title: Ultrasound for fetal assessment in early pregnancy.
abstract: BACKGROUND
  Diagnostic ultrasound is a sophisticated electronic technology, which utilises pulses of high frequency sound to produce an image. Diagnostic ultrasound examination may be employed in a variety of specific circumstances during pregnancy such as after clinical complications, or where there are concerns about fetal growth. Because adverse outcomes may also occur in pregnancies without clear risk factors, assumptions have been made that routine ultrasound in all pregnancies will prove beneficial by enabling earlier detection and improved management of pregnancy complications. Routine screening may be planned for early pregnancy, late gestation, or both. The focus of this review is routine early pregnancy ultrasound.
  
  
  OBJECTIVE
  To assess whether routine early pregnancy ultrasound for fetal assessment (i.e. its use as a screening technique) influences the diagnosis of fetal malformations, multiple pregnancies, the rate of clinical interventions, and the incidence of adverse fetal outcome when compared with the selective use of early pregnancy ultrasound (for specific indications).
  
  
  METHODS
  We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2009).
  
  
  METHODS
  Published, unpublished, and ongoing randomised controlled trials that compared outcomes in women who experienced routine versus selective early pregnancy ultrasound (i.e. less than 24 weeks' gestation). We have included quasi-randomised trials.
  
  
  METHODS
  Two review authors independently extracted data for each included study. We used the Review Manager software to enter and analyse data.
  
  
  RESULTS
  Routine/revealed ultrasound versus selective ultrasound/concealed: 11 trials including 37505 women. Ultrasound for fetal assessment in early pregnancy reduces the failure to detect multiple pregnancy by 24 weeks' gestation (risk ratio (RR) 0.07, 95% confidence interval (CI) 0.03 to 0.17). Routine scan is associated with a reduction in inductions of labour for 'post term' pregnancy (RR 0.59, 95% CI 0.42 to 0.83). Routine scans do not seem to be associated with reductions in adverse outcomes for babies or in health service use by mothers and babies. Long-term follow up of children exposed to scan in utero does not indicate that scans have a detrimental effect on children's physical or cognitive development.
  
  
  CONCLUSIONS
  Early ultrasound improves the early detection of multiple pregnancies and improved gestational dating may result in fewer inductions for post maturity. Caution needs to be exercised in interpreting the results of aspects of this review in view of the fact that there is considerable variability in both the timing and the number of scans women received.
authors.affiliation: St Mary's Hospital, Central Manchester and Manchester Children's University Hospitals NHS Trust, Hathersage Road, Manchester, UK, M13 0JH.
authors.forename: Melissa
authors.initials: M
authors.lastname: Whitworth
authors.forename: Leanne
authors.initials: L
authors.lastname: Bricker
authors.forename: James P
authors.initials: JP
authors.lastname: Neilson
authors.forename: Therese
authors.initials: T
authors.lastname: Dowswell
mesh_terms: D000013:Congenital Abnormalities / Q000000981:diagnostic imaging; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D005865:Gestational Age; D006801:Humans; D054238:Perinatal Mortality; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011272:Pregnancy, Multiple; D016216:Ultrasonography, Prenatal / Q000379:methods*
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