In Vitro Fertilization May Increase Risk of Autism: Study

The findings of new research indicate that women undergoing in vitro fertilization may be twice as likely to give birth to a child who will later develop autism. 

In a study published online this month in the American Journal of Public Health, researchers from Columbia University identified a link between in vitro fertilization and autism, but indicated that the risk is likely due to multiple births, not the treatment it self.

Nearly 6 million live births were studied, including almost 50,000 using assisted reproduction technology (ART), or in vitro fertilization (IVF).

The observational study focused on records from the California Birth Master Files from 1997 to 2007, the California Department of Developmental Services autism caseload from 1997 to 2011, and the U.S. Centers for Disease Control and Prevention (CDC) National ART Surveillance System for live births from 1997 to 2007.

A total of 33,000 cases of autism were diagnosed by the Department of Developmental Services during that time period. Researchers compared the births that originated using IVF and the births without using IVF.

The study found the rate of autism was twice as high in children conceived using IVF technology, compared to non-IVF conceptions. However, the study concluded the association between autism and IVF diminished by excluding mothers who were unlikely to use IVF. They also adjusted for demographics and adverse prenatal and perinatal outcomes, including multiple births and the mother’s education. This reduced the association substantially.

Autism spectrum disorder is a group of developmental problems that can cause significant social, communication and behavioral challenges. The cause is unknown, but many scientists say environmental, biological and genetic factors likely playing a role in its development.

Currently, the CDC estimates 1 in 68 children in the U.S. is diagnosed with autism.

Autism Risk Linked to Multiple Births

Overall, the researchers found the increase in association between autism and IVF treatment was explained by the rate of multiple births associated with in vitro fertilization and other risks associated with IVF, not the IVF treatment itself.

Researchers contend the increased risk may be explained by other factors related to both IVF and the age of the mother, including pregnancy and labor complications, or complications arising from multiple births.

“The risk of autism appears to be largely modifiable by restricting IVF to single-embryo transfer,” said Peter Bearman, lead author of the study and professor of social sciences at Columbia University in New York City.

The statistical significance was even more apparent for mothers between the age of 20 to 34 years and the risk increased for mothers older than 35.

Assisted reproductive technology includes fertility treatments where both eggs and sperm are handled outside the body. In vitro fertilization occurs in a laboratory setting and is the main type of treatment, according to the CDC.

During IVF, it is common for more than one egg to be harvested and fertilized to give parents a higher chance of conception, this can also lead to multiple births during the same pregnancy. This is what likely causes the risk, not the IVF treatments themselves, the researchers predict.

“Knowing that one can largely reduce the risk of autism by restricting the procedure to single-egg transfer is important for women who can then make better informed decisions,” said Bearman.

There was no significant increased risk of neurodevelopment disorder for children of women who had IVF, but gave birth to only one child. This is the largest study to date concerning the relationship between assisted reproductive technology and autism.