Kids who are conceived during winter have an increased risk of autism, found in a study.
An examination of the birth records of the more than 7million children born in the state of California during the 1990s and early 2000s has found a clear link between the month in which a child is conceived and the risk of that child later receiving a diagnosis of autism.
The risk of having a child with an autism spectrum disorder grew progressively throughout the fall and winter to early spring, with children conceived in March having a 16 percent greater risk of later autism diagnoses, when compared with July conceptions.
The researchers said the finding suggested that environmental factors, for example, exposure to seasonal viruses like influenza, might play a role in the greater risk they found of children conceived during the winter having autism.
"The study finding was pronounced even after adjusting for factors such as maternal education, race /ethnicity, and the child's year of conception," said lead study author Ousseny Zerbo, a fifth-year doctoral student in the graduate group in epidemiology in the Department of Public Health Sciences in the UC Davis School of Medicine.
The study has been published in the journal Epidemiology.