.186
30 1.002 1.041 1.086 1.134 1.178
31 0.993 1.033 1.078 1.125 1.169
32 0.984 1.023 1.068 1.115 1.159
33 0.973 1.012 1.057 1.103 1.147
34 0.962 1.001 1.045 1.092 1.135
35 0.951 0.989 1.033 1.079 1.122
36 0.939 0.977 1.021 1.067 1.11
37 0.928 0.966 1.009 1.055 1.098
38 0.916 0.954 0.998 1.044 1.087
Femoral Length / Abdominal Circumference – Dichorionic Twin
Gestational age, weeks 10th 25th 50th 75th 90th
11 0.079 0.086 0.093 0.102 0.11
12 0.102 0.11 0.119 0.129 0.139
13 0.124 0.133 0.143 0.154 0.165
14 0.142 0.152 0.163 0.175 0.187
15 0.157 0.167 0.179 0.191 0.203
16 0.168 0.178 0.190 0.202 0.214
17 0.176 0.186 0.197 0.210 0.222
18 0.182 0.192 0.204 0.216 0.228
19 0.187 0.197 0.208 0.221 0.232
20 0.190 0.200 0.212 0.224 0.236
21 0.193 0.203 0.214 0.226 0.238
22 0.195 0.204 0.216 0.228 0.239
23 0.196 0.205 0.217 0.229 0.240
24 0.196 0.206 0.217 0.229 0.241
25 0.196 0.206 0.218 0.23 0.241
26 0.196 0.206 0.218 0.23 0.242
27 0.196 0.206 0.218 0.23 0.242
28 0.196 0.206 0.218 0.23 0.242
29 0.196 0.206 0.218 0.23 0.242
30 0.195 0.205 0.217 0.23 0.242
31 0.195 0.205 0.217 0.229 0.241
32 0.194 0.204 0.216 0.229 0.241
33 0.194 0.204 0.216 0.228 0.240
34 0.193 0.203 0.215 0.227 0.239
35 0.193 0.203 0.214 0.227 0.238
36 0.192 0.202 0.213 0.226 0.238
37 0.191 0.201 0.213 0.225 0.237
38 0.190 0.200 0.212 0.225 0.236