The prenatal environment can exert important effects on mental health. While much research has linked low birth weight to psychopathology, the intrauterine environment associated with high birth weight (macrosomia; > 4000 g) is also sub-optimal and may increase risk. Given the increasing prevalence of macrosomic births, understanding the mental health outcomes of infants born macrosomic can help refine theories of etiology, predict disorder, and target preventive interventions. Using data from the 2014 Ontario Child Health Study (OCHS), we examined the risk for psychiatric disorders in adolescents born macrosomic. Youth (N = 2151) aged 12-17 years completed the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID). Rates of common mental disorders assessed by the MINI-KID were compared between those born at normal birth weight (NBW; 2500-4000 g, n = 1817) and adolescents born macrosomic (> 4000 g, n = 334). These associations were then adjusted for participant age, sex, socioeconomic status (SES) of the family, parental mental health, and gestational diabetes mellitus. After adjustment for covariates, adolescents born macrosomic had higher odds of conduct disorder (CD; OR = 3.19, 95% CI: 1.37-7.43), oppositional defiant disorder (ODD; OR = 1.79, 95% CI: 1.11-2.91), and ADHD (OR = 1.77, 95% CI: 1.21-2.80). Moderation analyses revealed that males born macrosomic were more likely to have psychiatric problems than their female peers. Socioeconomic disadvantage also amplified the risk posed by macrosomia for ODD, ADHD, major depressive disorder, and generalized anxiety disorder. In this study, macrosomia was associated with an increased risk of clinically significant externalizing problems in adolescence, most notably among boys and those facing socioeconomic disadvantage.
Keywords: Early life stress; Fetal macrosomia; Mental disorders; Sex.