Last summer, another JAMA study reported that the rate of cannabis use among pregnant women nearly doubled between 2002 and 2017. Other studies have suggested that these expecting mothers are using cannabis to relieve stress, nausea, or pain, but a team of researchers from one of California's largest healthcare companies set out to investigate whether mental health also played a role in prenatal cannabis use.
Kelly C. Young-Wolff, PhD, MPH, a research scientist from the Kaiser Permanente Northern California (KPNC) Division of Research, launched a new study to determine if pregnant women suffering from trauma or mental health issues were more likely to use pot. To investigate the issue, Young-Wolff and her fellow researchers turned to KNPC's integrated healthcare system, which has collected data on hundreds of thousands of pregnancies.
Pregnant women who receive prenatal care at KPNC facilities are asked to self-report any mental health or substance use issues on a questionnaire. Doctors also conduct a urine drug test during prenatal screenings, and women who test positive undergo a second test for confirmation. Although some women did not complete the questionnaire or drug test, researchers were still able to acquire data on 196,022 pregnant women who visited these facilities between 2012 and 2017.
Out of these nearly 200,000 women, only 6 percent (11,681) were using cannabis while pregnant. Researchers then used electronic health records and the self-report questionnaires to determine if any of these women were suffering from depressive, anxiety, or trauma disorders during their pregnancy. Among all the subjects, the incidence of these issues ranged from 1.9 percent (domestic violence) to 11 percent (depression symptoms of at least moderate severity).
The study reports that women suffering from mental health issues were in fact more likely to use cannabis while pregnant. Researchers calculated that prenatal cannabis users were more likely to have an anxiety disorder (8.3 percent of cannabis users vs. 4.7 percent of non-users), a depressive disorder (10.6 percent vs. 4.3 percent), or both at once (8.4 percent vs. 3.1 percent). Prenatal cannabis users were also more likely to have been diagnosed with trauma (8.3 percent vs. 2.0 percent) or to have self-reported intimate partner violence (4.4 percent vs. 1.8 percent).
“These results support previous qualitative findings that pregnant women self-report using cannabis to manage mood and stress and suggest a dose-response association, with higher odds of cannabis use associated with co-occurring depressive and anxiety disorders and greater depression severity,” the authors concluded.
The study does have a number of limitations, though. All of the subjects were sourced from one health care system in Northern California, and as the researchers note, “the findings may not generalize to all pregnant women.” The evaluations were only taken around the 8th week of pregnancy, and do not account for cannabis use occurring before or after that date. Also, the study relies on self-reports of mental health, which may not always be entirely honest.
The study asserts that “no amount of cannabis use during pregnancy has been shown to be safe,” but the hard truth of the matter is that the scientific community is not entirely certain about what risks cannabis might pose to the developing child. Another JAMA study from last year suggested that cannabis use is linked to premature birth or other poor birth outcomes, and another recent study found that weed could increase the risk of miscarriage.
Other studies have come to the opposite conclusion, however. A Jamaican study found that children who had been exposed to cannabis actually showed better physiological stability at the age of one month than children who had not been exposed to weed.
Still, health authorities are erring on the side of caution and advising all expecting mothers to steer clear of pot. The US Food and Drug Administration issued a memo last fall urging all mothers to stay away from all CBD and THC products, even when breastfeeding. California has also officially declared cannabis a pregnancy risk, and Michigan is about to require all legal weed products to contain warnings against prenatal consumption.