title: Safety of MR Imaging at 1.5 T in Fetuses: A Retrospective Case-Control Study of Birth Weights and the Effects of Acoustic Noise.
abstract: OBJECTIVE
  To evaluate the effects of exposure to routine magnetic resonance (MR) imaging at 1.5 T during pregnancy on fetal growth and neonatal hearing function in relation to the dose and timing of in utero exposure in a group of newborns at low risk for congenital hearing impairment or deafness.
  
  
  METHODS
  This retrospective case-control study was approved by the local ethics committee, and written informed consent was waived. Between January 2008 and December 2012, a group of 751 neonates exposed to MR imaging in utero and a group of control subjects comprising 10 042 nonexposed neonates, both groups with no risk factors for hearing impairment at birth, were included. Neonatal hearing screening was performed by means of otoacoustic emission testing and auditory brain stem response according to national guidelines, and the prevalence of hearing impairment in the two groups was compared by using a noninferiority test with Wilson score confidence intervals. The effect of MR exposure on birth weight percentile was examined between the singleton neonates in the exposed group and a randomly chosen subset of 1805 singleton newborns of the nonexposed group by performing an analysis of variance.
  
  
  RESULTS
  The rate of hearing impairment or deafness was found to be 0% (0 of 751) in the neonates in the exposed group and was not inferior to that in the nonexposed group (34 of 10 042 [0.34%], P < .05). There was no between-group difference in birth weight percentiles (50.6% for exposed vs 48.4% for nonexposed; P = .22).
  
  
  CONCLUSIONS
  This study showed no adverse effects of exposure to 1.5-T MR imaging in utero on neonatal hearing function or birth weight percentiles.
authors.affiliation: From the Departments of Obstetrics and Gynecology (B.S., J.C.J., S.Z., T.C.), Radiology (E.M., M.M.C.), and Neurology (P.D.), University Hospital Brugmann, Place A. Van Gehuchten 4, 1020 Brussels, Belgium; Department of Radiology, University Hospitals Leuven, Leuven, Belgium (F.D.K.); Department of Pediatric Otorhinolaryngology, University Children's Hospital Reine Fabiola, Brussels, Belgium (I.P., A.L.M.); and Department of Radiology, UZ Brussel, Vrije Universiteit Brussels, Belgium (M.M.C.).
authors.forename: Brigitte
authors.initials: B
authors.lastname: Strizek
authors.forename: Jacques C
authors.initials: JC
authors.lastname: Jani
authors.forename: Eugène
authors.initials: E
authors.lastname: Mucyo
authors.forename: Frederik
authors.initials: F
authors.lastname: De Keyzer
authors.forename: Inge
authors.initials: I
authors.lastname: Pauwels
authors.forename: Samir
authors.initials: S
authors.lastname: Ziane
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Mansbach
authors.forename: Paul
authors.initials: P
authors.lastname: Deltenre
authors.forename: Teresa
authors.initials: T
authors.lastname: Cos
authors.forename: Mieke M
authors.initials: MM
authors.lastname: Cannie
mesh_terms: D001724:Birth Weight / Q000528:radiation effects*; D016022:Case-Control Studies; D005260:Female; D005333:Fetus / Q000528:radiation effects*; D005865:Gestational Age; D006309:Hearing / Q000528:radiation effects*; D006801:Humans; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000009:adverse effects* / Q000379:methods; D008297:Male; D009622:Noise / Q000009:adverse effects*; D011247:Pregnancy; D011829:Radiation Dosage; D012189:Retrospective Studies