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

13周                 2.52±0.25        6.90±1.65                   1.17±0.31

14周                 2.83±0.57        7.77±1.82                   1.38±0.48

15周                 3.23±0.51        9.13±1.56                   1.74±0.58

16周                 3.62±0.58        10.32±1.92                 2.10±0.51

18周                 3.25±0.53        12.41±1.89                 2.71±0.46

20周                 4.88±0.58        14.80±1.89                 3.35±0.47

22周                 5.45±0.57        16.70±2.23                 3.82±0.47

24周                 6.05±0.50        18.74±2.23                 4.36±0.51

26周                 6.68±0.61        21.62±2.30                 4.87±0.41

28周                 7.24±0.65        22.86±2.41                 5.35±0.55

30周                 7.83±0.62        24.88±2.03                 5.77±0.47

32周                 8.17±0.65        26.20±2.33                 6.43±0.49

34周                 8.61±0.63        27.99±2.55                 6.62±0.43

36周                 8.81±0.57        29.44±2.83                 6.95±0.47

38周                 9.08±0.59        30.63±2.83                 7.20±0.43

39周                 9.21±0.59        31.34±3.12                 7.34±0.53

40周                 9.28±0.50        31.49±2.79                 7.40±0.53