One other study has utilized results from TAG to predict cannabis involvement in an independent sample. Vink and colleagues used polygenic scores created by aggregating SNPs at varying p-value thresholds, up to p = 0.5, to predict tobacco, alcohol and cannabis phenotypes in an independent Dutch sample. Such an approach has the advantage of utilizing effects, even those that are not statistically significant, to create a genetic predictor that is more consistent with the polygenic view of complex behavioral traits. The TAG polygenic scores for CPD were associated with CPD and cannabis use but the extent to which the most significant SNPs contributed to these findings is unclear. Our analyses studied these highly significant individual SNPs that were part of the polygenic scores and while we note a similar degree of association with rs1051730, we do not see any association with other TAG SNPs . We also extended the association to cannabis abuse/dependence, a phenotype that was not studied by Vink et al. . It is also worth noting that, for both tobacco smoking and cannabis involvement, SNPs associated with initiation were not associated with later stages of CPD or abuse/dependence. Prior twin analyses have suggested substantial overlap across genetic factors influencing initiation and problem use of both tobacco and cannabis . Nonetheless, evidence for genetic factors that only influence later stages of tobacco dependence have also been identified and is consistent with our results and those from the prior smoking meta-analyses . Some limitations of this study are worth noting. First, the evaluations focused only on European American subjects as the meta-analyses were restricted to similar samples. Second, these data did not have a quantitative “CPD-like” measure of cannabis use. Third, as the sample was enriched for alcohol dependence, rates of cigarette smoking and cannabis involvement are higher than those noted in the general population. This enrichment, particularly as one of the contributing samples was ascertained for nicotine dependence , may have influenced our ability to detect these associations. Importantly,grow rack the associations with cannabis involvement should be viewed as preliminary and pending replication.
In conclusion, while analyses revealed some promising relationships of SNPs previously implicated in tobacco smoking with cannabis measures, these associations did not appear to be independent of their effects on smoking. As large meta-analyses of tobacco smoking have shown, by increasing sample sizes, common variants associated with cannabis involvement can also be successfully identified. Such discoveries will enhance our ability to identify such cross-disorder SNPs with greater precision, as has been witnessed for phenotypes such as schizophrenia, bipolar disorder, major depressive disorder and autism .Previous literature shows a link between the passage of laws legalizing the use of cannabis for medical or recreational purposes and the possible effect on use rates, especially among youth. However, research into the impact of cannabis laws among pregnant women is limited. This study finds consistent associations of legalization of recreational cannabis is associated with cannabis use throughout the reproductive cycle; medical cannabis legalization was also associated with cannabis use, but only in the preconception period.These findings suggested legalization may play a role in cannabis use during pregnancy and providers may want to consider how and when the council pregnant women about substance use in states with legalization.In 1996, California became the first state to legalize cannabis for medical use and 28 other states have since followed suit, with eight also allowing recreational cannabis use . Today, cannabis is the most used illicit drug in the past year among all adults; 10–34% report use and among pregnant women 4–9% of report use . Cannabis use during pregnancy may have adverse effects on perinatal and child health outcomes including low infant birth weight and child mental health concerns . Moreover, the perception of harm of cannabis use among pregnant women may be decreasing along with legalization, given that some dispensaries “recommend” cannabis to pregnant women to alleviate pregnancy-related symptoms . Additionally, studies show that women who use cannabis during pregnancy are also more likely to use it in conjunction with tobacco, the most used substance during pregnancy.The concurrent use of two substances is a potentially dangerous combination since tobacco and cannabis use together is associated with an increased risk of adverse birth outcomes including stillbirth and small-for-gestational age when compared to using one substance alone.Researchers reported that low education levels, being unmarried, and using other substances all correlate with cannabis use, and very few studies examine state legalization status as a potential factor.
Studies of the general population and the limited studies including pregnant women show that cannabis legalization may affect patterns of substance use behavior and in recreationally legal states show a direct correlation between cannabis legalization and increased use of cannabis . Studies of pregnant women specifically found, those who use cannabis tend to enter prenatal care later and to use other substances along with cannabis, including tobacco . Importantly, these studies did not account for electronic cigarette use, even though studies show known health risks and use has increased markedly in the U.S. among pregnant women . Therefore, studies are needed that account for e-cigarette use when evaluating prenatal and postnatal concurrent tobacco and cannabis use. Furthermore, given the evolving cannabis policy in the U.S. and negative health impacts of both cannabis and tobacco on fetal and women’s health, current data specific to pregnant women that also account for state legalization status are crucial for advancing prenatal care and education. The current study was designed to address these gaps. Using the Pregnancy Risk Assessment Monitoring System survey, the sample included respondents from 16 states with varying types of cannabis legalization to: Examine the prevalence of cannabis use during the preconception, prenatal and postpartum periods Determine prevalence of co-occurring use of tobacco before and during pregnancy Identify factors associated with preconception, prenatal, and postpartum use of cannabis including state legalization status. We hypothesized that factors associated with cannabis use during the three time periods will be like those in the general population including a higher use among women living in states with recreational cannabis legalization. Additionally, we predicted women using cannabis would be more likely to co-use other substances, particularly, tobacco.The study is a secondary analysis of cross-sectional survey data collected in the 2016 through 2018 Pregnancy Risk Assessment Monitoring System by the Centers for Disease Control and Prevention and state health departments. Based on a stratifed sampling frame which selects from recent live births with complete birth certifcate data, the PRAMS survey is sent to pregnant women six weeks to three months post-partum throughout the United States as a way of monitoring perinatal health behaviors and experiences and their subsequent impact on infant health outcomes.
Comparison between states is possible through standardization of procedures and survey instruments. The sample for the current study included women 18 and older who provided an answer to the questions about cannabis use. Women under 18 were excluded due to the potential confounding factors associated with adolescent pregnancy and their lack of legal access to cannabis. The fnal sample included 36,391 women living in 16 states in the United States who were administered questions specific to cannabis use on the PRAMS survey and who gave birth between January 1st 2016 and December 31st 2018 for a weighted sample reflecting 15,486,000 women. Given the study design and possibility that women answered the survey for multiple pregnancies, prior to analysis we searched for duplicate participant identifiers and did not find repeat ids. Women agreed to participate in the survey with the knowledge and consent that the data may be used for scientific study . The study was reviewed and deemed exempt from further review by the University Institutional Review Board based on use of deidentified data. Therefore, the study was completed in accordance with the ethical standards in the 1964 Declaration of Helsinki and its later amendments.Individuals were classified either as cannabis users if they answered “yes” or nonusers if they answered “no” during three time periods: before pregnancy , during the last three months of pregnancy , and 6–12 weeks after delivery . Three prevalence outcomes were examined. Cannabis use during the last three months of pregnancy based on the question, “At any time during the last 3 months of your recent pregnancy, did you use marijuana or hash in any form”?; Cannabis use in the 12 months before pregnancy , based on the question, “At any time during the 12 months before your recent pregnancy, did you use marijuana or hash in any form”?; and cannabis use since delivery based on the question, “At any time during the 3 months since delivery,greenhouse grow tables did you use marijuana or hash in any form”? The final question regarding use after delivery was only asked in 8 of the 16 states analyzed .All analyses were conducted using Stata version 14 with PRAMS weights applied to account for the complex sampling design and generate estimates generalizable to pregnant women across the United States.
The PRAMS weights are determined by multiplying the sampling, non-response, and non-coverage of the weight yields and more detailed is available elsewhere . Less than 1% of respondents were missing data for any covariate; therefore, variables with missing data were imputed with the mode. All analysis was repeated with complete cases only with no substantive differences in the findings; results presented include imputed values. The prevalence of cannabis use was estimated in each of the three time periods . All socio-demographic and prenatal care characteristics were summarized and compared with chi-square tests for cannabis users and non-users during each time . Logistic regression was used to examine each cannabis use outcome as a function of state cannabis legalization status and the socio-demographic and health covariates. As a sensitivity analysis the three models were also repeated with clustering at the state-level, with no substantive differences to the reported results.In a large sample of pregnant women in 16 states, we contribute estimates of the prevalence of cannabis use in the preconception, prenatal and post-partum periods finding associations with use in recreationally legal states and some associations with residence in medically legal states. The rate of cannabis use before pregnancy reported here is consistent with nationally reported rates of 10.5% of the general population using cannabis but lower than recent rates of 34% in 2020, reported by the National Institute on Drug Abuse . To date, few studies include both recreational and medical cannabis legalization status as factors potentially influencing perinatal cannabis use.Studies that include legalization were typically limited to only one state and only addressed recreational legalization.Several factors could account for the state legalization status and association with use found in the study. First, as states legalize cannabis, women’s perception of harm of cannabis decreases, resulting in an increase in use rates as noted in the general population . To support this point, findings from a qualitative study where in-depth interviews were conducted found that 62% of women using cannabis reported that they would increase their use during pregnancy if cannabis was legalized . Similarly, another study found that women who used cannabis during pregnancy did not believe the substance harmful . Second, the opening of dispensaries following state legalization allows for better access to and promotion of cannabis use, possibly leading to use during pregnancy. In Colorado, a study of dispensaries found 69% recommended cannabis to the researcher who was claiming to be pregnant and asking for a recommendation on the use of cannabis during pregnancy . Future studies are needed to test the proposed mechanisms as drivers of use among pregnant women in recreationally legal states. The finding in this study of a higher odds of using cannabis during the preconception period in recreationally legal states and medically legal states are of particular concern given 45% of pregnancies in the United States are unplanned . In the cases of unplanned pregnancy, women using cannabis could unknowingly expose the embryo to cannabis derivatives like tetrahydrocannabinol during a critical period of fetal development. However, given that the preconception data for this study were collected up to twelve months before pregnancy to the study cannot accurately measure how close to conception women were using cannabis.