• At least 1 in 6 pregnant people in Michigan use cannabis, with a higher likelihood among ‘socially disadvantaged populations’
• Cannabis use during pregnancy carries significant health risks including low birth weight
• Medical experts warn that legalization has outpaced public health messaging about the risks associated with cannabis

At least one in six pregnant mothers in Michigan are using cannabis, according to researchers at Michigan State University. 

Their findings, recently published in the journal Addiction, indicate “socially disadvantaged populations” in the state are more likely to use marijuana during pregnancy — a concerning trend for doctors who highlight the adverse outcomes in developing babies and infants exposed to cannabis.

Ban Al-Sahab, the epidemiologist who led the study, researches child and maternal health at MSU. She has focused on examining cannabis use during the prenatal period after Michigan lifted prohibitions on recreational marijuana use in 2018. 

“With legalization, cannabis becomes more affordable, accessible, perceived as safe … we were really interested in understanding the scope of this problem,” Al-Sahab told Bridge Michigan.

The research, which is part of a broader study following child development in Michigan over the course of several years, surveyed expecting mothers at different points in their pregnancy to understand their cannabis use. In addition to self-reporting, researchers also took urine samples to test for THC, a psychoactive compound found in cannabis.

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“Women are less likely to report cannabis use due to stigma, social desirability bias, fear of legal consequences, CPS (Children’s Protective Services) involvement,” Al-Sahab explained of the methodology.

Al-Sahab said researchers looked into various demographic factors, landing on four that were the most associated with increased cannabis use — marital status, education, depressive symptoms and adverse childhood experiences.

“We saw that unmarried women were twice more likely to use cannabis during pregnancy than married women,” she said. “Women who had lower educational attainment were more likely also to use cannabis during pregnancy.”

Some pregnant people may be inclined to use cannabis to “self medicate” depression or anxiety, Al-Sahab said. Adverse childhood experiences like abuse, trauma, deaths in the family or housing instability have been associated with an increased likelihood of mental health disorders and substance abuse problems.

Dr. Cara Poland, an addiction medicine specialist who runs MSU’s Addiction Consortium on Research & Education Network, said the study’s findings are a “call to action.”

“Legalization has outpaced our public health messaging, and this perception that cannabis is safe and doesn’t have consequences … is not accurate,” Poland told Bridge. “While cannabis may not carry the same kind of acute toxicity and withdrawal risks as opioids or alcohol, there are real perinatal risks that have been well documented.” 

Cannabis use increases risk for low birth weight, pre-term delivery and neonatal intensive care unit admissions, Poland said, and several studies indicate marijuana can cause developmental delays and other negative outcomes in young children. Maternal health outcomes can also be adversely affected by marijuana use during pregnancy, including high blood pressure and preeclampsia.

Poland said “one in 10 people that uses cannabis struggles with discontinuing,” and marijuana withdrawal syndrome can lead to nausea and vomiting when people stop daily use. Those symptoms are commonly associated with early pregnancy, complicating patients’ perception of how cannabis affects their bodies.

“It’s actually more likely that it’s the cannabis that’s causing the nausea and vomiting, and not actually morning sickness,” Poland said.
Clinical guidance from the the American College of Obstetricians & Gynecologists instructs doctors to educate patients that there are no medical reasons to use cannabis during pregnancy and the postpartum period.