Abstract
Background and Objectives
Despite marijuana's association with adverse pregnancy and birth outcomes, its use during pregnancy increased over the last two decades. During this period, medical marijuana has been legalized in 38 states and the District of Columbia. States with legalized medical marijuana have observed increased marketing of marijuana and related products. This study aims to examine the association between state‐level medical marijuana legalization and marijuana use during pregnancy in the United States.
Methods
Using the 2015–2021 National Survey on Drug Use and Health, we evaluated the association between marijuana use in the past month among currently pregnant mothers (N = 4338) and legalized medical marijuana in their state of residence. Survey‐weighted descriptive, bivariate, and multivariable logistic regression analyzes were performed.
Results
About 5.7% of pregnant women reported using marijuana in the past month, and 59.0% lived in a state where medical marijuana was legalized across 2015–2021. Compared to those living in states without marijuana legalization, more pregnant women living in states with marijuana legalization reported using marijuana (4.6% vs. 6.5%). In the multivariable model, pregnant women residing in states with medical marijuana legalization were more likely to use marijuana than residents of states without legalization (adjusted Odds Ratio: 1.56; 95% Confidence Interval: 1.11–2.18).
Conclusion and Scientific Significance
This is the first known study to find that pregnant women living in states where medical marijuana is legalized are more likely to use marijuana during pregnancy. Pregnant women should be informed of adverse pregnancy and birth outcomes linked to marijuana use during pregnancy.
INTRODUCTION
Marijuana is the most commonly used drug during pregnancy in the United States. 1 In 2021, approximately 7.2% of pregnant women have used marijuana, 2 an increase from 3.4% reported in 2002. 3 This significant increase in marijuana use among pregnant women over the years raises concerns about its potential impact on maternal health and fetal development. A recent study has found relatively widespread marijuana use during pregnancy, with a notable portion of women continuing their marijuana usage during this period. 4 Some expectant mothers perceive marijuana as a potential remedy for their pregnancy‐related symptoms such as nausea and vomiting, although studies have found that women who used marijuana before becoming pregnant are more likely to experience nausea during their pregnancy. 4 , 5 It is important for healthcare and public health professionals and policymakers to address this issue to ensure the well‐being of the mother and the child.
Prenatal exposure to marijuana has been associated with adverse birth outcomes, including low birth weight, fetal growth restriction, premature birth, stillbirth, and neurodevelopmental effects that can extend into young adulthood. Chronic marijuana use may also increase the risk of developing cannabinoid hyperemesis. 6 Additionally, studies have shown that women who use marijuana during pregnancy are more likely to engage in the use of other substances, such as alcohol, tobacco, opioid, and other illicit drugs. 7 , 8 , 9 This concurrent use can lead to additive or synergistic effects that exacerbate adverse outcomes for both the mother and infant. 10 Because of these potential risks, it is recommended that marijuana should not be used during pregnancy due to insufficient safety data and concerns regarding fetal development, 11 and pregnant mothers should consult with healthcare professionals for safe and effective alternatives to manage pregnancy‐related symptoms.
In 2021, 36.4 million people in the United States older than the age of 12 reported using marijuana in the past month. 12 As of April 2023, Medical marijuana is legal in 38 states and the District of Columbia and recreational marijuana is legal in 23 states (plus Guam, the Northern Mariana Islands, the US Virgin Islands, and the District of Columbia). 13 The legalization of medical or recreational marijuana in US states generally corresponds to higher rates of use compared to states where all forms of marijuana are illegal. 14 , 15 In a study conducted in Colorado, a state where medical marijuana is legalized, almost 70% of marijuana dispensaries recommended products to pregnant women to treat nausea without obstetrician consultation. 16 However, it is not clear whether this increase is directly caused by legalization or is influenced by other factors. What is most concerning is that states that have legalized medical marijuana have experienced a significant increase in marketing campaigns promoting marijuana use and increased availability of novel marijuana products containing tetrahydrocannabinol at concentrations that have not been thoroughly evaluated for safety in humans. 17 Moreover, pregnant women's risk perception of medical marijuana use is much lower than recreational marijuana. 18 It is therefore important to investigate the impact of medical marijuana legalization status on marijuana use during pregnancy.
Despite being aware of the potential harm of marijuana use during pregnancy, a greater proportion of pregnant women still support some level of marijuana legalization, which suggests a complex and nuanced attitude towards marijuana use during pregnancy. 4 With varying laws and regulations on marijuana across different regions, it is crucial to communicate accurate information to the public, especially to pregnant women and those considering pregnancy. There is limited evidence on the impact of state‐level medical marijuana legalization on marijuana use during pregnancy. We hypothesize that the prevalence of marijuana use during pregnancy would be higher among women who resided in a state where medical marijuana was legal.
METHODS AND MATERIALS
Data
The study used the National Survey on Drug Use and Health (NSDUH) data from 2015 to 2021. NSDUH is a nationally representative cross‐sectional survey on the use of alcohol, tobacco, and other substance use and misuse, substance use disorder, and behavioral health treatments, collected from noninstitutionalized U.S. population each year by the Substance Abuse and Mental Health Services Administration. 19 NSDUH adopts a multistage clustered probability sampling of all 50 states and the District of Columbia. Each state is stratified into approximately equal‐sized regions according to a composite size measure (i.e., population weighted by state and age group sampling rates) called state sampling regions (SSRs). This yields 750 SSRs across the US. In the first stage of sampling, census tracts within each SSR are selected, followed by census block groups within census tracts, and then area segments (collections of census blocks) within census block groups. In the final stage, dwelling units (DUs) are selected within each segment, and within each selected DU, up to two residents ≥12 years are selected for the interview. Using census block groups as opposed to smaller segments reduces the clustering effect. 20 We pooled NSDUH data collected over 7 years to improve the precision of estimates and to avoid the suppression of estimates due to small sample size. 21 We used person‐level weights (divided by 7 to account for 7 years' data) that are calibrated to the population control totals obtained from the U.S. Census Bureau. However, given the cross‐sectional nature of NSDUH which includes different persons in each year, longitudinal analysis could not be performed. NSDUH data set also includes imputed variables with missing values using two imputation procedures, e.g., predictive mean neighborhood, and modified predictive mean neighborhood.
The study sample included 4338 women who were pregnant at the time of the survey and had complete information on marijuana use during the past 30 days and their residence in a state where medical marijuana was legal or not. All analyzes were estimated using the survey weight to account for the complex survey design of NSDUH and the nationally representative weighted pool which includes 2,006,334 pregnant women. 22
Measures
Dependent variable
The main outcome variable for this study was marijuana use during the past 30 days. Respondents were asked “how long it has been since they used marijuana?” with response categories: (1) within the past 30 days, (2) more than 30 days ago but within the past 12 months, (3) more than 12 months ago, (8) used at some point in the past 12 months, and (9) used at some point in the lifetime. From this response, NSDUH data imputed a variable “irmjrc‐marijuana recency” with categories, (1) within the past 30 days, (2) more than 30 days ago but within the past 12 months, (3) more than 12 months ago. For this study, we recoded this irmjrc variable to a dichotomous variable with (1) marijuana used in the last 30 days and (2) did not use marijuana in the last 30 days. Since the pregnancy test comes positive almost 1 month after conception, we consider that marijuana use reported in the last 30 days among those who knew their positive pregnancy status adequately captures marijuana use during pregnancy.
Independent variable
In the publicly available NSDUH data MEDMJST2 variable indicates the status of the medical marijuana law in the state of residence of the respondent. This variable has two options: (1) medical marijuana law was approved at the time of the survey; (0) medical marijuana law was not approved at the time of the survey.
Covariates
Based on previous literature, sociodemographic and other characteristics were included as covariates: trimester of the pregnancy (third, second, first), age (18–25, 26–34, 35–49 years), education (less than high school, high school, some college/associate degree, college graduate or higher), race/ethnicity (Non‐Hispanic other, Non‐Hispanic White, Non‐Hispanic African American, Hispanic), marital status (married, never been married, widowed/separated/divorced), employment status (full‐time, part‐time, unemployed, other), annual household income (<$20,000, $20,000‐$49,999, $50,000‐$74,999, ≥$75,000), place of residence (large metro, small metro, onmetro), health insurance status (insured, uninsured), risk perception on weekly marijuana use (have risk, no risk), daily cigarette use in the past month (no, yes), unmet mental health needs in the past year (no, yes), religiosity (low/medium, high), and major depressive episode (MDE) in past year (no, yes).
Risk perception on weekly marijuana use was created by recoding the variable on risk perception of using marijuana once or twice a week (coded 1 = No risk, 2 = slight risk, 3 = moderate risk, 4 = great risk). We recoded the variable to a dichotomous variable with no risk = 0, and slight, moderate, and great risk = 1, have risk. ‘Unmet mental health needs in the past year’ variable was derived from the question “During the past 12 months, was there any time when you needed mental health treatment or counseling for yourself but didn't get it?” with dichotomous responses (yes/no). Religiosity was derived by summing up responses to two 4‐point Likert scale questions on (i) “My religious beliefs are very important”; (ii) “My religious beliefs influence my decisions” (coded 1 = strongly disagree, 2 = disagree, 3 = agree, 4 = strongly agree) and then divided into low/medium (2–6) and high (7–8). Exploratory factor analysis shows that the scale describes religiosity well (Eigenvalue = 1.49) and has internal reliability (Cronbach's alpha = 0.90). MDE was defined as experience of a depressed mood or loss of interest or pleasure in daily activities and other additional symptoms based on the DSM‐IV criteria over a period of at least 2 weeks in the past year based on the survey responses. 23 , 24
Statistical analysis
Descriptive statistics, for example, frequencies and proportions, were used to describe sample characteristics. Using Rao‐Scott Chi‐square test, differences in proportions of women using marijuana during pregnancy by their residence in a state where medical marijuana was legal and each covariate were examined. Multivariable logistic regression analysis was performed to assess the association between residence in a state where medical marijuana was legal and marijuana use during pregnancy. Both crude and adjusted odds ratio and corresponding 95% confidence interval (CI) were reported. p < .05 was considered as statistically significant. We also conducted a zero‐inflated negative binomial regression model to find out the relationship between residence in a state with legalized medical marijuana and the number of days of marijuana use during pregnancy and reported the results in the supplementary tables. All analyzes were weighted using pooled weight using Stata 18.0.
RESULTS
The study findings reveal that 5.7% of U.S. pregnant women used marijuana during the month preceding the survey across the pooled data set from 2015 to 2021. Two‐thirds (67.0%) of the pregnant women who used marijuana during the past month resided in a state where medical marijuana was legal at the time of the survey. Most of the pregnant women who used marijuana in the past month were in their first trimester of pregnancy, 18–25 years old, had some college/associate degree, non‐Hispanic other, had never been married, lived in a large metro area, and perceived no risk associated with weekly marijuana use (Table 1).
Table 1.
Characteristics of pregnant women who used marijuana during the past month, National Survey on Drug Use and Health (NSDUH) 2015–2021, (N = 4338).
| Women who used marijuana during the last 30 days | Women who did not use marijuana during the last 30 days | |||
|---|---|---|---|---|
| Characteristics | Total (N = 4338) Weighted % | N = 291 (5.7%) Weighted % |
N = 4047 (94.3%) Weighted % |
p value† |
| Medical marijuana legal state residence | .031 | |||
| No | 41.0 | 33.0 | 41.5 | |
| Yes | 59.0 | 67.0 | 58.5 | |
| Trimester | .008 | |||
| Third | 33.8 | 23.5 | 34.4 | |
| Second | 37.1 | 28.4 | 37.7 | |
| First | 29.1 | 48.1 | 27.9 | |
| Age | .014 | |||
| 26–34 | 53.4 | 40.8 | 54.1 | |
| 18–25 | 29.5 | 47.9 | 28.4 | |
| 35–49 | 17.1 | 11.4 | 17.4 | |
| Education | <.001 | |||
| College graduate or higher | 36.2 | 11.9 | 37.7 | |
| Less than high school | 11.6 | 14.8 | 11.4 | |
| High school | 22.1 | 31.6 | 21.5 | |
| Some college/associate degree | 30.1 | 41.7 | 29.4 | |
| Race/ethnicity | .011 | |||
| Non‐Hispanic White | 55.5 | 51.9 | 55.8 | |
| Non‐Hispanic African American | 15.5 | 28.9 | 14.7 | |
| Non‐Hispanic other | 9.6 | 6.4 | 9.8 | |
| Hispanic | 19.3 | 12.9 | 19.7 | |
| Marital status | <.001 | |||
| Married | 60.3 | 28.9 | 62.3 | |
| Never been married | 33.9 | 64.2 | 32.0 | |
| Widowed/separated/divorced | 5.8 | 6.9 | 5.7 | |
| Employment status | .073 | |||
| Full‐time | 45.3 | 43.4 | 45.5 | |
| Part‐time | 16.7 | 10.4 | 17.1 | |
| Unemployed | 38.0 | 46.2 | 374 | |
| Other | ||||
| Annual household income | .002 | |||
| ≥$75,000 | 36.3 | 21.6 | 35.5 | |
| <$20,000 | 18.1 | 30.9 | 18.8 | |
| $20,000–$49,999 | 29.5 | 35.3 | 29.8 | |
| $50,000–$74,999 | 16.1 | 12.2 | 15.9 | |
| Place of residence | .185 | |||
| Large metro | 55.5 | 52.4 | 55.7 | |
| Small metro | 30.5 | 29.0 | 30.6 | |
| Nonmetro | 14.0 | 18.6 | 13.7 | |
| Health insurance | .076 | |||
| Uninsured | 6.4 | 9.9 | 6.2 | |
| Insured | 93.6 | 90.1 | 93.8 | |
| Risk perception on weekly marijuana use | <.001 | |||
| Have risk | 76.9 | 29.1 | 79.8 | |
| No risk | 23.1 | 70.9 | 20.2 | |
| Daily cigarette use in past month | <.001 | |||
| No | 92.9 | 72.0 | 94.1 | |
| Yes | 7.1 | 28.0 | 5.9 | |
| Religiosity | .001 | |||
| High | 36.4 | 19.3 | 37.4 | |
| Low/medium | 63.6 | 80.7 | 62.6 | |
| Unmet mental health needs | <.001 | |||
| No | 92.4 | 79.8 | 93.1 | |
| Yes | 7.6 | 20.2 | 6.9 | |
| Major depressive episode (MDE) | <.001 | |||
| No | 92.3 | 79.2 | 93.2 | |
| Yes | 7.7 | 20.8 | 6.8 | |
| Year | .223 | |||
| 2015 | 14.9 | 7.9 | 15.3 | |
| 2021 | 13.1 | 16.8 | 12.8 | |
| 2020 | 12.6 | 16.6 | 12.4 | |
| 2019 | 13.3 | 12.4 | 13.3 | |
| 2018 | 16.1 | 13.0 | 16.3 | |
| 2017 | 15.0 | 19.7 | 14.7 | |
| 2016 | 15.0 | 13.6 | 15.1 | |
Bold p values are statistically significant at cut‐off value < .05.
In the bivariate analysis, residence in a state where medical marijuana was legal, trimester, age, education, race/ethnicity, marital status, annual household income, risk perception on weekly marijuana use, daily cigarette use in the past month, religiosity, unmet mental health needs in the past year, and MDE in the past year were significantly associated with marijuana use during pregnancy (Table 1).
In the multivariable analysis, higher odds of marijuana use during pregnancy were observed among women who resided in a state where medical marijuana was legal [adjusted odds ratio (aOR): 1.56, 95% CI: 1.11–2.18)] compared with those who resided in a state where medical marijuana was not legal; were in their first trimester of pregnancy (aOR: 2.66, 95% CI: 1.86–3.78) compared with those who were in third trimester; were non‐Hispanic African American (aOR: 2.04, 95% CI: 1.16–3.61) compared with non‐Hispanic White; who perceived no risk associated with weekly marijuana use (aOR: 6.17, 95% CI: 3.65–10.43) compared with those who perceived weekly marijuana use had risk; used cigarette daily in the past month (aOR: 3.86, 95% CI: 2.01–7.42) compared with those who did not; had low/medium level of religiosity (aOR: 1.86, 95% CI: 1.14–3.05) compared with those who had high religiosity; had unmet mental health needs in the past year (aOR: 1.64, 95% CI: 1.04–2.60) compared with those who did not; and had MDE in the past year (aOR: 2.14; 95% CI: 1.31–3.50) compared with those who did not; those who were pregnant in 2017 (aOR: 2.20, 95% CI: 1.20–4.03), 2020 (aOR: 3.10, 95% CI: 1.11–8.65), and 2021 (aOR: 2.58, 95% CI: 1.02–6.54) than those who were pregnant in 2015 (Table 2). The model had a good fit (p = .1091) according to the Archer‐Lemeshow test statistic.
Table 2.
Correlates of marijuana use during pregnancy, National Survey on Drug Use and Health (NSDUH) 2015–2021, (N = 4338).
| Characteristics | Crude | Adjusted | ||
|---|---|---|---|---|
| Odds ratio | 95% CI | Odds ratio | 95% CI | |
| Medical marijuana legal state residence | ||||
| No | 1.00 | ‐ | 1.00 | ‐ |
| Yes | 1.43*** | 1.03–2.00 | 1.56*** | 1.11–2.18 |
| Trimester | ||||
| Third | 1.00 | ‐ | 1.00 | ‐ |
| Second | 1.10 | 0.58–2.08 | 1.16 | 0.59–2.25 |
| First | 2.52* | 1.77–3.57 | 2.66* | 1.86–3.78 |
| Age | ||||
| 26–34 | 1.00 | ‐ | 1.00 | ‐ |
| 18–25 | 2.23* | 1.51–3.31 | 1.60 | 0.95–2.70 |
| 35‐49 | 0.86 | 0.32–2.37 | 1.67 | 0.52–5.33 |
| Education | ||||
| College graduate or higher | 1.00 | ‐ | 1.00 | ‐ |
| Less than high school | 4.12* | 2.03–8.39 | 1.64 | 0.56–4.76 |
| High school | 4.68* | 2.44–8.97 | 1.77 | 0.58–5.37 |
| Some college/associate degree | 4.51* | 2.43–8.34 | 2.40 | 0.75–7.73 |
| Race/ethnicity | ||||
| Non‐Hispanic White | 1.00 | ‐ | 1.00 | ‐ |
| Non‐Hispanic African American | 2.11** | 1.29–3.46 | 2.04** | 1.16–3.61 |
| Non‐Hispanic other | 0.70 | 0.32–1.53 | 0.87 | 0.38–1.99 |
| Hispanic | 0.69 | 0.29–1.64 | 0.95 | 0.34–2.68 |
| Marital status | ||||
| Married | 1.00 | ‐ | 1.00 | ‐ |
| Never been married | 4.33* | 2.51–7.44 | 1.63 | 0.82–3.24 |
| Widowed/separated/divorced | 2.60** | 1.36–4.95 | 1.07 | 0.41–2.75 |
| Employment status | ||||
| Full‐time | 1.00 | ‐ | 1.00 | ‐ |
| Part‐time | 0.64 | 0.35–1.15 | 0.46 | 0.21–1.03 |
| Unemployed/Other | 1.29 | 0.82–2.04 | 0.76 | 0.46–1.26 |
| Annual household income | ||||
| ≥$75,000 | 1.00 | ‐ | 1.00 | ‐ |
| <$20,000 | 2.87** | 1.50–5.49 | 0.87 | 0.44–1.72 |
| $20,000–$49,999 | 2.01*** | 1.14–3.57 | 0.91 | 0.43–1.94 |
| $50,000–$74,999 | 1.28 | 0.73–2.24 | 0.83 | 0.45–1.54 |
| Residence | ||||
| Large metro | 1.00 | ‐ | 1.00 | ‐ |
| Small metro | 1.01 | 0.72–1.40 | 0.86 | 0.57–1.30 |
| Nonmetro | 1.44 | 0.91–2.30 | 0.96 | 0.60–1.56 |
| Health insurance | ||||
| Uninsured | 1.00 | ‐ | 1.00 | ‐ |
| Insured | 1.66 | 0.94–2.94 | 1.35 | 0.71–2.58 |
| Risk perception on weekly marijuana use | ||||
| Have risk | 1.00 | ‐ | 1.00 | ‐ |
| No risk | 9.58* | 5.16–17.78 | 6.17* | 3.65–10.43 |
| Daily cigarette use in past month | ||||
| No | 1.00 | ‐ | 1.00 | ‐ |
| Yes | 6.23* | 4.04–9.61 | 3.86* | 2.01–7.42 |
| Religiosity | ||||
| High | 1.00 | ‐ | 1.00 | ‐ |
| Low/medium | 2.50** | 1.45–4.32 | 1.86*** | 1.14–3.05 |
| Unmet health needs | ||||
| No | 1.00 | ‐ | 1.00 | ‐ |
| Yes | 3.43* | 2.29–5.12 | 1.64*** | 1.04–2.60 |
| Major depressive episode (MDE) | ||||
| No | 1.00 | ‐ | 1.00 | ‐ |
| Yes | 3.53* | 2.35–5.30 | 2.14** | 1.31–3.50 |
| Year | ||||
| 2015 | 1.00 | ‐ | 1.00 | ‐ |
| 2021 | 2.54*** | 1.12–5.75 | 2.58*** | 1.02–6.54 |
| 2020 | 2.59*** | 1.12–6.01 | 3.10*** | 1.11–8.65 |
| 2019 | 1.79 | 0.93–3.46 | 1.72 | 0.78–3.79 |
| 2018 | 1.54 | 2.75 | 1.53 | 0.77–3.06 |
| 2017 | 2.59* | 1.56–4.30 | 2.20*** | 1.20–4.03 |
| 2016 | 1.74 | 0.88–3.42 | 1.93 | 0.87–4.31 |
p < .001 (cut‐off value for significance is <.05)
p < .01
p < .05.
We also found in the zero‐inflated negative binomial regression model with number of days of marijuana use during the past month as outcome variable that pregnant women residing in a state with medical marijuana legalization increased the number of days of marijuana use by a factor of exp(0.838) = 2.31 than women in a state without medical marijuana legalization (Table S2).
DISCUSSION
The study results show that 5 57.% of pregnant women used marijuana in the previous month, and more than two‐thirds of them lived in a state where medical marijuana was legal. Among the pregnant women who used marijuana in the last 30‐days, 70.9% did not perceive any risk associated with weekly marijuana use. This is alarming given that marijuana is a risk factor for low birth weight, 25 preterm labor, admission to the neonatal intensive care unit, 26 and still births. 27
Our results also show that marijuana use during pregnancy is 56% higher among pregnant women in states where medical marijuana is legal compared with states where medical marijuana is not legal. This indicates that increased availability of marijuana through marijuana legalization is likely increasing access to marijuana and marijuana use among pregnant women. 25 It is also reported that the rate of marijuana treatment admissions was higher among pregnant women living in states where medical marijuana was legal compared with states where medical marijuana is not legal. 28
Additionally, our findings show that those who were in their first trimester of pregnancy, perceived no risk associated with weekly marijuana use, and who used cigarette daily in the past month experienced higher odds of marijuana use during pregnancy. These findings are consistent with previous literature that shows early trimester of pregnancy, co‐use of tobacco, and perceiving no‐risk of weekly marijuana use being associated with increased odds of marijuana use among pregnant women. 29 This result shows the pregnant women lack the vital information on the harmful effects of marijuana use during pregnancy and the importance of imparting the information during first trimester of pregnancy, when the marijuana use is observed more among pregnant women.
Moreover, those who were non‐Hispanic African American, had unmet mental health needs in the past year, and had MDE in the past year were more likely to use marijuana during pregnancy. It is possible that individuals who do not have insurance coverage or do not receive appropriate medical care use marijuana in place of other treatment options. Previous research shows that pregnant, non‐Hispanic African Americans are less likely to receive prescription pain medications, 30 and less likely to receive mental health treatment 31 compared with their non‐Hispanic White counterparts. It is also reported that non‐Hispanic African Americans women are less likely to have perinatal insurance coverage 32 or receive reproductive health services 33 compared with their non‐Hispanic White counterparts. This result demonstrates racial disparities in marijuana use and suggest that targeted approaches are required to make non‐Hispanic African American women aware of the harmful effect of marijuana use during pregnancy. We also found that the likelihood of marijuana use during pregnancy was higher during COVID‐19 pandemic (2020 and 2021) than in 2015. This result is supported by the other study findings, 34 but should be viewed with caution as NSDUH data collection methods underwent major changes during the COVID‐19 pandemic (from solely in‐person to web‐based in 2020, and both in‐person and web‐based since 2021).
Our study has several limitations. Due to the cross‐sectional nature of the data, we cannot assess any causal relationship in the analysis. Also, the cross‐sectional data does not allow us to assess the changes in marijuana use among pregnant women during prenatal period. NSDUH only collects data from the noninstitutionalized U.S. population, which may exclude information from the prisoners or population experiencing homelessness. Thus, reported substance use and risks may be underestimated. Recall or self‐report bias may also lead to inaccurate responses to the questions, especially on marijuana use. Pregnancy status and trimester are also self‐reported, which might be validated from medical records in future studies. Finally, we could not assess nor control for the role of recreational marijuana legalization on marijuana use during pregnancy due to the unavailability of recreational marijuana legalization information in the public‐use files of NSDUH. Future studies with state identifiers and differential rollout of medical and recreational marijuana legalization in different states can use the difference‐in‐differences method for a more robust analysis of the potential impact of greater availability and accessibility of marijuana on use during pregnancy.
Despite these limitations, our study also has several strengths. First, this study used a nationally representative data set to examine the association between medical marijuana legalization and marijuana use among pregnant women in the US. Second, we pooled 7 years of data to increase the precision of the estimates. Third, we included several pertinent socio‐demographic and pregnancy‐related characteristics to account for possible confounding factors in the analysis. Finally, this is the first study we are aware of to examine the association between medical marijuana legalization and marijuana use during pregnancy utilizing a national data set.
An increasing number of states are passing or considering the passage of medical marijuana laws. However, the benefits or the harms associated with medical marijuana laws are not evident. Thus, it is important for clinicians and the public to learn about the adverse effects of marijuana use during pregnancy. Such information will help inform future policy decisions with regard to marijuana use during pregnancy.
CONCLUSIONS
Pregnancy is a teachable and motivating time for women to engage in healthy behavior modification. 35 Prenatal marijuana use is a modifiable risk factor. Clinicians should be equipped with the necessary training, tools, and resources to offer appropriate screening, patient education, and care for women who use marijuana during pregnancy. In a constantly changing legal landscape surrounding marijuana, it becomes imperative to provide clear and unambiguous messaging regarding the adverse effects of marijuana use during pregnancy.
CONFLICT OF INTEREST STATEMENT
The authors declare no conflicts of interest.
Supporting information
Supporting information.
Supporting information.
ACKNOWLEDGMENTS
Mohammad Rifat Haider is supported by grant K01DA059329. Nathan B. Hansen is supported by the grants R01HD092185 and R34MH13256. The sponsors had no role in the design, analysis, or decision to publish these findings. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Haider MR, Karim S, Jayawardhana J, Hansen NB, Haile ZT. Association between state‐level medical marijuana legalization and marijuana use during pregnancy: a population‐based study. Am J Addict. 2025;34:75‐84. 10.1111/ajad.13651
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