A new study published in Addiction reveals a concerning trend: cannabis use among pregnant women in teh United States has considerably increased in recent years, rising from 2.4% in 2002 to 7% in 2017. This increase coincides with shifting public perception regarding the drug’s safety-a belief researchers say is increasingly at odds with emerging scientific evidence. The findings, based on data from over 1,100 first-time mothers in Michigan, underscore the urgent need for greater awareness of potential risks to both maternal and fetal health.
Studies published in the scientific journal Addiction reveal a significant increase in cannabis use among pregnant women in the United States, raising concerns about potential impacts on both maternal and fetal health. This trend underscores the need for increased awareness and research into the effects of cannabis during pregnancy.
Researchers, led by Ban Al-Sahab, PhD, a public health scientist and epidemiologist at the Department of Family Medicine at Michigan State University, found that self-reported cannabis use among expectant mothers rose from 2.4% in 2002 to 7% in 2017. This increase coincides with a growing perception that the drug is harmless, a belief that the study challenges.
The research indicates a shift in attitudes toward cannabis safety. In 2005, 25.8% of pregnant women who had used cannabis in the past month believed it posed no harm. By 2015, that number had jumped to 65.4%. [2] This change in perception is particularly concerning given that the potency of cannabis has steadily increased over the same period.
The study, based on data from 1,105 first-time mothers across 20 clinics in Michigan, revealed that 16.8%—or about one in six—had recently used cannabis. Researchers utilized both self-reporting and urine samples to assess cannabis use, recognizing that previous studies have shown pregnant individuals often underreport their consumption.
This approach was validated by comparing self-reported data with urine tests. Previous research in California, for example, showed that urine tests revealed twice the number of pregnant individuals using cannabis compared to self-reports between 2009 and 2017. A similar disparity was observed in Colorado in 2016, where 6% of new mothers reported recent cannabis use, while 22.4% tested positive in umbilical cord blood samples.
Growing evidence demonstrates the potential harms of cannabis exposure during fetal development. THC, the psychoactive component of cannabis, crosses the placenta and has been linked to preterm birth and lower birth weight. [3] Children exposed to cannabis prenatally may also face an increased risk of developing attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder, and other neurodevelopmental conditions.
The study also found that cannabis use was twice as common among single women compared to those in relationships, and nearly four times more prevalent among individuals without post-secondary education. Additionally, pregnant women experiencing depression were twice as likely to use cannabis.
Researchers suggest several factors contribute to the increasing rates of cannabis use during pregnancy. These include the widespread belief that the drug is harmless—even with weekly use—its increasing affordability and accessibility, and its perceived ability to alleviate stress and anxiety. Michigan legalized medical marijuana in 2008 and recreational use in 2018, leading to lower prices and easier access.
The findings from Al-Sahab and her team, published in Addiction, highlight the need for further research and public health initiatives to educate pregnant women about the potential risks of cannabis use. [1] The study also notes that mothers who use cannabis may have a slightly increased risk of complications such as high blood pressure and preeclampsia.
References:
[1] Al-Sahab et al (2025). Prevalence and characteristics of prenatal cannabis use in Michigan, USA: A statewide population‐based pregnancy cohort. Addiction, 121(1), 126–137. – Al‐Sahab – 2026 – Wiley Online Library
[2] Jarlenski et al (2017). Trends in perception of risk of regular marijuana use among US pregnant and nonpregnant reproductive-aged women. American Journal of Obstetrics & Gynecology. Research Letter. Volume 217, Issue 6
[3] Young-Wolff et al (2024). Prenatal Cannabis Use and Maternal Pregnancy Outcomes, JAMA Internal Medicine Vol. 184, No. 9. | Substance Use and Addiction Medicine | JAMA Internal Medicine
