Is fetal femur length a better indicator of gestational age in the growth-retarded fetus as compared with biparietal diameter?

The accuracy of gestational age prediction in 30 growth-retarded fetuses as derived from the fetal femur length (FL) was compared with that derived from the biparietal diameter (BPD). The mean difference between the actual and predicted gestational age was smaller when FL was used, but the difference did not reach statistical significance when compared with that associated with the use of the BPD. No consistent pattern of head/limb growth retardation was obvious. The femur length and BPD were both reduced in varying proportions in the growth-retarded fetuses. The significance of such findings in the assessment of intrauterine growth retardation is discussed.