MedicalResearch.com: What are the main findings of the study?
Prof. Silva: Our study is one of the largest population based studies of 12,991 children with ADHD. We found that smoking in pregnancy, maternal urinary infections, preeclampsia, being induced and threatened pre-term labour increases the risk of ADHD with little gender differences. Prematurity also increased the risk of ADHD including babies born late preterm and early term marginally increased the risk of ADHD.
MedicalResearch.com: Were any of the findings unexpected?
Prof. Silva: Oxytocin augmentation of labour appears protective for girls which is an unexpected finding and warrants further research. Oxytocin has recently received more interest in the literature, especially its role in social behaviour, although there still remain a number of unanswered questions about plausible mechanisms and actions. Contrary to other studies we found no increased risk for low birth weight, being born post term and low Apgar scores including fetal distress. The rare cord prolapse had nearly a three- fold increased risk of ADHD in females only.
MedicalResearch.com: What should clinicians and patients take away from your report?
Prof. Silva: There is a genetic predisposition to ADHD, as well as some evidence of environmental factors playing a part. Maternal smoking in pregnancy increased the risk of ADHD in their offspring. Females should be advised not to smoke in pregnancy. Attention to inflammatory processes like preeclampsia and urinary tract infections. Early inductions for no obstetric reason should be discouraged.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Prof. Silva: Future research on the risk of early inflammatory processes on ADHD which also include the early post natal period. Studies designed to disentangle possible mechanisms, confounders and/or moderators of these risk factors are warranted.