The Association Between Maternal Asthma and Child Autism: A Systematic Review and Meta-Analysis.

Maternal asthma has been linked to child autism. In this study, we systematically reviewed observational studies published between July 2001 and February 2024 that assessed maternal asthma during pregnancy (exposure) and child autism (outcome). Databases searched included MEDLINE, CINAHL, EMBASE, and PsycINFO. Of the 350 potential studies, 19 met the inclusion criteria (2,530,716 participants; 73,065 autistic participants). Quality was assessed with the Newcastle-Ottawa Scale. Meta-analyses using proportions and odds ratios were conducted using the Mantel-Haenszel method with a random-effects model. Compared to women without asthma, there was an increased odds of child autism with any history of maternal asthma (OR = 1.32; 95% CI = 1.21, 1.44; I2 = 61%, n = 14), with current asthma during pregnancy (OR = 1.23; 95% CI = 1.12, 1.35; I2 = 35%, n = 10) and with medication use during pregnancy (OR = 1.48; 95% CI = 1.30, 1.68; I2 = 0%, n = 3). However, when women with asthma who used asthma medication were compared to those with asthma who did not use medication, there were no increased odds for child autism (OR = 1.07; 95% CI = 0.89, 1.27; I2 = 34%, n = 2). Maternal asthma is associated with an increased odds of child autism. Future studies should consider neurodivergence in the parents, the severity of asthma, and the effectiveness of prescribed medication in managing the mother's asthma to improve our understanding of this association. Trial Registration: PROSPERO registration: CRD42021265060.