Self-reported Medical and Nonmedical Cannabis Use Among Pregnant Women in the United States

Cannabis use increased among pregnant women in the United States from 2002 to 2014.¹ However, changes in cannabis use and frequency by trimester over time and national prevalence of medical cannabis use during pregnancy are unknown. Data from the National Survey on Drug Use and Health (NSDUH) were examined to address these knowledge gaps.

Data were from women aged 12 to 44 years who participated in the 2002-2017 NSDUH, a representative survey of the US civilian, noninstitutionalized population.² Collection of NSDUH data was approved by the institutional review board at RTI International.² Data were collected by interviewers during personal visits. Oral informed consent was received from respondents. The annual mean weighted response rate of the 2002-2017 NSDUH was 63.6%. Although methods to assess nonresponse bias vary, NSDUH trends have been comparable with trends from other population surveys.

The NSDUH collected sociodemographic characteristics, current pregnancy status, past-month cannabis use, past-month number of days of use, and daily/near daily use (≥20 days in the past month). Respondents who answered “yes” to “Are you currently pregnant?” were asked “How many months pregnant are you?”

Starting in 2013, respondents reporting past-year and past-month cannabis use were asked if any cannabis use was recommended by health care professionals. If answering “no,” respondents were classified as having past-month “nonmedical-only cannabis use.” If answering “yes,” they were asked if all cannabis use was recommended, and if answering “yes” to that question, they were classified as having past-month “medical-only cannabis use.”

Using logistic and linear regressions, we examined changes in adjusted (controlling for age, race/ethnicity, and family income) past-month cannabis use and use frequency and prevalence of past-month medical-only and nonmedical-only cannabis use by pregnancy status. Statistical significance was set at P < .05 by 2-sided t test. Analyses used SUDAAN software, release 11.0.1 (RTI International), to account for the NSDUH’s complex design and sampling weights.

Based on 467 100 respondents overall between 2002 and 2017, prevalence of past-month cannabis use, daily/near daily cannabis use, and number of days of cannabis use all increased among pregnant (and nonpregnant) women aged 12 to 44 years from 2002 to 2017 and was higher for the first trimester than for the second and third trimesters. Between 2002-2003 and 2016-2017, adjusted prevalence of past-month cannabis use (Figure, A) increased from 3.4% to 7.0% among pregnant women overall (difference, 3.6%; 95% CI, 1.92%-5.29%) and from 5.7% to 12.1% during the first trimester (difference, 6.4%; 95% CI, 2.56%-10.29%). Adjusted prevalence of past-month daily/near daily cannabis use (Figure, B) increased from 0.9% to 3.4% among pregnant women overall (difference, 2.5%; 95% CI, 1.40%-3.59%), from 1.8% to 5.3% during the first trimester (difference, 3.5%; 95% CI, 1.08%-5.98%), from 0.6% to 2.5% during the second trimester (difference, 1.9%; 95% CI, 0.42%-3.44%), and from 0.5% to 2.5% during the third trimester (difference, 2.0%; 95% CI, 0.25%-3.66%). Adjusted past-month mean number of days of cannabis use (Figure, C) increased from 0.4 to 1.1 days among pregnant women overall (difference, 0.7; 95% CI, 0.38-0.99), from 0.8 to 2.0 days during the first trimester (difference, 1.2; 95% CI, 0.46-1.92), from 0.2 to 0.7 days during the second trimester (difference, 0.5; 95% CI, 0.08-0.81), and from 0.3 to 0.7 days during the third trimester (difference, 0.4; 95% CI, −0.06 to 0.92).

Among pregnant women between 2013 and 2017, past-month cannabis use was 0.5% for medical-only purposes (Table). Medical-only cannabis use did not differ by pregnancy status, but nonmedical-only cannabis use was higher among nonpregnant women (8.7%) than pregnant women (4.0%) (difference, 4.7%; 95% CI, 4.01%-5.38%).

Prevalence and frequency of past-month cannabis use among pregnant women increased between 2002 and 2017 and were higher for the first trimester than later trimesters. Past-month clinician-recommended cannabis use was low among pregnant women, and nonmedical use was lower than among nonpregnant women. Although many states have approved cannabis for nausea/vomiting (including in pregnancy),³ the results suggest that clinicians might not recommend it during pregnancy, perhaps reflecting the American College of Obstetricians and Gynecologists recommendation that pregnant women discontinue cannabis consumption.⁴ Study limitations include likely underestimated cannabis use during pregnancy (eg, while unaware of being pregnant).⁵ Also, the NSDUH is subject to recall bias.

Cannabis effects on fetal growth (eg, low birth weight and length) may be more pronounced in women who consume marijuana frequently, especially in the first and second trimesters.⁴ This study highlights the importance of screening and interventions for cannabis use among all pregnant women.

Accepted for Publication: May 22, 2019.

Corresponding Author: Beth Han, MD, PhD, MPH, Substance Abuse and Mental Health Services Administration, 5600 Fishers Ln, 15E17B, Rockville, MD 20857 (beth.han@samhsa.hhs.gov).

Published Online: June 18, 2019. doi:10.1001/jama.2019.7982

Author Contributions: Dr Han had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Han, Compton, McCance-Katz.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Volkow, Han.

Critical revision of the manuscript for important intellectual content: Han, Compton, McCance-Katz.

Statistical analysis: Han.

Administrative, technical, or material support: Han, McCance-Katz.

Supervision: Volkow.

Conflict of Interest Disclosures: Dr Compton reported ownership of stock in General Electric Co, 3M Co, and Pfizer Inc. No other disclosures were reported.

Funding/Support: This study was jointly sponsored by the National Institute on Drug Abuse of the National Institutes of Health and the Substance Abuse and Mental Health Services Administration of the US Department of Health and Human Services.

Role of the Funder/Sponsors: The sponsors supported the authors who were responsible for preparation, review, and approval of the manuscript and the decision to submit the manuscript for publication. The sponsors had no role in the design and conduct of the study; analysis and interpretation of the data; or decision to submit the manuscript for publication. The sponsors reviewed and approved the manuscript.

Disclaimer: The findings and conclusions of this study are those of the authors and do not necessarily reflect the views of the National Institute on Drug Abuse of the National Institutes of Health, the Substance Abuse and Mental Health Services Administration, or the US Department of Health and Human Services.