Pregnancies that are spaced closer together may have an increased autism risk, according to a recent data review of past studies involving more than 1.1 million children.
Research author Dr. Agustin Conde-Agudelo of the World Health Organization Collaborating Center in Human Reproduction at the University of Valle in the U.S.Conde-Agudelo and his team reviewed seven large studies on autism.
The result of their review showed that children born to women with pregnancies spaced less than 12 months apart were twice as likely to develop autism compared to pregnancies with a three-year or more gap. A wider pregnancy spacing gap of more than five years, on the other hand, also increased the risk for milder autism types like Asperger’s syndrome and pervasive developmental disorder.
“Based on the current best available evidence, it appears that the ideal interpregnancy interval--the time elapsed between the birth of the immediate older sibling and the conception of the younger sibling--is two to five years in order to reduce the risk of autism,” says research author Dr. Agustin Conde-Agudelo of the World Health Organization Collaborating Center in Human Reproduction at the University of Valle in the U.S.
The scientists stress, however, that their research merely points to an "association," and does not prove that short or long intervals between pregnancies can cause autism. “The reasons for the association between short interpregnancy intervals and autism and other neurodevelopmental disabilities are unknown,” says Conde-Agudelo.
The study was published in the journal Pediatrics.
Autism and other neurodevelopmental disorders are thought to be caused by a complex mix of several factors including genetics, environment, parental health and behaviors during pregnancy, and complications during birth, according to the researchers.
Signs of an autism spectrum disorder (ASD) are already present before the age of three but most are diagnosed at the age of four. It’s a condition that affects social interaction, communication, interests and behavior. Children with ASD typically have cognitive, learning, emotional and behavioral problems.
According to the World Health Organization recommendation, children should be spaced at least two years apart for both the mother and child’s optimum health. This recommendation is based on studies that associate pregnancy interval with the risk of low birth weight babies and pre-term delivery.
In an article on Smartparenting.com.ph, Mary Faith Angat, M.D., OB-gyn at Cardinal Santos Medical Center and Taytay Doctors Multispecialty Hospital, eases worrying moms, “If you get pregnant less than 12 months after giving birth, it doesn’t necessarily mean there would be problems. It just means that there are things you and your doctor need to be aware of so you can enjoy a safe and healthy pregnancy.”