A new study now reveals that some preterm babies who are later diagnosed with Autism Spectrum Disorder (ASD) usually show increasing developmental delays during infancy.
The study was designed and conducted by National Cheng Kung University College of Medicine in Taiwan, led by Li-Wen Chen, a pediatric neurologist.
The team followed 319 infants born before 32 weeks of pregnancy from 2008 to 2014 in Taiwan.
They measured the children’s cognitive, language, and motor skills at 6, 12, and 24 months of age. Other data that was collected include parents’ education levels and any complications the children experienced as newborns.
“Children born preterm are at high risk for ASD. However, there is still a lack of appropriate developmental markers,” Chen said at the start of the report.
According to the study, about 7 percent of children born preterm turn out to be autistic, compared to 1 to 2 percent of children in the general population. However, it is difficult to accurately predict which preterm babies are most likely to be later diagnosed with the condition.
The team led by Chen tracked babies born more than 8 weeks prematurely and weighing 3.3 pounds or less, from birth to 5 years.
The study found that preterm autistic babies’ development deviated significantly from that of babies in the general population starting at the age of six months.
In an earlier study, Chen and his team found that autistic children born preterm scored lower on measures of nonverbal behaviors for social interactions than do autistic babies who are born full-term. The same study also found that preterm autistic children share early developmental markers of autism.
There were 29 children with ASD and 290 children without ASD in the study. The study classified the mental performances from the age 6 to 24 months into 3 trajectory patterns: low declining, high declining, and high stable, which corresponded to ASD prevalence at age 5 years of 35 percent, 9 percent, and 3 percent, respectively.
ASD odds were 15 times higher in the low-declining group than in the high-stable group.
Children in the low-declining group tend to be boys and to have received oxygen therapy for a prolonged period at birth.
They are also more likely to have mothers who did not attend college or graduate school.
« Sex is known to play a significant role in outcomes in preterm populations. We recognized that male sex was predictive of the trajectory of poorer mental performance and higher ASD odds. In addition, sex not only influenced the attribution of the mental developmental trajectory, which in turn brought about a distinct ASD risk, but also imposed a direct effect on ASD irrespective of cognitive function. These findings suggest the dual role of sex on ASD risk in children born preterm. »
Margaret Njuguna