According to the World Health Organization, autism spectrum disorder (ASD) affects approximately 10% of children globally. ASD is theorised to be caused by a combination of genetic and environmental factors, including maternal asthma. Maternal asthma, defined as asthma existing in mothers prior to childbirth, is thought to cause ASD by altering the mothers’ immune response, which then changes the levels of hormones required for foetal brain development. Previous studies have shown an association between asthma in mothers and ASD development in their children, however these results had yet to be validated by a meta-analysis. In research published in July 2025 in Nature, Jingfang Zheng and colleagues conducted a meta-analysis study that measured the association between having an asthmatic mother and ASD development. The study found that children of asthmatic mothers had a 36% increased odds of developing ASD compared to children of asthma-free mothers.
To observe the effects of maternal asthma and odds of children developing ASD, this study conducted a meta-analysis using electronic databases (PubMed, Web of Science, Embase, and the Cochrane Library), covering studies published from the inception of the databases to October 2024. Studies were included in the meta-analysis if mothers in the exposed group were asthmatic, mothers in the control group were asthma-free, the outcome was a prevalence of ASD in the mothers’ children, and if the study design was either a case-control or a cohort study. From the selection process, eight studies were selected (five in the US, one in Sweden, one multicentre, and one in Taiwan and mainland China). Additionally, subgroup analysis by the child’s sex was carried out using a meta-analysis of two studies (both US-based). The joint sample size of the eight studies was 152,697 participants with maternal asthma and 1,809,488 without maternal asthma. Children of asthmatic mothers had a 36% increased odds of developing ASD compared to children of asthma-free mothers. The effects of maternal asthma on ASD development differed based on the child’s sex, with only male children of asthmatic mothers being observed to have a statistically significant increased odds of ASD development, with a 28% increased odds of developing ASD, compared to those with asthma-free mothers.
This study by Zheng and colleagues provides evidence of maternal asthma being a risk factor for ASD in children, and that this risk is especially pronounced for male children. However, the certainty of these trends was classified as low, due to the study design and variation in results across the studies. Therefore, more studies assessing the relationship between maternal asthma and ASD risk are required to validate these findings. GlobalData epidemiologists forecast that in the 16 major markets: (the US, France, Germany, Italy, Spain, the UK, Japan, China, Australia, Brazil, Canada, India, Mexico, Russia, South Africa, and South Korea), diagnosed prevalent cases of ASD in men of all ages will decrease from 5.9 million cases in 2025 to 5.7 million cases in 2031, and cases in women of all ages will decrease from two million cases in 2025 to 1.9 million cases in 2031.