Results of a new study suggest that children born to individuals with infertility challenges may have a slightly higher risk of receiving an autism spectrum disorder (ASD) diagnosis.
The number of children diagnosed with autism spectrum disorder (ASD) continues to rise worldwide. For example, in the United States, CDC surveillance data indicated that one in 68 children had autism in 2010. However, in 2020, that number has increased to one in 36 children.
Despite the increase in prevalence, scientists still haven't identified what causes autism. Research has revealed that genetics, environmental factors such as insecticide exposure, and childhood infections may play a role. In addition, scientists have found links between autism and the gut biome.
Previous research also suggests that children conceived using assisted reproductive technology may be more likely to develop ASD.
Now, research published on November 20 in Pediatrics found that children born to individuals who have experienced infertility were more likely to have autism, but fertility treatments did not appear to be a factor.
Investigating infertility and autism
The cohort study involved 1.3 million children born in Ontario, Canada, between 2006 and 2018. The scientists compared babies born to individuals without infertility and those who experienced infertility but did not undergo fertility treatments. They also looked at children conceived via ovulation induction (OI), intrauterine insemination (IUI), in vitro fertilization (IVF), or intracytoplasmic sperm injection (ICSI).
The research team followed the children for an average of eight years.
During the study period, 22,409 children received an autism diagnosis. After calculating ASD risk using person-years measurements, the team found that the ASD incidence rate was 1.9 per 1,000 person-years among children born to individuals without fertility challenges, 2.5 per 1,000 person-years among children born to people with infertility issues, and 2.7 per 1,000 person-years among youngsters conceived via fertility treatments.
The study's authors say children born to individuals with infertility who did not undergo infertility treatment had similar autism risks, meaning infertility itself, not its treatments, may drive the increased chance of ASD.
However, the scientists say adverse pregnancy outcomes may also play a role in autism risks. They also note that individuals with fertility challenges in the study were older and had higher rates of diabetes and high blood pressure before pregnancy.
Lead investigator Maria P. Velez, M.D., Ph.D., a clinician scientist at Queen's University, Ontario, Canada, said, "Our results also show that some obstetrical factors, like having twins or triplets, or giving birth preterm, mediate a large proportion of the association between parental infertility and ASD."
Because of their findings, the research team says more effective strategies are needed to lessen adverse pregnancy outcomes in people experiencing infertility.
In addition, the mechanisms behind the associations between infertility and autism need further investigation.
"For example," Velez explained, "we need more granular details about the baseline infertility diagnosis, paternal factors, and whether the oocyte (egg) or sperm are from the parent or a donor, among other factors."