Mental illness and substance use during pregnancy may lead to adverse maternal and birth outcomes, and recent research highlights concerning trends for both risk factors. Based on analysis of 2012-2021 National Survey on Drug Use and Health data, the prevalence of any mental illness (AMI) and serious mental illness (SMI) among pregnant individuals has increased over the past decade, and the use of two or more substances (tobacco, alcohol or marijuana) has increased disproportionately among those with SMI. The researchers suggest compassionate, tailored strategies to best serve pregnant individuals with co-occurring mental illness and substance use. To learn more, see the study in Psychiatry Research.