Living near recreational cannabis retailers tied to increased prenatal use

Key takeaways:

• Cannabis legalization in California was tied to an increase in cannabis use during early pregnancy.
• The increase was only observed in state jurisdictions that allowed adult-use cannabis retailers.

The implementation of recreational cannabis legalization in California in 2018 was associated with an immediate rise in rates of prenatal cannabis use in jurisdictions that permitted adult-use retailers, data show.

“The results underscore the importance of examining how variation in local policy shapes cannabis use behaviors,” Kelly Young-Wolff, PhD, MPH, a senior research scientist at Kaiser Permanente Northern California Division of Research, told Healio. “Importantly, increased rates were found regardless of whether prenatal cannabis use was defined by self-report or by toxicology testing, indicating that results were not merely due to an increased willingness to disclose prenatal cannabis use following legalization.”

Data suggest prenatal cannabis use may be rising due at least in part to the legalization of recreational cannabis, Young-Wolff and colleagues wrote in JAMA Health Forum. As of July, 38 states and Washington, D.C., have legalized medical cannabis; 24 states and Washington, D.C., have legalized recreational cannabis.

California legalized medical cannabis use in 1996 and passed recreational cannabis legalization in November 2016, with adult-use retail sales beginning in January 2018. However, local jurisdictions could ban or allow adult-use retail, and policies varied widely, according to the researchers.

Researchers analyzed data from 236,327 women in the Kaiser Permanente Northern California health system with 300,993 pregnancies, all universally screened for cannabis use during early pregnancy by self-report and toxicology testing from 2012 to 2019 (mean age, 30 years; 37.7% white; 26% Hispanic). Researchers examined the implementation of legal cannabis sales after California state recreational cannabis legalization (Nov. 9, 2016), as well as local policies allowing vs. banning medical retailers before legalization and adult-use retailers after legalization.

Any prenatal cannabis use was based on screening at entrance to prenatal care and was defined as a positive urine toxicology test result or self-report.

Before cannabis legalization, rates of prenatal cannabis use rose from 4.5% in January 2012 to 7.1% in January 2018, with no change in use rates when recreational cannabis legalization was passed in the state. Researchers did observe an increase in rates during the first month after recreational cannabis legalization implementation, rising to 8.6% in February 2018 for a level change RR of 1.1 (95% CI, 1.04-1.16). Results were similar when researchers defined prenatal cannabis use via toxicology test or by self-report.

In analyses stratified by jurisdictions that did or did not permit adult-use cannabis retailers, researchers found that the rise in prenatal cannabis use was only seen in the jurisdictions that allowed adult-use retailers (RR = 1.21; 95% CI, 1.1-1.33).

“Research suggests that pregnant people are bombarded with inaccurate messages from social media, cannabis retailers and peers suggesting that cannabis use during pregnancy is safe,” Young-Wolff told Healio. “Further, studies have shown that many pregnant patients turn to cannabis to try to self-medicate pregnancy-related symptoms, such as depression or morning sickness. It is important to remember that pregnant individuals care about having a safe pregnancy and are seeking information about the potential risks associated with prenatal cannabis use.”

Young-Wolff said the sharp rise in prenatal cannabis use after implementation of recreational cannabis legalization highlights the importance of enhancing public health awareness and education regarding the risks of cannabis use in pregnancy, particularly as legal landscapes evolve.

“It is crucial for health care providers, policymakers and community organizations to collaborate in ensuring pregnant individuals receive accurate information about these risks and adequate support,” Young-Wolff told Healio. “If pregnant individuals are considering using cannabis to self-medicate pregnancy-related symptoms, we encourage them to discuss those symptoms with their doctor and to use interventions recommended by clinical practice guidelines. By fostering an informed community, we can better protect the health of both mothers and their babies.”

The research builds on similar work from Young-Wolff and colleagues that assessed prenatal cannabis use in Northern California from 2012 to 2022. As Healio previously reported, those data demonstrated that prenatal cannabis use prevalence increased from 5.5% in 2012 to 9% in 2022, for an adjusted prevalence ratio (aPR) of 1.82 (95% CI, 1.72-1.92). Researchers observed similar prenatal cannabis prevalence via toxicology test (aPR = 1.7; 95% CI, 1.6-1.81) and self-report (aPR = 2.12; 95% CI, 1.95-2.3).

For more information:

Kelly C. Young-Wolf, PhD, MPH, can be reached at kelly.c.young-wolf@kp.org