Key Findings: The association between assisted reproductive technology and autism spectrum disorder
Researchers have published new studies looking at the relationship between assisted reproductive technology (ART) and autism spectrum disorder (ASD) among a group of children born in California between 1997 and 2007. The key findings from each study are highlighted below. These findings are important for researchers, healthcare providers, and public health professionals as we strive to better understand what factors put children at risk for ASD.
Does assisted reproductive technology increase the risk for autism spectrum disorder1?
- Overall, children conceived using ART were about two times more likely to be diagnosed with ASD compared to children conceived without using ART.
- Evidence suggests that for pregnancies conceived with ART, the increased risk for ASD is, in large part, due to the higher likelihood of adverse pregnancy and delivery outcomes. In other words, using ART may lead to factors that are known to put children at risk for ASD, such as being born a twin or multiple (triplets, quadruplets, etc.), being born too early, or being born too small.
- More research is needed to explore what exactly underlies the observed relationship between ART and ASD.
- However, these findings suggest that single embryo transfer, where appropriate, may reduce the risk of ASD among children conceived using ART.
Does type of ART procedure impact the relationship between assisted reproductive technology and autism spectrum disorder2?
- Among children conceived using ART, about 0.8% of those born as singletons (only one baby carried during the pregnancy) and about 1.2% of those born as a twin or multiple were diagnosed with ASD.
- Children conceived using ART were more likely to be diagnosed with ASD if intracytoplasmic sperm injectionExternal (ICSI) was used compared to conventional in vitro fertilizationExternal. ICSI and in vitro fertilization are procedures in which fertilization (a sperm entering an egg) occurs outside of the body; ICSI occurs by injecting a sperm directly into an egg while in vitro fertilization involves mixing sperm with eggs in a laboratory dish and allowing fertilization to occur.
- More research is needed to explore what exactly underlies the observed relationship between ICSI and ASD.
Does autism diagnosis age or symptom severity differ among children according to whether ART was used to achieve pregnancy?3
- Among children receiving services for autism, children who had been conceived using ART had a lower median age of autism diagnosis (3.3 years) than those who were not conceived using ART (4.0 years).
- Despite being identified earlier, the children who had been conceived using ART were less likely to have co-occurring intellectual disability or to be classified as having the most severe deficits in communication and social functioning than children who were not conceived using ART.
- The differences in autism diagnosis age were largely accounted for by socio-demographic differences between ART-conceived and non-ART-conceived children, and the differences in autism symptom severity were entirely accounted for by socio-demographic differences between the groups.
- These findings indicate that earlier identification of autism in children who come from more advantaged families and exhibit less severe autism symptoms contributes to the ART-autism association observed in the overall population. This is likely due to more advantaged families having greater access to ART services.
More About These Studies
These studies used one of the largest population-based datasets on ART. Specifically, these studies examined data obtained from three sources: the California Birth Master Files, the California Department of Developmental Services autism caseload records, and CDC’s National ART Surveillance System. These datasets included a total of almost 6 million births, including almost 50,000 children conceived through ART. A key advantage of this study is its large size, which provides more confidence in the results than previous studies that looked at relationships between ART and ASD.
- To learn more about assisted reproductive technology and CDC’s work on this issue, please visit www.cdc.gov/ART.
- To learn more about autism spectrum disorder and CDC’s work on this issue, please visit www.cdc.gov/Autism.
- Fountain C, Zhang Y, Kissin DM, Schieve LA, Jamieson DJ, Rice C, Bearman P. Association between ART conception and autism in California 1997-2007. American Journal of Public Health. March 2015. [epub ahead of print]
- Kissin DM, Zhang Y, Boulet SL, Fountain C, Bearman P, Schieve L, Yeargin-Allsopp M, Jamieson DJ. Association of assisted reproductive technology (ART) treatment and parental infertility diagnosis with autism in ART-conceived children.External Human Reproduction. 2015 Feb;30(2):454-65.
- Schieve LA, Fountain C, Boulet SL, Yeargin-Allsopp M, Kissin DM, Jamieson DJ, Rice C, Bearman P. Does autism diagnosis age or symptom severity differ among children according to whether assisted reproductive technology was used to achieve pregnancy? Journal of Autism & Developmental Disorders 2015 Sept; 45(9): 2991-3003.