Trends in perception of risk of regular marijuana use among US pregnant and nonpregnant reproductive-aged women

OBJECTIVE

Marijuana use may pose risks for reproductive and perinatal health.^1,2 Marijuana use among pregnant and reproductive-aged women increased 62% in the last decade.³ Our objective was to investigate time trends in the perception of the risk of regular marijuana use among US pregnant and nonpregnant reproductive-age women.

STUDY DESIGN

We analyzed National Survey on Drug Use and Health data from 2005 through 2015, a nationally representative survey on substance use in the civilian, noninstitutionalized US population.⁴ Data were collected using computer-assisted self-interviewing techniques to maximize privacy and confidentiality. We included female respondents aged 18–44 years who were pregnant (unweighted N = 8713) or not pregnant (unweighted N = 161,902).

Respondents were asked: “How much do people risk harming themselves physically and in other ways when they smoke marijuana once or twice a week?” Possible responses included no risk, slight risk, moderate risk, great risk, or don’t know. We calculated time trends in respondents answering no risk. We used logistic regression to examine annual changes in the perception of no risk of regular marijuana use, adjusted for age, race/ethnicity, education, pregnancy status, and marijuana use within the prior 30 days. Average predicted probabilities of perceiving no risk of regular marijuana use were derived from regression models to show adjusted changes in risk perception over time among pregnant and nonpregnant women by marijuana use status. Analyses were weighted to account for the complex survey design. The National Survey on Drug Use and Health is deidentified, publicly available data, and this study did not require institutional review board approval.

RESULTS

The average predicted probability of reporting no risk of regular marijuana use among all women increased from 4.6% in 2005 (95% confidence interval [CI], 4.2–5.0) to 19.0% in 2015 (95% CI, 18.3–19.7). Among women who did not report marijuana use in the prior 30 days, the average predicted probability of reporting no risk of regular marijuana use increased from 3.5% (95% CI, 3.0–3.9) to 16.5% (95% CI, 14.9–18.1) among pregnant women and from 3.1% (95% CI, 2.8–3.4) to 14.8% (95% CI, 14.0–15.5) among nonpregnant women (Figure). Among womenwho reported marijuana use in the prior 30 days, the average predicted probability of reporting no risk of regular marijuana use increased from 25.8% (95% CI, 23.0–28.7) to 65.4% (95% CI, 62.5–68.4) among pregnant women and from 23.7% (95% CI, 21.8–25.6) to 62.6% (95% CI, 61.0–64.3) among nonpregnant women. The probability of women reporting no risk of daily cigarette smoking also increased over time (1.1% in 2005 vs 3.4% in 2015; data not shown), although this increase was far smaller than that observed for marijuana use.

FIGURE. Average predicted probability of reporting no risk of regular marijuana use.

The data are from the National Survey of Drug Use and Health pooled cross-sectional data from 2005 through 2015. Figure shows average predicted probabilities in each year of reporting that using marijuana once or twice a week has no risk. Estimates are from weighted logistic regression models adjusting for age (18–25, 26–34, and 35–44 years), race and ethnicity (on-Hispanic white, non-Hispanic black, non-Hispanic other race, and Hispanic ethnicity), educational attainment (less than high school, high school graduate, or more than high school education), pregnancy status, and self-reported marijuana use in the prior 30 days. Error bars indicate 95% confidence intervals.

CONCLUSION

Perception that regular marijuana use has no risk has increased 3-fold from 2005 through 2015 among US reproductive-aged women. Pregnant and nonpregnant women who used marijuana in the prior 30 days more commonly perceived that regular use had no risk, relative to women who had no such marijuana use. However, perception that regular marijuana use has no risk increased, even among women without marijuana use in the prior 30 days. We relied on self-reported marijuana use, which might underestimate the true prevalence. Women were asked about perception of risk of marijuana use generally and not specifically about perinatal marijuana use.

Because 30 states have laws permitting medical or recreational marijuana, it is important to understand patterns in women’s perceptions of the risks of regular marijuana use. Findings support the importance of investigating the effects of marijuana use on reproductive health.