title: Prediction of small-for-gestational-age neonates: screening by fetal biometry at 30-34 weeks.
abstract: OBJECTIVE
  To investigate the value of fetal biometry at 30-34 weeks' gestation in the prediction of delivery of small-for-gestational-age (SGA) neonates, in the absence of pre-eclampsia (PE).
  
  
  METHODS
  This was a screening study in 30 849 singleton pregnancies at 30-34 weeks' gestation, comprising 1727 that delivered SGA neonates with a birth weight < 5(th) percentile and 29 122 cases unaffected by SGA, PE or gestational hypertension. Multivariable logistic regression analysis was used to determine if screening by a combination of maternal factors and Z-scores of fetal head circumference (HC), abdominal circumference (AC) and femur length (FL) or estimated fetal weight (EFW) had a significant contribution to the prediction of SGA neonates.
  
  
  RESULTS
  Combined screening by maternal characteristics and obstetric history, with Z-scores of EFW at 30-34 weeks, predicted 79%, 87% and 92% of the SGA neonates that delivered < 5 weeks following assessment, with a birth weight < 10(th) , < 5(th) and < 3(rd) percentiles, respectively, at a 10% false-positive rate. The respective detection rates for the prediction of SGA neonates delivering ≥ 5 weeks from the time of assessment were 53%, 58% and 61%. The performance of screening by a combination of Z-scores of fetal HC, AC and FL was similar to that achieved by the EFW Z-score alone.
  
  
  CONCLUSIONS
  Combined testing by maternal characteristics and fetal biometry at 30-34 weeks could identify a high proportion of pregnancies that will deliver SGA neonates.
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
authors.forename: S
authors.initials: S
authors.lastname: Bakalis
authors.forename: M
authors.initials: M
authors.lastname: Silva
authors.forename: R
authors.initials: R
authors.lastname: Akolekar
authors.forename: L C
authors.initials: LC
authors.lastname: Poon
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000328:Adult; D001699:Biometry / Q000379:methods*; D001724:Birth Weight; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging*; D020567:Fetal Weight; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008297:Male; D008423:Maternal Age; D011237:Predictive Value of Tests; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal
keywords: abdominal circumference; estimated fetal weight; fetal biometry; pre-eclampsia; pyramid of antenatal care; small-for-gestational age; third-trimester screening