What Raises a Baby's Risk of Autism?
Study Flags Possible Associations From Parents, Pregnancy, Birth
May 18, 2005 -- Pregnancy factors, parental psychiatric history, and
preterm delivery may be associated with an increased risk of says a study in the
American Journal of Epidemiology.
Here are the potential associations noted in the study:
- Breech presentation of the baby
- Low Apgar score, an index used to evaluate the condition of a newborn five
minutes after birth
- Birth before 35 weeks of pregnancy
- Parental history of schizophrenia-like psychosis
- Parental history of affective disorder, which includes some psychoses, depression, and bipolar disorder
However, those traits are not presented as definite causes
of autism or as the only possible risk factors for the condition. Of
course, not all babies born under those circumstances have autism or related
'Possible Associations' Noted
"Right now, we have only
" says CDC epidemiologist Diana Schendel, PhD, in a
news release. "But if we can find a cause-and-effect relationship, it may
help our efforts to prevent autism." Schendel worked on the study with
It's not known how those characteristics might interact with autism
spectrum disorders are a group of developmental disabilities that are
caused by unusual brain development, says the CDC's Autism Information Center.
Some studies have shown that a of
The spectrum includes autistic disorder (infantile autism), pervasive
developmental disorder, and
People with autism spectrum disorders tend to have problems with social and
communication skills, and many have unusual ways of learning, paying attention,
or reacting to different sensations, says the CDC.
The cause of autism spectrum disorders is not known. Studies on twins and
families suggest that genetics may play a substantial role, the new study
The study says between two and six per 1,000 children have autistic spectrum
disorder, while autism specifically affects up to two per 1,000 children.
More children than ever before are classified with autism spectrum
disorders. It's not clear if that's due to
says the CDC.
The study focused on autistic disorder (autism), not other conditions in the
autism family. Data came from Denmark's national health care system, which has
records on virtually all children diagnosed with autism.
The study included every autistic child born in Denmark in the last 32 years
and diagnosed before 2000. Each of the nearly 700 autistic children was
compared with 25 kids without autism.
Parental psychiatric histories prior to the child's diagnosis of autism had
the highest association with autism, says the study. Taking all the risks into
account, parental psychiatric history increases the risk of an autism
diagnosis by three- to fourfold. The authors do note that there have been
genetic links found between schizoid personality traits and autism.
Autism was not associated with infant weight, number of previous babies born to the mother,
number of doctor visits before pregnancy, parental age, or socioeconomic