title: Ultrasound fetal femur length measurement in the screening for Down's syndrome.
abstract: The fetal femur length determined by an ultrasound examination at between 13 and 39 weeks gestation in 83 pregnancies associated with Down's syndrome was statistically significantly less than the expected value for pregnancies with the same biparietal diameter examined in the same ultrasound department (P less than 0.0001). Expected values were based on linear regressions of femur length on biparietal diameter in 1340 control pregnancies from 27 ultrasound departments. The median value for the affected pregnancies was 0.94 times the expected value (95% CI 0.92 to 0.97). Eleven per cent of affected and 1.4% of control pregnancies had values less than or equal to 0.85 times the expected. The reduction in femur length in affected pregnancies was not related to biparietal diameter or to maternal age. Fetal femur length may be useful as an ancillary screening variable in the antenatal screening for Down's syndrome.
authors.affiliation: Department of Environmental and Preventive Medicine, Medical College of St Bartholomew's Hospital, London.
authors.forename: H
authors.initials: H
authors.lastname: Cuckle
authors.forename: N
authors.initials: N
authors.lastname: Wald
authors.forename: J
authors.initials: J
authors.lastname: Quinn
authors.forename: P
authors.initials: P
authors.lastname: Royston
authors.forename: L
authors.initials: L
authors.lastname: Butler
mesh_terms: D004314:Down Syndrome / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D005269:Femur / Q000473:pathology*; D005315:Fetal Diseases / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D014463:Ultrasonography