title: Identification of pathologically small fetuses using customized, ultrasound and population-based growth norms.
abstract: OBJECTIVE
  Fetal growth restriction is a strong risk factor for stillbirth. We compared the performance of three fetal growth curves - customized, ultrasound (Hadlock) and population - in identifying abnormally grown fetuses at risk of stillbirth.
  
  
  METHODS
  We performed a case-control study of singleton stillbirths (delivered between 2000 and 2010) at one center. Four liveborn controls were randomly identified for each stillbirth. Ultrasound-estimated fetal weight within 1 month prior to delivery was used to calculate growth percentiles for each fetus using three fetal growth norms. Sensitivities and odds ratios for stillbirth, as well as odds of abnormal growth according to formula, were calculated.
  
  
  RESULTS
  There were 49 stillbirths and 197 live births. Using the customized norms, growth of the fetuses destined to be stillborn was bimodal, with both more small-for-gestational-age (SGA; < 10(th) percentile) and large-for-gestational-age (LGA; ≥ 90(th) percentile) fetuses. Odds of being abnormally grown were significantly higher using ultrasound compared with population norms (P = 0.02) but were not statistically different using ultrasound and customized norms (P = 0.21). Sensitivity for identification of SGA on ultrasound as a predictor of stillbirth was higher using customized (39%; 95% CI, 24-54%) or ultrasound (33%; 95% CI, 19-47%), rather than population (14%; 95% CI, 4-25%), norms.
  
  
  CONCLUSIONS
  Among fetuses destined to be stillborn, customized and ultrasound norms identified a greater proportion of both SGA and LGA estimated fetal weights. The customized norms performed best in identifying death among SGA fetuses. These results should be interpreted within the limitations of the study design.
authors: Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Boston, MA, USA.
authors: N A
authors: NA
authors: Smith
authors: R
authors: R
authors: Bukowski
authors: A M
authors: AM
authors: Thomas
authors: D
authors: D
authors: Cantonwine
authors: C
authors: C
authors: Zera
authors: J N
authors: JN
authors: Robinson
mesh_terms: D000328:Adult; D001835:Body Weight / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D047109:Fetal Development / Q000502:physiology; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging*; D020567:Fetal Weight / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000502:physiology*; D008423:Maternal Age; D016017:Odds Ratio; D011247:Pregnancy; D012015:Reference Standards; D012307:Risk Factors; D050497:Stillbirth; D016216:Ultrasonography, Prenatal
keywords: IUFD; IUGR; LGA; SGA; customized; fetal growth; growth potential; intrauterine fetal death; stillbirth