International Meeting for Autism Research: Pregnancy Complications and Obstetric Suboptimality as Risk Factors for Autism Spectrum Disorders in Children of the Nurses' Health Study II

Pregnancy Complications and Obstetric Suboptimality as Risk Factors for Autism Spectrum Disorders in Children of the Nurses' Health Study II

Saturday, May 22, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)
10:00 AM
K. Lyall , Epidemiology, Harvard School of Public Health, Boston, MA
D. L. Pauls , Massachusetts General Hospital, Boston, MA
D. Spiegelman , Epidemiology, Harvard School of Public Health, Boston, MA
A. Ascherio , Epidemiology, Harvard School of Public Health, Boston, MA
S. L. Santangelo , Center for Human Genetic Research, Psychiatric & Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Boston, MA
Background: The results of numerous studies suggest pregnancy and obstetric complications may be associated with autism spectrum disorders (ASD). However, it is unclear whether certain individual complications confer a higher risk than others, or whether associations differ by diagnostic subgroup. Further, the mechanisms underlying such associations are unknown.

Objectives: To examine specific pregnancy and obstetric complications in association with risk of autism spectrum disorders as a group and by diagnostic subgroup in a large United States cohort.

Methods: Participants from the Nurses’ Health Study II, a prospective national cohort with reproductive, medical, and health information collected through biennial mailed questionnaires since 1989 and information on autism spectrum disorders collected in 2005. Logistic regression was used to obtain crude and adjusted odds ratios for ASD, and by diagnostic sub-group (autism, Asperger syndrome, or other ASD).

Results: 793 cases occurred among 66,445 pregnancies. Overall, pregnancy and obstetric complications were positively associated with risk of ASD (OR 1.49, 95% CI 1.26, 1.77, p <.0001  for pregnancy complications and 2.76, 95% CI 2.04, 3.74, p <.0001  comparing individuals with 4 or more obstetric suboptimality factors to those with none). Associations were similar by diagnostic subgroup. In particular, gestational diabetes was consistently associated with a significantly increased risk of ASD whether considering results in primary or sensitivity analyses or by diagnostic subgroup (OR in primary analysis = 1.76, 95% CI 1.34, 2.32, p <.0001). Sub-optimal parity and sub-optimal age at first birth were also individual factors associated with ASD.

Conclusions:

Consistent with previous research, general pregnancy complications were associated with autism spectrum disorders as a whole. Additional work will be required to more fully assess the role of gestational diabetes.

See more of: Epidemiology
See more of: Clinical & Genetic Studies