A new analysis of medical records suggests that the induction and augmentation of labor is associated with a modestly increased risk that a child will develop autism. The study, in JAMA Pediatrics, is the largest to date on this issue.
Researchers with Duke University and the University of Michigan matched the medical records of more than 625,000 births with school records indicating later diagnosis of autism. Among boys, birth involving both induced and augmented labor was associated with a 35 percent higher occurrence of autism compared with labor that received neither treatment.
Separately, induced or augmented labor was associated with a smaller increased risk among boys. Among girls, only augmented birth was associated with a small increased risk. In their analysis, the researchers controlled for several associated factors previously shown to increase autism risk. These included the health and age of the mother.
The findings do not prove cause and effect, the researchers hasten to add. Other, unidentified factors could be at play.
“Over the last decade or so, it’s become clear that a combination of genetic and environmental risk factors contribute to risk for autism,” comments Alycia Halladay, senior director of environmental and clinical sciences at Autism Speaks. “Clearly more research is needed before these results should be used to inform clinical practice,” Dr. Halladay adds. "The next step will be to understand why there is this association.”
A Pitocin Connection?
One possible explanation is the use of oxytocin medication (trade name Pitocin) to induce or augment labor. An estimated 50 to 70 percent of women undergoing labor induction receive oxytocin injections in the United States. Other contributors might include pregnancy conditions and delivery events associated with the need to induce or augment labor.
Earlier, smaller studies have suggested that the administration of oxytocin to induce or augment labor could contribute to the development of autism. (See “Autism-Pitocin Connection?” in the Autism Speaks “Got Questions?” blog.)
“However, these studies produced conflicting results and consisted of a relatively small number of subjects,” says the new study’s lead author Simon Gregory. Dr. Gregory is an associate professor of medicine and medical genetics at Duke. “Our study is by far the largest of its kind to look at the association between autism and induction or augmentation.”
The study authors call for further study – with urgency given that labor induction and augmentation have become increasingly frequent practices.
Experts agree, however, that expediting deliveries can be crucial to the health of both women and their babies. Inducing labor involves stimulating contractions before the onset of natural labor. Augmenting labor involves increasing the strength, duration or frequency of contractions after labor has begun. When used appropriately, both have been shown to prevent complications, including stillbirth.
Michael Rosanoff, associate director for public health research and scientific review for Autism Speaks, discussed the study on CBS News Up to the Minute and CTV News. Watch the CBS News story below and click here for CTV News.