Pregnancy-related maternal risk factors of attention-deficit hyperactivity disorder: a case-control study.

Background. The etiology of attention-deficit hyperactivity disorder (ADHD) is complex.This study was conducted to evaluate the pregnancy-related maternal risk factors of ADHD. Methods. 164 ADHD children attending to Child and Adolescent Psychiatric Clinics compared with 166 normal children selected in a random-cluster method from primary schools. ADHD rating scale and clinical interview based on Schedule for Affective disorders and Schizophrenia for School-Aged Children (K-SADS) were used to diagnose ADHD cases and to select the control group. Results. The mean maternal age at pregnancy, duration of pregnancy, and the mean paternal age were alike in two groups. The ADHD children's mothers compared with those of control group had higher frequencies of somatic diseases, psychiatric disorders, and alcohol and cigarette exposure during the pregnancies (P < 0.01). Also birth by cesarean section was more common among mothers of ADHD children (P < 0.001). These factors plus trauma to the abdomen during pregnancy were significantly predictors of ADHD in children. Conclusions. Some pregnancy-related maternal factors may be considered as environmental risk factors for ADHD. Each of these factors considered in our study as a risk factor needs to be tested and confirmed through next methodologically appropriate researches in this field.