Fetal foot length--a new parameter for assessment of gestational age.

Ultrasonographic measurement of fetal foot length, a new parameter, was correlated with the gestation age. One hundred and five ultrasonographic measurement of fetal foot length was performed between 13 and 42 weeks gestation. Comparison of linear regression of foot length versus gestational age demonstrated a strong correlation with an r2 value of 0.84 (P less than 0.001). Ninety-five percent confidence intervals at each week compared favorably with both biparietal diameter and femur length data. Mean foot lengths at each week of gestation compared favorably with data based on pathological specimens described in 1920 (Streeter GL: Weight, sitting height, head size, foot length and menstrual age of the human embryo. Contrib Embryol Carnegie Inst. 11: 143, 1920). Measurement of fetal foot length is of particular use when other parameters do not accurately predict gestational age, e.g. hydrocephalus, anencephaly, short limb dysplasia. It can also be used in conjunction with biparietal diameter and femur length in the management of patients with premature labor in order to patients with premature labor in order to accurately predict gestational age. Hence the present study demonstrates that the ultrasonographic measurement of foot length is a reliable indicator of gestational age.