Supplementary text

METHODS

The following terms were used for database search:

PubMed/MEDLINE:

#1."Child Development Disorders, Pervasive"[Mesh] or "Asperger Syndrome"[Mesh] or "Autistic Disorder"[Mesh] or autism or autistic disorder or Asperger syndrome or pervasive developmental disorder

#2.("Diabetes, Gestational"[Mesh] or "Diabetes Mellitus"[Mesh] or diabetes or hyperglycemia or glucose) and (maternal or mother or parent or gestational or pregnancy or prenatal or perinatal)

#3.#1 and #2 not (review[pt] or editorial[pt] or comment[pt])

EMBASE:

#1.'autism'/exp or 'Asperger syndrome'/exp or 'pervasive developmental disorder not otherwise specified'/exp or autism or “autistic disorder” or “Asperger syndrome” or “pervasive developmental disorder”

#2.('diabetes mellitus'/exp or 'pregnancy diabetes mellitus'/exp or diabetes or hyperglycemia or glucose) and (maternal or mother or parent or gestational or pregnancy or prenatal or perinatal)

#3.#1 and #2 and ([embase]/lim or [embase classic]/lim) and ('article'/it or 'article in press'/it)

PsychINFO:

Any Field: autism and Any Field: diabetes and (peer-reviewed journals only)

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Supplementary Table 1. Critical appraisal of the included cohort studies using the Newcastle-Ottawa Quality Assessment Scale

Selection / Comparability / Outcome / Total scores
Representativeness of the exposed cohort / Selection of the non-exposed cohort / Ascertainment of exposure / Demonstration that outcome of interest was not present at start of study / Comparability of cohorts on the basis / Assessment of outcome / Was follow-up long enough for outcomes to occur / Adequacy of follow up of cohorts
Burstyn et al, 2010 / * / * / * / * / ** / * / * / * / 9
Dodds et al, 2011 / * / * / * / * / * / * / 6
Lyall et al, 2011 / * / * / ** / * / 5

Supplementay Table 2. Critical appraisal of the included case-control studies using the Newcastle-Ottawa Quality Assessment Scale

Selection / Comparability / Exposure / Total scores
Is the case definition adequate? / Representativeness of the cases / Selection of controls / Definition of controls / Comparability of cases and controls / Ascertainment of exposure / Same method of ascertainment for groups / Non-response rate
Piven et al, 1993 / * / * / * / * / * / 5
Juul-Dam et al, 2001 / * / * / * / * / 4
Hultman et al , 2002 / * / * / * / * / ** / * / * / 8
Croen et al, 2005 / * / * / * / * / ** / * / * / 8
Leonard et al, 2006 / * / * / * / * / ** / * / * / 8
Brimacombe et al, 2007 / * / * / * / 3
Buchmayer et al, 2009 / * / * / * / * / ** / * / * / 8
Elhameed, et al, 2011 / * / * / * / * / 4
Krakowiak et al, 2012 / * / * / * / * / ** / * / 7

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(A)Cohort studies

(B)Case-control studies

Supplementary Figure 1. Funnel plot for the associations of maternal diabetes and ASD in the offspring. (A) Cohort studies; (B) Case-control studies.
(A) Cohort studies

(B) Case-control studies

Supplementary Figure 2. Sensitivity analyses by omitting a study at a time. (A) Cohort studies; (B) Case-control studies.

References for the supplementary tables

Brimacombe, M., Ming, X., & Lamendola, M. (2007). Prenatal and birth complications in autism. Matern Child Health J, 11, 73-9

Buchmayer, S., Johansson, S., Johansson, A., Hultman, C.M., Sparen, P., & Cnattingius, S. (2009). Can association between preterm birth and autism be explained by maternal or neonatal morbidity? Pediatrics, 124, e817-25

Burstyn, I., Sithole, F., & Zwaigenbaum, L. (2010). Autism spectrum disorders, maternal characteristics and obstetric complications among singletons born in Alberta, Canada. Chronic Dis Can, 30, 125-34

Croen, L.A., Grether, J.K., Yoshida, C.K., Odouli, R., & Van de Water, J. (2005). Maternal autoimmune diseases, asthma and allergies, and childhood autism spectrum disorders: a case-control study. Arch Pediatr Adolesc Med, 159, 151-7

Dodds, L., Fell, D.B., Shea, S., Armson, B.A., Allen, A.C., & Bryson, S. (2011). The role of prenatal, obstetric and neonatal factors in the development of autism. J Autism Dev Disord, 41, 891-902

Elhameed, M.A.A., Elbaky, A.E.O.A., & Kamel, E.A. (2011). A controlled study of the risk factors and clinical picture of children with autism in an Egyptian sample. Egypt J Neurol Psychiat Neurosurg, 48, 271-276

Hultman, C.M., Sparen, P., & Cnattingius, S. (2002). Perinatal risk factors for infantile autism. Epidemiology, 13, 417-23

Juul-Dam, N., Townsend, J., & Courchesne, E. (2001). Prenatal, perinatal, and neonatal factors in autism, pervasive developmental disorder-not otherwise specified, and the general population. Pediatrics, 107, E63

Krakowiak, P., Walker, C.K., Bremer, A.A., Baker, A.S., Ozonoff, S., Hansen, R.L., & Hertz-Picciotto, I. (2012). Maternal metabolic conditions and risk for autism and other neurodevelopmental disorders. Pediatrics, 129, e1121-8

Leonard, H., de Klerk, N., Bourke, J., & Bower, C. (2006). Maternal health in pregnancy and intellectual disability in the offspring: a population-based study. Ann Epidemiol, 16, 448-54

Lyall, K., Pauls, D.L., Spiegelman, D., Ascherio, A., & Santangelo, S.L. (2012). Pregnancy complications and obstetric suboptimality in association with autism spectrum disorders in children of the Nurses' Health Study II. Autism Res, 5, 21-30

Piven, J., Simon, J., Chase, G.A., Wzorek, M., Landa, R., Gayle, J., & Folstein, S. (1993). The etiology of autism: pre-, peri- and neonatal factors. J Am Acad Child Adolesc Psychiatry, 32, 1256-63

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