| 孕期正常参数值 | |||
| 孕周 | 双顶径(平均值)cm | 腹围(平均值)cm | 股骨长(平均值)cm |
| 16周 | 3.62士0.58 | 10.32士1.92 | 2.10士0.51 |
| 18周 | 4.25士0.53 | 12.41士l.89 | 2.71士0.46 |
| 20周 | 4.88士0.58 | 14.80士l.89 | 3.35士O.47 |
| 22周 | 5.45士0.57 | 16.70士2.23 | 3.82士0.47 |
| 24周 | 6.05士0.50 | 18.74士2.23 | 4.36士0.51 |
| 26周 | 6.68士0.61 | 21.62士2.30 | 4.87士O.41 |
| 28周 | 7.24士O.65 | 22.86士2.41 | 5.35士0.55 |
| 30周 | 7.83士0.62 | 24.88士2.03 | 5.77士0.47 |
| 32周 | 8.17士0.65 | 26.20士2.33 | 6.43士0.49 |
| 34周 | 8.61士0.63 | 27.99士2.55 | 6.62士0.43 |
| 36周 | 8.81士0.57 | 29.44士2.83 | 6.95士0.47 |
| 38周 | 9.08士0.59 | 30.63士2.83 | 7.20士0.43 |
| 39周 | 9.21士0.59 | 31.34士3.12 | 7.34士0.53 |
| 40周 | 9.28士0.50 | 31.49士2.79 | 7.40士0.53 |