title: Fetal skeletal dysplasias: sonographic indices associated with adverse outcomes.
abstract: OBJECTIVE
  To assess the utility of biometric indices and amniotic fluid volume in identifying fetuses with lethal skeletal dysplasia.
  
  
  METHODS
  A review of pregnancies with sonographic diagnosis of skeletal dysplasia between January 1997 and March 2012 from a single institution was conducted. Biometric indices and amniotic fluid volumes were reviewed from the initial targeted sonograms and all subsequent examinations. Outcomes were verified in all cases. Pregnancies that resulted in fetal or neonatal death were considered to have lethal dysplasia, and those with survival to hospital discharge were considered to have nonlethal dysplasia.
  
  
  RESULTS
  Of 45 fetuses with suspected skeletal dysplasia, 27 (60%) survived to hospital discharge; 9 (20%) died in the immediate neonatal period; 2 (4%) resulted in stillbirth; and in 7 cases (16%), pregnancy termination was elected. Those with lethal dysplasia were more likely to have hydramnios on initial detection than those who survived to hospital discharge (83% versus 27%; P < .01). Pregnancies complicated by lethal skeletal dysplasia had a significantly lower femur length-to-abdominal circumference ratio and were more likely to have a ratio below 0.16 than those with neonatal survival (91% versus 11%; P < 0.01). The lowest femur length-to-abdominal circumference ratio and the proportion with a ratio below 0.16 at any point in gestation were significantly different between those with lethal and nonlethal dysplasia (P< .01). As fetal size increased with advancing gestation, the relationship of sonographic parameters (eg, femur length-to-abdominal circumference ratio) became more pronounced. There was no infant survival when hydramnios was encountered at any point during gestation in the setting of a femur length-to-abdominal circumference ratio below 0.16.
  
  
  CONCLUSIONS
  In our series, a femur length-to-abdominal circumference ratio below 0.16 in conjunction with hydramnios effectively identified fetuses with lethal skeletal dysplasia.
authors.affiliation: Departments of Obstetrics and Gynecology (D.B.N., J.S.D., D.D.M.) and Radiology (D.M.T.), University of Texas Southwestern Medical Center, Dallas, Texas USA. davidb.nelson@utsouthwestern.edu.
authors.forename: David B
authors.initials: DB
authors.lastname: Nelson
authors.affiliation: Departments of Obstetrics and Gynecology (D.B.N., J.S.D., D.D.M.) and Radiology (D.M.T.), University of Texas Southwestern Medical Center, Dallas, Texas USA.
authors.forename: Jodi S
authors.initials: JS
authors.lastname: Dashe
authors.affiliation: Departments of Obstetrics and Gynecology (D.B.N., J.S.D., D.D.M.) and Radiology (D.M.T.), University of Texas Southwestern Medical Center, Dallas, Texas USA.
authors.forename: Donald D
authors.initials: DD
authors.lastname: McIntire
authors.affiliation: Departments of Obstetrics and Gynecology (D.B.N., J.S.D., D.D.M.) and Radiology (D.M.T.), University of Texas Southwestern Medical Center, Dallas, Texas USA.
authors.forename: Diane M
authors.initials: DM
authors.lastname: Twickler
mesh_terms: D000653:Amniotic Fluid / Q000000981:diagnostic imaging; D001699:Biometry / Q000379:methods; D001848:Bone Diseases, Developmental / Q000000981:diagnostic imaging* / Q000401:mortality*; D019465:Craniofacial Abnormalities / Q000000981:diagnostic imaging* / Q000401:mortality*; D005260:Female; D005313:Fetal Death; D017052:Hospital Mortality; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D015994:Incidence; D007231:Infant, Newborn; D008297:Male; D008954:Models, Biological; D015233:Models, Statistical; D064847:Multimodal Imaging / Q000379:methods*; D066087:Perinatal Death; D054238:Perinatal Mortality; D006831:Polyhydramnios / Q000000981:diagnostic imaging* / Q000401:mortality*; D011247:Pregnancy; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D015996:Survival Rate; D013781:Texas / Q000453:epidemiology; D016216:Ultrasonography, Prenatal / Q000706:statistics & numerical data*
keywords: obstetric ultrasound; pregnancy outcomes; skeletal dysplasia; sonography