METHODS：The study included 418 consecutive Japanese children with ASD who visited the pediatric developmental clinic at Osaka University Hospital. Questionnaires were used to obtain perinatal information. The questionnaires were completed by caregivers at their first visit. We analyzed the incidence of perinatal abnormalities in children with ASD and compared it with that obtained from population-based statistical data.
RESULTS：The incidence of low birth weight（15.4%）was 2-fold higher in ASD children compared to that reported in a Japanese population-based statistic report for maternal and child health. In addition, the incidence of birth after assisted reproductive technology（13.7%）was 7-fold higher compared to that reported in the general population in a national survey conducted by the Japan Society of Obstetrics and Gynecology. Among the autistic symptoms, aggressive behavior was significantly associated with abnormalities during pregnancy, while restricted interest, impulsiveness, gaze abnormality, self-injury, and sleep disorders were significantly associated with abnormalities during the neonatal period. Despite a neonatal follow-up, 5 extremely premature infants were diagnosed with ASD at a late mean age of 6 years and 2 months. The initiation of intervention and diagnosis for ASD were the same regardless of the perinatal abnormality.
CONCLUSIONS：In this study, the employment of assisted reproductive technology and perinatal abnormalities, including low birth weight, were identified as risk factors for ASD. These findings are similar to those reported in previous foreign studies. Furthermore, our data suggest that the timing of the perinatal insult may affect autistic symptoms. We believe that it is crucial to establish a system for identifying developmental disorders as early as possible in children with perinatal abnormalities.
