title: A randomized controlled trial of third-trimester routine ultrasound in a non-selected population.
abstract: OBJECTIVE
  To compare detection rates of small-for-gestational-age fetuses, large-for-gestational-age fetuses, congenital anomalies and adverse perinatal outcomes in pregnancies randomized to third-trimester routine ultrasound or ultrasound on clinical indication.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  National Center for Fetal Medicine in Norway between 1989 and 1992.
  
  
  METHODS
  A total of 6780 pregnancies from a non-selected population.
  
  
  METHODS
  Two routine ultrasound examinations at 18 and 33 weeks were compared with routine ultrasound at 18 weeks and ultrasound on clinical indication. Suspected small-for-gestational-age fetuses were followed with serial scans and cardiotocography. Doppler ultrasound was not used.
  
  
  METHODS
  Detection rates of small-for-gestational-age and large-for-gestational-age fetuses, congenital anomalies and adverse perinatal outcomes.
  
  
  RESULTS
  Third trimester routine ultrasound improved detection rates of small-for-gestational-age fetuses from 46 to 80%, but overall perinatal morbidity and mortality remained unchanged. Detection of large-for-gestational-age fetuses increased from 36 to 91%. There was a significant increase of induction of labor and elective cesarean sections due to suspected small-for-gestational-age and a significant decrease of induction of labor and elective cesarean sections due to suspected large-for-gestational-age in the study group; there were no other differences regarding intervention. The detection rate of congenital anomalies was 56%, with no significant difference between the groups.
  
  
  CONCLUSIONS
  Routine use of third-trimester routine ultrasound increased detection rates of small-for-gestational-age and large-for-gestational-age fetuses. This did not alter perinatal outcomes. Third-trimester ultrasound screening should not be rejected before a policy of adding Doppler surveillance to the high-risk group identified has been investigated further.
authors.affiliation: Faculty of Medicine, Department of Laboratory Medicine Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway; Department of Obstetrics and Gynecology, National Center for Fetal Medicine, St Olav's Hospital, Trondheim University Hospital, Trondheim, Norway.
authors.forename: Ragnhild B
authors.initials: RB
authors.lastname: Skråstad
authors.forename: Sturla H
authors.initials: SH
authors.lastname: Eik-Nes
authors.forename: Oddvar
authors.initials: O
authors.lastname: Sviggum
authors.forename: Ole J
authors.initials: OJ
authors.lastname: Johansen
authors.forename: Kjell Å
authors.initials: KÅ
authors.lastname: Salvesen
authors.forename: Pål R
authors.initials: PR
authors.lastname: Romundstad
authors.forename: Harm-Gerd K
authors.initials: HG
authors.lastname: Blaas
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002585:Cesarean Section / Q000706:statistics & numerical data; D000013:Congenital Abnormalities / Q000000981:diagnostic imaging*; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging*; D005320:Fetal Macrosomia / Q000000981:diagnostic imaging*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007751:Labor, Induced / Q000706:statistics & numerical data; D009664:Norway; D011247:Pregnancy; D011256:Pregnancy Outcome; D011263:Pregnancy Trimester, Third; D016216:Ultrasonography, Prenatal / Q000379:methods* / Q000706:statistics & numerical data
keywords: Pregnancy; intrauterine growth restriction; large-for-gestational-age; perinatal outcome; routine ultrasound; small-for-gestational-age; third trimester