At least 1 in 6 pregnant Michigan women uses cannabis

New research from Michigan State University found cannabis exposure occurs in at least one in six pregnancies in Michigan and as high as one in four in some parts of the state.

Michigan legalized medical cannabis in 2008 and adult recreational use in 2018, becoming the first Midwestern state to do so. The American College of Obstetricians and Gynecologists recommends against cannabis use during pregnancy and while breastfeeding.

“With increased legalization, cannabis becomes more accessible, affordable and perceived as safe,” said lead researcher Ban Al-Sahab, assistant professor in the Department of Family Medicine in the College of Human Medicine. “This changing legal and social landscape around cannabis necessitates a deeper understanding of trends and characteristics associated with cannabis use. Our research provides timely validated measures of its use in pregnant populations.”

The research, published in Addiction, used self-reported data and urine toxicology testing to measure cannabis use. The data came from a prospective statewide pregnancy cohort, the Michigan Archive for Research on Child Health, or MARCH, that is part of the Environmental influences on Child Health Outcomes, or ECHO, program—one of the largest studies funded by the National Institutes of Health.

The cohort enrolled a representative sample of pregnant Michigan mothers between 2017 and 2023, which consisted of just over 1,100 people who were recruited at their first prenatal visit.

“The unique contribution of this study is that it estimates the statewide prevalence of prenatal cannabis use using both self-reported data and urine toxicology, providing findings that are generalizable to the pregnant population of the entire state,” said Al-Sahab. “Our sampling design enables us to produce estimates that are representative of all births in the state of Michigan.”

A related study using MARCH data found that around one-third of those who used cannabis during pregnancy did not disclose use. Many pregnant women choose not to disclose cannabis use due to the social stigma that surrounds drug use, fear of discrimination based on race or socioeconomic status, and fear of potential legal implications. 

“Our findings underscore the urgent need to better understand why cannabis use is so prevalent during pregnancy and how to support women in making safe choices for themselves and their babies,” said Al-Sahab. “Moving forward, our goal is to develop new interventions that aim to curb the prevalence of cannabis use and improve maternal and infant health outcomes.”  

The study was funded by the Office of Research on Women’s Health at the National Institutes of Health and the Addiction Consortium on Research and Education Network at Michigan State University.