Autism, Circadian Disruption and Pregnancy form a triad that deserves closer attention, as emerging evidence suggests that disruptions to the mother’s circadian rhythm during pregnancy may influence the risk of autism spectrum disorders in offspring.
Blue light exposure at night can disrupt the mother’s circadian rhythm — a factor increasingly linked to fetal development and autism spectrum disorders.
Image generated with AI using ChatGPT (OpenAI), input by EMFSA.
A Neglected Risk Factor in Pregnancy
Adverse pregnancy outcomes are commonly linked to factors such as poor nutrition, stress, and environmental toxins. Circadian disruption is now being recognized as another important contributor. Research over the past decade indicates that the circadian system begins developing prenatally through entrainment from the mother.
—Circadian Rhythms as Modulators of Brain Health During Development and Throughout Aging, PMC
How the Fetal Clock Develops — and Why It Matters
The foundation of the circadian system begins forming well before birth. In humans, the brain’s master clock—known as the suprachiasmatic nucleus (SCN)—can be identified by the third trimester. This system is thought to develop in response to maternal signals such as melatonin and daily light-dark cycles. A baby is believed to have a fully functional SCN by around nine months of age.
Research indicates that circadian rhythms influence brain development from early gestation through old age. Disruptions during prenatal development may increase the risk of behavioral and cognitive impairments later in life, while aging is also associated with a natural weakening of these rhythms. Supporting a strong internal clock during pregnancy may therefore be one of the simplest, yet most powerful ways to help protect long-term brain health.
— Circadian Rhythms as Modulators of Brain Health During Development and Throughout Aging, PMC
How Circadian Disruption Occurs in Pregnancy
Epidemiological studies have revealed associations between gestational chronodisruption and adverse pregnancy outcomes. Common sources of circadian disruption during pregnancy include:
- Shift work
- Jet lag from travel across time zones
- Exposure to artificial light at night
— Light and Circadian Signaling Pathway in Pregnancy: Programming of Adult Health and Disease
A Link Worth Investigating Further
The connection between Autism, Circadian Disruption and Pregnancy is becoming more evident as researchers explore how maternal circadian health may shape neurodevelopmental outcomes in the fetus.
Epigenetic Impacts: Altered Placental DNA Methylation
Early-life circadian disruption may increase the risk of chronic illness later in life. Circadian rhythms regulate critical biological processes, including hormone secretion and metabolic function. When disrupted—such as through night shift work—these rhythms can influence the developing fetus in unexpected ways.
One emerging area of concern is the impact on placental DNA methylation.
Clarkson-Townsend et al. (2019) conducted the first study to examine how night shift work, used as a proxy for circadian disruption, may alter methylation patterns in the placenta. Although the findings require cautious interpretation, the study suggests that maternal circadian disruption could lead to epigenetic changes with lasting effects.
Animal studies also indicate that circadian desynchrony in early life can lead to enduring autistic-like behavioral changes in adulthood, reinforcing the potential long-term impact of disrupted rhythms during gestation.
Autism Spectrum Disorders and Neurodevelopment
Autism spectrum disorders include social, communication, and behavioral challenges. Among these are Asperger’s Syndrome and Childhood Disintegrative Disorder. ADHD and autism are both neurodevelopmental conditions that affect brain development and how a person functions day to day. Symptoms typically appear in early childhood and can influence behavior, learning, communication, and emotional regulation throughout life.
— ADHD vs. Autism: The Differences and Similarities
Practical Guidance for Expectant Mothers
Given the potential risks, gynecologists and healthcare professionals should advise pregnant women—and those planning to conceive—to minimize exposure to artificial light at night, especially blue light emitted by phones and screens. Limiting screen use at night is a simple, cost-free measure that may help safeguard fetal circadian development and support healthier neurodevelopmental outcomes.
More on the topic