Fetal short femur length in the second trimester and the outcome of pregnancy

We reviewed 86 consecutive cases with fetal femur length (FL) below the 10th centile of our reference ranges at midtrimester ultrasonography. Three groups were identified based on perinatal outcome: normal infants (n= 28), newborns with structural and/or chromosomal anomalies (n= 40), small-for-gestational age (SGA) newborns (n= 18). Fetuses with skeletal dysplasias (n= 13) had significantly shorter FL. Aneuploidies were only found in fetuses with malformations other than skeletal dysplasias. The diagnosis of SGA, based on ultrasound abdominal circumference measurement <10th centile, was made 9 weeks (range 5-14) after the finding of a short FL. Half of these cases also developed pre-eclampsia.