Prematurity refers to birth before 37 weeks of pregnancy. Autism spectrum disorder (ASD) encompasses neurodevelopmental conditions characterized by differences in social interaction, communication, and repetitive behaviors. The potential link between premature birth and autism is a subject of ongoing scientific investigation.
Observed Link Between Prematurity and Autism
Research consistently shows an association between premature birth and an increased likelihood of an autism diagnosis. Infants born very preterm, especially before 27 weeks of gestation, have a higher risk. For example, studies report that approximately 6.1% of infants born extremely preterm (22-27 weeks) were diagnosed with autism, significantly higher than the 1.4% prevalence in full-term births (39-41 weeks).
One biological hypothesis for this association centers on the impact of prematurity on brain development. The third trimester of pregnancy is a period of rapid and complex brain growth, including the formation of white matter and cortical folding. Premature birth interrupts this process, exposing the delicate brain to an external environment different from the womb. This altered environment can lead to changes in cerebellar white matter and affect the organization of cerebral networks, which might contribute to autism-like behaviors.
Understanding the Complexity of Causation
While an association between prematurity and autism is observed, it is important to understand that prematurity is unlikely to be the sole cause of autism. Autism is considered a multifactorial condition, meaning it arises from a combination of genetic predispositions and environmental influences. Genetic factors play a substantial role, with research indicating that common genetic variants can influence early white matter organization in the brain, which is implicated in autism.
Studies attempting to account for various contributing factors have yielded mixed results regarding the direct link between prematurity and autism. Some research, after adjusting for confounding variables such as maternal health, family history of autism, and socioeconomic factors, found no significant direct association between preterm delivery and autism. This suggests that other underlying genetic or environmental factors shared within families might contribute to both preterm birth and autism. However, other large cohort studies have found that the association between preterm birth and increased autism risk persists even after controlling for shared familial factors, suggesting a potential causal relationship.
Importance of Early Developmental Monitoring
Premature infants are at higher risk for various developmental delays and conditions, including autism. Their early arrival means their developing systems, particularly the brain, are more vulnerable to challenges. Therefore, ongoing developmental surveillance and screening are important for premature babies.
The American Academy of Pediatrics recommends general developmental screenings at 9, 18, and 30 months of age, with specific autism spectrum disorder screenings at 18 and 24 months. These screenings help identify any developmental differences or delays early, allowing for timely intervention. While screening at 18 months for very preterm infants can sometimes be inaccurate due to language or cognitive delays, later screening at 30 months has shown improved accuracy in identifying autism.
Available Support and Interventions
For children with developmental delays or an autism diagnosis, early intervention services are available. These services support a child’s development during a period when the brain is highly adaptable, often called “plastic.” Early intervention can significantly improve outcomes by helping children acquire fundamental skills.
Common early intervention services include:
- Developmental therapy, addressing overall developmental progress.
- Speech therapy, focusing on communication skills.
- Occupational therapy, helping with daily living activities and fine motor skills.
- Physical therapy, supporting gross motor development.
- Behavioral interventions, addressing specific behavioral challenges.
These services are typically provided through state-run programs for children from birth to age three who have diagnosed delays or disabilities, or are at risk for them.