表1正常妊娠胎头双顶径值（cm）孕周均值±标准差孕周均值±标准差112.08±0.577266.31±0.773122.35±0.525276.67±0.820132.58±0.515287.09±0.403143.03±0.757297.23±0.682153.45±0.580307.39±0.802163.79±0.358317.93±0.636174.10±0.820327.94±0.580184.28±0.406338.13±0.367194.26±0.630348.30±0.628204.68±0.711358.47±0.614214.79±0.681368.52±0.515225.15±0.568378.71±0.566235.47±1.000388.88±0.354245.80±0.704398.91±0.536255.81±1.380409.09±0.429表2头围（HC）及腹围（AC）的正常均值（cm）孕周HCAC孕周HCAC127.05.62725.222.9138.96.92826.224.0149.88.12927.125.01511.19.33028.026.01612.410.53128.927.01713.711.73229.728.01815.012.93330.429.01916.314.13431.230.02017.515.23531.830.92118.716.43632.531.82219.917.53733.032.72321.018.63833.633.62422.119.73934.134.52523.220.84034.535.42624.221.9表3股骨长度正常值（cm）孕周股骨长度孕周股骨长度孕周股骨长度120.8223.9326.3131.1234.2336.5141.5244.4346.6151.8254.7356.8162.1264.9367.0172.4275.2377.2182.7285.4387.3193.0295.6397.5203.3305.8407.6213.6316.1
