Maternal infection during pregnancy and the risk of attention-deficit/hyperactivity disorder in the offspring: A systematic review and meta-analysis

The effects of maternal infection during pregnancy on the risk of attention-deficit/hyperactivity disorder (ADHD) in the offspring are unclear, and no overview is available. We searched the PubMed and EMBASE databases for relevant studies and performed a systematic review and meta-analysis of the literature. We found that that maternal infection during pregnancy was associated with a small increase in the risk of ADHD (OR 1.25, 95% CI 1.09, 1.44, P < 0.0001; I2 = 92.9%, p < 0.0001) in the offspring. In subgroup analyses, the association remained for maternal genitourinary (GU) infection (OR, 1.19, 1.12, 1.27, P < 0.001; I2 = 0%; p = 0.517). However, there was no significant association when we pooled data from siblings from other pregnancies (OR = 1.06, 95% CI, 0.99–1.13, P = 0.084; I2 = 0%; p = 0.859), implying that the association was due to confounding. The statistically significant association between maternal infection during pregnancy and ADHD in the offspring can be partially explained by unmeasured confounding.