Kaiser Permanente findings part of larger research effort on cannabis and pregnancy
By Jan Greene
Pregnant women who lived near recreational use cannabis retailers were more likely to use cannabis early in their pregnancies, new Kaiser Permanente research published March 4 in JAMA Network Open found.
However, the authors said they could not confirm the “direction” of the effect – whether women are more likely to use cannabis in pregnancy if they have easier access to it, or if cannabis retailers are more likely to open in neighborhoods that are receptive to cannabis. Future studies are needed to learn how changes in local recreational cannabis policies and retail availability of cannabis are associated with changes in prenatal cannabis use, the authors said.
Substantial evidence indicates exposure to cannabis in pregnancy is associated with having a low-birthweight baby, and there is some evidence of possible adverse effects on other fetal, neonatal and developmental outcomes.
“What’s important is that we provide universal health education about the potential risks of prenatal cannabis use and empower women to make informed decisions about cannabis use during pregnancy,” said lead author Kelly Young-Wolff, PhD, MPH, a research scientist with the Kaiser Permanente Northern California Division of Research. “Alternative forms of cannabis administration, including vaping, edibles, and dabbing are increasing in popularity following legalization of cannabis for recreational use, and studies are needed to understand whether the health risks differ depending on how cannabis is used.” Dabbing involves using a highly concentrated form of cannabis.
The research letter examined data on 35,195 women who were screened early in their pregnancies for cannabis use, both through self-report and by a urine toxicology test, at Kaiser Permanente Northern California in 2018. The researchers also collected addresses and license dates for 208 storefront recreational use cannabis retailers operating in 2018, after California legalized recreational cannabis use.
For each woman’s address they calculated proximity to, and density of, retailers operating during her pregnancy.
Eight percent of women in the sample screened positive for prenatal cannabis use during standard prenatal care (at approximately 8 weeks gestation). The analysis found that having more retailers within a 15-minute drive was associated with greater odds of prenatal cannabis use. Longer drive time was associated with lower odds of prenatal cannabis use. Women had an average drive time to the nearest retailer of 16 minutes and an average of 4 retailers within a 15-minute drive from their homes.
“Other research has shown that adults and adolescents who live closer to cannabis retailers are more likely to have favorable attitudes about cannabis,” Young-Wolff said. “And all of this is informed by robust literature in alcohol and tobacco that shows the closer you live to a tobacco retailer or alcohol retailer, the more likely you are to use these substances.”
Women need better access to information about health risks of cannabis use in pregnancy, Young-Wolff and two colleagues wrote in a previous editorial in JAMA Network Open. The editorial also highlighted the need for equitable access to supportive and non-punitive substance use treatment and recommended legal and regulatory policies to protect infants and children while not imposing criminal or discriminatory burdens on vulnerable communities.
Young-Wolff and Division of Research investigator Lyndsay Avalos, PhD, MPH, are pursuing several projects to better understand prenatal cannabis use. These studies are looking at the association between different modes of prenatal cannabis use and maternal, fetal, neonatal and developmental outcomes; whether prenatal substance use increased during the COVID-19 pandemic; and whether women who use cannabis, tobacco, or other substances before or during pregnancy are at increased risk of COVID-19.
“Women want reliable advice on the health effects of cannabis,” Avalos said. “We need more information about women’s use of cannabis and what impact it may have on their health and that of their babies.”
The cannabis retailer study was funded by the National Institute on Drug Abuse.
Additional coauthors were Sara R. Adams, MPH, Stacey E. Alexeeff, PhD, Stephen K. Van Den Eeden, PhD, of the Division of Research, and Alisa Padon, PhD, and Lynn D. Silver, MD, MPH, of the Public Health Institute in Oakland, Calif.
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About the Kaiser Permanente Division of Research
The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and society at large. It seeks to understand the determinants of illness and well-being, and to improve the quality and cost-effectiveness of health care. Currently, DOR’s 600-plus staff is working on more than 450 epidemiological and health services research projects. For more information, visit divisionofresearch.kaiserpermanente.org or follow us @KPDOR.