In a study to be presented on Feb. 5 in an oral pleanary session at 8 a.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting in San Diego, researchers will report that induced or augmented labor are not associated with increased odds of Autism spectrum disorder.

Autism spectrum disorder has increased in frequency over the last several decades and now affects one in 68 children in the U.S. Given the observed increase, there has been great interest in identifying potential risk factors. Previous research suggests that environmental factors during pregnancy and childbirth may increase the risk of ASD diagnosis in childhood. One environmental factor of interest is induction and/or augmentation of labor. Labor is induced (started) or augmented (helped along) for many reasons including medical indications and patient preference. Prior research has suggested a potential link between induction/augmentation of labor and ASD.

The study, titled Autism Spectrum Disorder and Induced/Augmented Labor: Epidemiologic Analysis of a Utah Cohort evaluated the association of ASD in a large group of Utah births that occurred between 1998 and 2006. Using data from birth certificates and from a registry of autism cases in Utah (Utah Registry of Autism and Developmental Disabilities), the researchers compared 2,547 children with ASD to 166,283 children without ASD. Children exposed to labor induction and/or augmentation did not have increased odds of ASD after adjusting for important factors such as socioeconomic status, maternal health, pregnancy-related events and conditions, and year of birth. The results were the same for males and females.

"Induction/augmentation of labor is an important strategy to minimize risk to mother and baby in some situations," explained Erin A.S. Clark, M.D. one of the researchers of the study and the person who will present the results at the SMFM annual meeting. "The study reassures both patients and physicians that induction/augmentation of labor does not appear to be associated with autism spectrum disorder risk."

Objective: To evaluate whether induced and/or augmented labor is associated with increased odds of autism spectrum disorder (ASD). Authors: Erin Clark, Deborah Bilder, Michael Varner, M. Esplin, Hilary Coon, Amanda Bakian

Study Design: We performed an epidemiological analysis using data from the Utah Registry of Autism and Developmental Disabilities (URADD) and the Utah Department of Health (UDOH) Vital Records and Statistics. URADD ascertains children with ASD within a four county surveillance area (approximately 70% of the Utah population) by querying records from UDOH, clinics, hospitals and behavioral health centers. Children met the URADD case definition of ASD if they acquired an ASD diagnosis from a qualified health provider such as a developmental pediatrician, child psychiatrist, or clinical psychologist. The resulting study sample was composed of 2219 children identified with ASD (case group) and 166,361 children without ASD (control group) belonging to the 1998, 2000, 2002, 2004, and 2006 birth cohorts ascertained by URADD. Birth certificates contained exposure to labor induction and/or augmentation as well as known ASD risk factors, which were treated as confounders in this analysis. Differences in characteristics between cases and controls, by sex, were examined using chi-square goodness-of-fit tests. Multiple logistic regression models examined the probability of being an ASD case or control as related to labor induction and/or augmentation adjusting for confounders.

Results: Approximately 1 in 75 children in the cohort had ASD (1.3%). Compared with children not exposed to labor induction and/or augmentation, children exposed to induction and augmentation, induction only, or augmentation only, did not have increased odds of ASD after controlling for potential confounders related to socioeconomic status, maternal health, pregnancy-related events and conditions, and birth cohort. A sex-stratified analysis yielded similar results. (Table)

Conclusion: Induction and/or augmentation during childbirth are not associated with increased odds of ASD in childhood in a large Utah cohort.