title: Maternal prenatal weight gain and autism spectrum disorders.
abstract: BACKGROUND
  The rising population of individuals identified with an autism spectrum disorder (ASD) calls for further investigation of its underlying etiology. A disturbance in the fetal steroid hormone environment may be a mechanism in which environmental and genetic risk factors interact. The mother, fetus, and placenta collectively create the fetal steroid environment. Prepregnancy BMI and pregnancy weight gain have served as markers for fetal steroid hormone exposure in other disease states. This study's objective is to determine whether prepregnancy BMI and pregnancy weight gain are associated with increased ASD risk across study designs and cohorts while controlling for important confounding variables.
  
  
  METHODS
  A population-based Utah ASD cohort (n = 128) was ascertained in a 3-county surveillance area and gender- and age-matched to 10,920 control subjects. A second, research-based ASD cohort of Utah children (n = 288) and their unaffected siblings (n = 493) were ascertained through participation in an ASD genetics study. Prenatal variables were obtained from birth certificate records.
  
  
  RESULTS
  ASD risk was significantly associated with pregnancy weight gain (adjusted odds ratio = 1.10, 95% confidence interval: 1.03 to 1.17; adjusted odds ratio = 1.17, 95% confidence interval: 1.01 to 1.35 for each 5 pounds of weight gained), but not prepregnancy BMI, in population and research-based cohorts, respectively. When analyses were restricted to ASD cases with normal IQ, these associations remained significant.
  
  
  CONCLUSIONS
  ASD risk associated with a modest yet consistent increase in pregnancy weight gain suggests that pregnancy weight gain may serve as an important marker for autism's underlying gestational etiology. This justifies an investigation into phenomena that link pregnancy weight gain and ASD independent of prepregnancy BMI.
authors.affiliation: Utah Autism Research Program, 650 Komas Dr, Suite 206, Salt Lake City, UT 84108. deborah.bilder@hsc.utah.edu.
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Bilder
authors.forename: Amanda V
authors.initials: AV
authors.lastname: Bakian
authors.forename: Joseph
authors.initials: J
authors.lastname: Viskochil
authors.forename: Erin A S
authors.initials: EA
authors.lastname: Clark
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Botts
authors.forename: Ken R
authors.initials: KR
authors.lastname: Smith
authors.forename: Richard
authors.initials: R
authors.lastname: Pimentel
authors.forename: William M
authors.initials: WM
authors.lastname: McMahon
authors.forename: Hilary
authors.initials: H
authors.lastname: Coon
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D002659:Child Development Disorders, Pervasive / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D014589:Utah / Q000453:epidemiology; D015430:Weight Gain / Q000502:physiology*; D055815:Young Adult
keywords: autism; epidemiology; prenatal; risk factors; weight gain