Perceptions about cannabis use during pregnancy: a rapid best-framework qualitative synthesis

Abstract

Objective

A rapid review was conducted in order to produce a streamlined and time-limited systematic evidence review to understand women’s perceptions, beliefs, and knowledge of the risks associated with cannabis use during pregnancy.

Methods

MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, EMBASE, PsycINFO (OVID interface), and CINAHL (Ebsco interface) databases were searched from inception to March 2019. Qualitative and descriptive studies, and reviews that addressed pregnant women’s perceptions, beliefs, and attitudes about personal cannabis use were included. The methodological quality of the included studies was appraised using valid tools and data extraction was guided by suitable checklists. Full text of 18 citations was retrieved and reviewed, and 5 studies met the inclusion criteria.

Synthesis

Women who continued to use cannabis during pregnancy often perceived less risk compared with nonusers. Their uncertainty regarding adverse consequences, perceived therapeutic effects, and lack of communication with health care providers contributed to cannabis use. Women perceived this lack of counselling as an indication that outcomes of cannabis use while pregnant were not significant.

Conclusion

This synthesis highlights important factors in women’s decision-making processes regarding use or cessation of cannabis during pregnancy. In addition, the importance of health care providers providing information, education, and appropriate counselling to childbearing women is highlighted as these conversations may influence women’s perceptions of risk and help them make informed choices.

Electronic supplementary material

The online version of this article (10.17269/s41997-020-00346-x) contains supplementary material, which is available to authorized users.

Introduction

Cannabis is the most frequently used substance during pregnancy in Canada (Porath et al. 2018). In 2017, the Canadian Tobacco, Alcohol, and Drugs Survey reported that 17% of Canadian women of childbearing age (15 to 44 years) disclosed past-year cannabis use (Government of Canada 2017). International studies report a prevalence rate of antenatal cannabis use between 2% and 5%, with much higher prevalence among younger, socio-economically disadvantaged women (15–28%; El Marroun et al. 2011; Passey et al. 2014). The relationship between cannabis use during pregnancy and adverse effects has been inconsistent and difficult to interpret due to a lack of consistent measures as well as multiple confounding variables.

Although there is no universal agreement regarding implications for pregnant women using cannabis, accumulating evidence suggests that cannabis exposure can have a detrimental impact on pregnancy and neonatal outcomes (Metz et al. 2017; Crume et al. 2018). Laboratory studies show that tetrahydrocannabinol (THC), cannabidiol (CBD), and other cannabinoids freely cross the placenta and permeate fetal tissues (Bailey et al. 1987), potentially disrupting fetal developmental pathways (Friedrich et al. 2016). In October 2018, the consumption, sale, and distribution of non-medicinal cannabis became legal in Canada for those over 18 years of age (Government of Canada 2018). In the United States, 33 states and the District of Columbia have passed laws legalizing marijuana (Washington, DC: Governing 2019). Concurrent with liberalization of cannabis, potency monitoring programs in the USA and Europe have reported a dramatic rise in THC concentration over the past 10 years (Chandra et al. 2019). The National Institute on Drug Abuse (NIDA) reported that the average THC content of cannabis products rose from 8.9% in 2008 to 17.1% in 2017 (Chandra et al. 2019). In addition, there are also cannabis use practices and products that can contribute to increased risk. Deep inhalation and regular inhalation of combusted cannabis can adversely affect respiratory health outcomes, and synthetic cannabinoids can produce acute and severe adverse health effects (Fischer et al. 2017).

As of October 17, 2019, cannabis edibles, extracts, and topicals also became legal in Canada. Whether edible cannabis is less harmful compared with smoked cannabis is debatable. The Centers for Disease Control and Prevention (Centers for Disease Control and Prevention 2018) cautions using any form of cannabis regardless of the mode of consumption (Crume et al. 2018; Budney and Borodovsky 2017). The combination of increased cannabis use, increased potency, and access to a variety of routes of administration poses an important public health and clinical practice challenge.

The American College of Obstetricians and Gynecologists (ACOG) and Society of Obstetricians and Gynaecologists of Canada (SOGC) recommend discontinuation of cannabis use during preconception, pregnancy, and lactation to prevent negative health outcomes for women, infants, and children (Society of Obstetricians and Gynaecologists of Canada 2017; American College of Obstetricians and Gynecologists Committee on Obstetric Practice 2015). Despite these warnings, women are using cannabis in greater numbers. For example, in Ontario, Canada, the overall prevalence of cannabis use in pregnancy increased from 1.2% in 2012 to 1.8% in 2017 (Corsi et al. 2019). Underlying reasons behind these trends are unclear; it may be that legalization has not only increased the availability of cannabis (Pacula et al. 2015) but also decreased the public’s perceptions of harm (Ko et al. 2015). It is imperative to understand women’s knowledge and perception of cannabis use to understand how they make decisions about cannabis consumption during pregnancy.

Despite recent guideline recommendations for abstinence, it is not understood why women continue to use cannabis while pregnant. We conducted a rapid review best-fit framework of published literature to describe women’s beliefs, perceptions, and assumptions about cannabis use. Our goal is to provide increased clarity around this issue and identify gaps in the literature. We will discuss areas for targeted interventions that may curb the incidence of cannabis use in pregnancy. These interventions will be discussed in light of the recent legalization of cannabis in Canada and recommendations to avoid cannabis use during pregnancy.

Methods

We used a best-fit framework synthesis to expedite systematic review methods (Booth and Carroll 2015). This approach offered the opportunity to test, reinforce, and build on existing published articles on maternal cannabis use during pregnancy. Our literature synthesis began with an a priori framework (Table 1) based on a recent integrated review of women’s perceptions of cannabis use during the perinatal period (Bayrampour et al. 2019), and a qualitative study exploring women’s beliefs and attitudes regarding prenatal cannabis use (Chang et al. 2019). We anticipated that our synthesis would generate content-specific dimensions and extend beyond our initial framework. We used the Enhancing Transparency in Reporting the synthesis of Qualitative Research (ENTREQ) statement for reporting (Tong et al. 2012).

Table 1.

A priori framework

Dimension
Background	History of use prior to pregnancy
Perceptions	Perceived benefits of cannabis use in the perinatal period—for the mother
	Perceived risk of harm using cannabis for developing fetus
	Perceived risk of harm using cannabis—long-term development of the child
Beliefs	Effective in treating nausea in pregnancy
	Marijuana is natural and safe
	Marijuana is not addictive
	Effective in managing anxiety/depression during the perinatal period
	Effective in managing sleep issues during the perinatal period
Assumptions	Internet-based sources of information
	Maternity care providers

Literature search

A rapid review was conducted and is reported in compliance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analysis) framework (Fig. 1). The literature search was conducted in Ovid MEDLINE, Ovid Medline (R), Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, EMBASE, PsycINFO (OVID interface), and CINAHL (Ebsco interface) and were searched from their inception to March 2019 (Supplemental Material). Our search is registered in PROSPERO (CRD42018107605). Only English-language articles on human subjects were included. Review papers, letters to the editor, animal studies, conference abstracts, book chapters, and duplicated studies were excluded. Non-formalized program evaluations, intervention studies, and systematic reviews were also excluded. We included human randomized controlled trials, qualitative and observational epidemiological studies, and reviews that addressed women’s perceptions, beliefs, and attitudes about cannabis use during pregnancy.

Fig. 1.

PRISMA 2009 flow diagram

Inter-reviewer agreement

Two reviewers (KSB and CR) independently reviewed abstracts to determine those eligible for full-text review and inclusion in the study. Prior to screening titles and abstracts, a calibration exercise was conducted of 10% of the titles and abstracts, with a 92% inter-rater agreement. Where disagreements occurred, the reviewers reviewed the inclusion criteria, discussed the merits of the study and why it did or did not warrant inclusion, and made decisions accordingly.

Quality assessment

We used the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool to assess quantitative studies based on six domains: selection bias, study design, confounders, blinding, data collection methods, and withdrawals/dropouts. Studies were not excluded based on quality. Each domain was assessed as strong, moderate, weak, or not applicable. Qualitative studies were assessed for aims, methodology, design, recruitment, data collection, researcher/participant relationship, ethical issues, data analysis, findings, and value using the critical appraisal skills program (CASP) qualitative checklist. These 10 domains were assessed as no, yes, or cannot tell. Two reviewers independently appraised the studies for methodological quality. Any discrepancies in quality appraisals were resolved through discussion.

Data extraction and synthesis

Data items were extracted using the Template for Intervention Description and Replication (TIDieR) and Transparent Reporting of Evaluations with Non-randomized Designs (TREND) checklists. We extracted the following for each study: study design, aim of study, sample description, type and history of cannabis use, and study findings. The results of studies were extracted into the a priori framework. Where data did not fit into the framework, data were synthesized using thematic analysis and additional themes were added to the framework as they became apparent. The a priori framework included the following categories: women’s perceived benefit to self, harm of cannabis use to fetus, reasons for continued use and effectiveness, perception that cannabis is natural and non-addictive, and assumptions based on information received from the Internet and health care providers. Two additional reviewers verified extracted data to ensure accuracy, and discrepancies were resolved by discussion within the team. Synthesis of the data was conducted according to the Cochrane handbook for systematic review guidance.

Results

In this rapid review, the initial database search yielded 3345 citations and added two additional records located in the two articles used to develop the a priori framework (Fig. 1). After removal of 1412 duplicates, 1933 titles and abstracts were selected for review. Of those titles and abstracts, 18 articles were eligible for full-text review. Based on the inclusion and exclusion criteria, 13 articles were excluded. We were unable to locate the full text for 1 article, 1 was a literature review, 1 did not discuss cannabis use, 1 addressed health care professionals’ attitudes, and 9 were commentaries or editorials rather than studies. In total, 5 studies that examined the perceptions, beliefs, and assumptions about cannabis use were selected for inclusion in the review (Table 2). These studies were published between 2015 and 2019. Data from the 2007–2012 National Surveys on Drug Use and Health in the USA comprised 4971 participants who identified as pregnant (Ko et al. 2015). Our synthesis also included research data from a probability-based online survey in which 16,280 American adults participated (Keyhani et al. 2018). Mark et al. (2017) interviewed predominately young African-American (81%) women in their 20s (mean 25.9 years), living with low socio-economic status (SES) (N = 306). Two qualitative studies were conducted with the same cohort of 26 women (mean age 26 years) who were predominately African-American (73%), and living with lower SES (Chang et al. 2019; Jarlenski et al. 2016).

Table 2.

Study characteristics

Study	Location	Design	Sample	Perception/beliefs/attitudes
Chang et al. 2019	Five clinical settings in Pittsburg, USA	Qualitative, part of a larger observational study	25 pregnant women who either reported or tested positive for cannabis	Pregnant women who used cannabis during pregnancy reported trying to reduce usage and were worried about associated risks, but also believed cannabis to be natural and safer than other substances, including prescribed medication.
Jarlenski et al. 2016	Five clinical settings in Pittsburg, USA	Qualitative, part of a larger observational study	26 pregnant women who either reported or tested positive for cannabis	Internet and anecdotal experiences or advice from family and friends were the most commonly reported sources of information. Most women reported they did not receive helpful information from health care professionals, which implied perinatal cannabis use was not a serious risk. Most women reported a desire for more information about the effects of perinatal cannabis use on infant health.
Keyhani et al. 2018	National survey (USA)	National probability-based online survey in 2017	Respondents (n = 9003) of whom 52% were female with the mean age of 48 years	81% of respondents believe cannabis to have at least one health benefit, 92.1% agree using cannabis during pregnancy is completely or somewhat unsafe, and 22.4% believe cannabis to be not at all addictive.
Ko et al. 2015	National Survey on Drug Use and Health data from 2002 through 2012 (USA)	Time-trend analysis of cross-sectional data	Pregnant (n = 4971) and nonpregnant (n = 88,402) women 18–44 years of age	Almost 70% of both nonpregnant and pregnant past-year cannabis users perceived a slight or no risk from using cannabis once a month or once or twice a week.
Mark et al. 2017	An outpatient prenatal clinic at the University of Maryland Medical Center in Baltimore, USA, between 2015 and 2016	Cross-sectional	306 pregnant women with average age of 25.9 years and predominately African-American (81%)	70% of participants reported believing cannabis could be harmful to a pregnancy. Among respondents who continued to use cannabis during pregnancy, 96% reported they did so to treat nausea.

Quality appraisal

Overall, the studies were rated moderate in quality. A weak rating was identified in at least one of the eight areas of the EPHPP (selection bias, study design, confounders, blinding, data collection methods, withdrawals/dropouts, intervention integrity, and analysis). The summary of the rating of individual items of the EPHPP tool is reported in Table 3 and for the CASP, in Table 4.

Table 3.

Quality appraisal for quantitative studies

Study	Selection bias	Study design	Confounders	Blinding	Data collection methods	Withdrawals/dropouts	Intervention integrity	Analysis	Overall rating
Keyhani et al. (2018)	Weak	Weak	Weak	Weak	Moderate	N/A	N/A	Moderate	Weak
Ko et al. (2015)	Weak	Moderate	Moderate	Moderate	Strong	N/A	N/A	Strong	Moderate
Mark et al. (2017)	Weak	Weak	Moderate	Moderate	Moderate	N/A	N/A	Moderate	Weak

Table 4.

Quality appraisal for qualitative studies

Study	Research aim	Methodology	Research design	Recruitment	Data collection	Research reflexivity	Ethical issues	Analysis and rigour	Clear findings	Value	Overall rating
Chang et al. (2019)	Yes	Yes	Yes	Cannot tell	Yes	Cannot tell	Cannot tell	Cannot tell	Yes	Yes	Moderate
Jarlenski et al. (2016)	Yes	Yes	Yes	Yes	Yes	No	Cannot tell	Yes	Yes	Yes	Moderate

Dimensions of the a priori framework

Data from the five studies reported in this review are supported by the a priori framework and synthesized in Table 5. No new dimensions were identified from the initial framework. We proceeded with our review to explore maternal perceptions, attitudes, and beliefs about cannabis use during pregnancy.

Table 5.

A priori framework results

Author	Perceptions	Beliefs	Assumptions based on source of information
Chang et al. 2019	Perceived benefits: Manage stress, improve mood, and treat pregnancy-related nausea, vomiting, and appetite changes Perceived risk: Risk to developing fetus – may restrict oxygen flow to the fetus Risk to child development – may cause respiratory problems, immune disorders, or delayed brain development	Effective in treating nausea – yes Effective and safe – yes Not addictive – yes Effective in managing anxiety/depression – yes Effective in managing sleep issues – not mentioned	Internet-based sources – not mentioned Maternity care providers – not mentioned *All women described a desire for more information
Jarlenski et al. 2016	Perceived benefits: Not mentioned Perceived risk: Risk to developing fetus – non-specific harms Risk to child – not mentioned *Not concerned about their own health outcomes	Effective in treating nausea – not mentioned Effective and safe – not mentioned Not addictive – not mentioned Effective in managing anxiety/depression – not mentioned Effective in managing sleep issues – not mentioned	Internet-based sources – searched on Facebook and Google Maternity care providers – lack of discussions, inadequate resources, punitive communication was common
Keyhani et al. 2018	Perceived benefits: 81% believe that there is at least one benefit Perceived risk: Risk to developing fetus – 7.3% somewhat or completely safe in pregnancy Risk to child development – same as second-hand smoke	Effective in treating nausea – not mentioned Effective and safe – not mentioned Not addictive – 22.4% say not addictive Effective in managing anxiety/depression – 46.8% agree Effective in managing sleep issues – not mentioned	Internet-based sources – not mentioned Maternity care providers – not mentioned
Ko et al. 2015	Perceived benefits: – Not mentioned Perceived risk: Risk to developing fetus – not mentioned Risk to child development – not mentioned *70% of users believe slight to no risk if using once a month	Effective in treating nausea – not mentioned Effective and safe – not mentioned Not addictive – not mentioned Effective in managing anxiety/depression – not mentioned Effective in managing sleep issues – not mentioned	Internet-based sources – not mentioned Maternity care providers – not mentioned
Mark et al. 2017	Perceived benefits: 96% used for nausea Perceived risk: Risk to developing fetus – 70% Risk to child development – motivation to quit using	Effective in treating nausea – 96% Effective and safe – not mentioned Not addictive – not mentioned Effective in managing anxiety/depression – not mentioned Effective in managing sleep issues – not mentioned	Internet-based sources – not mentioned Maternity care providers – 27% were instructed to quit or reduce use in pregnancy

Cannabis use

The prevalence of cannabis use among women varied significantly across the included studies. A large population-based study found that rates of past month use and past 2–12 month use among pregnant women were 3.9% and 7.0% respectively (Ko et al. 2015). Higher prevalence of use was reported among ethnic minorities and those of a younger age with lower SES. For example, in a sample of 306 predominately African-American young women (mean age 25.9 years), 35% of survey respondents were current cannabis users at the time of pregnancy and 11% continued to use during pregnancy (Mark et al. 2017). Almost all women who used cannabis during pregnancy reported using higher amounts of cannabis prior to pregnancy and reducing consumption during their pregnancies (Chang et al. 2019; Mark et al. 2017). Similarly, women who continued to use cannabis during pregnancy had the highest use during the first trimester (7.4%) and lowest in the third trimester (1.8%; Ko et al. 2015).

Perceived benefits of cannabis use

Two studies examined motivations for continued cannabis use during pregnancy. Women chose to continue using based on perceived benefit in treating appetite changes, nausea, and vomiting related to pregnancy, and to manage mood and increase ability to cope with daily stressors (Mark et al. 2017; Chang et al. 2019). It was not clear whether cannabis was prescribed or recommended by physicians or whether women self-prescribed or substituted cannabis for other medications (Mark et al. 2017; Chang et al. 2019). One study found that 96% of pregnant women who used cannabis were self-medicating for pregnancy-induced nausea (Mark et al. 2017). Anecdotal experiences of family and friends that claimed benefits of perinatal cannabis use were also major contributors to women’s beliefs that cannabis use could be beneficial during pregnancy (Jarlenski et al. 2016).

Perceived harm of cannabis use to fetus

A probability-based survey of adult Americans found that 7.3% of respondents agreed that cannabis use is somewhat or completely safe during pregnancy (Keyhani et al. 2018). In a study including only pregnant women, 30% of respondents reported that they did not believe cannabis to be harmful to a baby during pregnancy (Mark et al. 2017). In contrast, qualitative interviews revealed that pregnant women thought that cannabis use might introduce health risks (Jarlenski et al. 2016). These women stated that their decisions focused almost solely on the well-being of the baby. They also reported uncertainty regarding the specific health risks, a lack of information about explicit harms to the fetus, and uncertainty of a causal relationship between cannabis consumption and perinatal health outcomes (Jarlenski et al. 2016). The perceived lack of information regarding risk of perinatal cannabis use was compared with known risks of substances including tobacco and other recreational drugs. Women stated that information about the effects of tobacco and alcohol on infant health and fetal development was clear, while such information regarding the effects of cannabis was contradictory (Jarlenski et al. 2016), and this led women to believe tobacco or alcohol could be more dangerous in pregnancy than cannabis (Chang et al. 2019).

Perceived harm of cannabis use on children’s long-term outcomes

Women agreed there was limited information available regarding specific risks to infant development and later childhood outcomes (Chang et al. 2019; Jarlenski et al. 2016; Harris and Okorie 2017). Throughout our review, we found women expressed a need for more accurate information, and when asked to speculate on the possibility of long-term childhood outcomes, responses varied from immune disorders such as eczema, to asthma, or delayed brain development. Women agreed that the information they received was often conflicting and they were not clear as to whether perinatal cannabis use affected childhood health outcomes (Jarlenski et al. 2016). In comparison women stated they were aware of the impact that alcohol and tobacco potentially has on childhood outcomes (Jarlenski et al. 2016).

Perceived benefits of cannabis for nausea

Most women who continued to use cannabis during pregnancy did so because they believed it was helpful for decreasing nausea, anxiety, and depression. Among pregnant women who quit using, 31% reported that they had used cannabis early in pregnancy to treat nausea (Mark et al. 2017). Women justified use to treat nausea as it was their perception that poor maternal nutritional intake posed greater harm to the baby than exposure to cannabis in utero (Chang et al. 2019). Qualitative interviews showed that women felt more able to cope with daily stressors when consuming cannabis (Chang et al. 2019). Some individuals also preferred using cannabis to treat depression, rather than psychotropic medications prescribed by their family physician. Studies do not clearly state whether cannabis use was discussed with their physician or if it was self-prescribed and used in addition to other medications suggested by physicians. Women viewed cannabis as “natural” and prescribed medications as “chemicals” that had known side effects and often were not as effective in managing their symptoms as cannabis. There was an overall sense for many women that cannabis was not only more effective but also a safer and preferable option for treating various conditions during pregnancy (Chang et al. 2019).

Perceptions of cannabis as natural and safe

Cannabis is consistently seen as “natural” and therefore harmless. Women perceive cannabis as an ordinary, healthy plant, therefore less noxious than other recreational drugs and prescribed medications (Chang et al. 2019). Interestingly, women saw tobacco as a more toxic substance than cannabis even though it is also a naturally occurring plant. This perception was supported by the fact that women were well educated regarding the negative consequences of tobacco use during pregnancy and were unaware of specific risks related to cannabis (Chang et al. 2019).

Perceptions of cannabis as not addictive

Women are divided on their opinions as to whether cannabis is addictive (Chang et al. 2019). They believe that they can quit cannabis without difficulty, at any time, supporting the assumption that cannabis is safe, natural, and not a drug. These varied opinions are also found in a US national survey where 76% of US adults agree that cannabis is somewhat or very addictive, while 22.4% believe it is not addictive at all (Keyhani et al. 2018).

Assumptions based on source of information

Women identified the Internet as their main source of information about cannabis use in pregnancy. The information women retrieved made clear the public debate about whether cannabis was beneficial or harmful for pregnant women or their fetus (Jarlenski et al. 2016). Overall, women felt that the information available was inconsistent and it often juxtaposed anecdotal experiences of family or friends, leaving women feeling conflicted in their decision-making.

Despite being actively engaged with their health care providers, most pregnant women reported they did not receive helpful information about cannabis use. The lack of counselling around potential harms led women to the implication that perinatal cannabis use was not a serious risk (Jarlenski et al. 2016). Communication with health care providers was predominately focused on punitive measures rather than providing information and resources to facilitate informed decision-making during pregnancy (Jarlenski et al. 2016).

Discussion

In this rapid review, we explore women’s beliefs, assumptions, and perceptions about cannabis use during pregnancy. There is an absence of clear evidence of harm to childbearing women who use cannabis. The scientific literature is mixed due to predominately retrospective cohorts that rely on self-reporting of cannabis exposure, failure to adjust for important confounding factors such as tobacco use and socio-demographic factors, and a lack of standardized measurement outcomes (Gunn et al. 2016; Metz and Borgelt 2018). In light of contradictory evidence and lack of open discussion with health care providers about potential harms, many pregnant women are left to manage decisions around cannabis use on their own (Jarlenski et al. 2016). Public health messaging is primarily focused on risk to the fetus, the developing brain, and breastfeeding infant, but giving no definitive proof that cannabis use will result in poor outcomes for women or their infants. In contrast, cannabis producers and regular users espouse the benign or beneficial consumption of this “natural” product with equally lean scientific evidence. Women’s perceptions and assumptions are founded and rooted in their own critical appraisal of often contrasting information, often complicated by mental health and addiction challenges (Kearney 1998).

Cannabis use in the US population has doubled in the past decade (Keyhani et al. 2018), and 24.9% of both pregnant and nonpregnant US women of reproductive age reported cannabis use in the past year (Ko et al. 2015). In Canada, increasing cannabis use is also an important public health issue, particularly as 61% of Canadian pregnancies are unintended (Society of Obstetricians and Gynaecologists of Canada 2017). In the USA, most unintended pregnancies occur among women of lower income and younger age (Finer and Zolna 2014), which include those who are more likely to use cannabis (Ko et al. 2015). A Canadian population-based retrospective cohort study found that the lowest two income quintiles accounted for more than half (55%) of the population of cannabis users. The prevalence of prenatal cannabis use was highest among women aged 15–24 years, and this age group was significantly more likely to use cannabis in pregnancy. Among women who reported cannabis use in pregnancy, the majority (52%) were aged 15–25 years (Corsi et al. 2019). Current literature suggests that a significant proportion of cannabis users quit or decrease their consumption during pregnancy (Singh et al. 2019; Ko et al. 2015), but there are no validated methods of measuring dosing and quantity of cannabis consumption, putting this suggestion into question.

Perceptions and beliefs

Many women acknowledge that cannabis could be harmful to their pregnancy or infant, however cannot identify potential harms. For example, 30% of pregnant women attending a prenatal care clinic reported that cannabis was not detrimental to their pregnancy (Mark et al. 2017). These perceptions may be due to the current scientific uncertainty of the causal relationship between cannabis consumption and health outcomes in pregnancy and postpartum (Volkow et al. 2014).

Cannabis is commonly used in the treatment of chemotherapy-induced nausea (Tramer et al. 2001), and may be a reason why pregnant women rationalize its use as an anti-nausea medication in early pregnancy. A survey among pregnant women in British Columbia, Canada, reported their using cannabis to treat nausea; 93% deemed it “extremely effective” or “effective” for their symptoms (Westfall et al. 2006). Similarly, women described using cannabis for symptoms associated with stress, anxiety, and depression as preferable to the “chemicals” in prescribed medication (Chang et al. 2019). The preference of cannabis over prescribed pharmaceuticals could be explained by the fact that women often frame the safety of cannabis with comparisons with known and perceived risks of other substances and medications. More effective clinical communication and public health messaging is needed to disseminate what is currently known about cannabis use in pregnancy and lactation. Investigating barriers to these processes is warranted given the growth in cannabis marketing campaigns (McGinty et al. 2016; Abraham et al. 2018) that promote cannabis use for reasons not currently supported by the SOGC (Society of Obstetricians and Gynaecologists of Canada 2017). There is a significant gap in the literature about the safety and risks of cannabis use in pregnancy, postpartum, and breastfeeding.

Assumptions

Childbearing women’s perception that cannabis is safe may be exacerbated by lack of communication between health care providers and their patients about potential risk (Jarlenski et al. 2016). Qualitative data show that during prenatal visits some women disclose cannabis use to a health care provider; however, nearly half of providers do not offer counselling or respond to the disclosure. When counselling is provided, it consists mainly of general statements without specific risks or outcome data, and focuses on possible punitive actions (Holland et al. 2016). Research suggests that women have a desire for information regarding the effects of perinatal cannabis use and when they seek professional guidance, they do not feel satisfied with the information they receive (Jarlenski et al. 2016). Many health care providers do not have adequate knowledge about cannabis to counsel pregnant women confidently. It is imperative that health care providers have open, evidence-informed conversations with their clients regarding cannabis use to assist in decision-making and effective treatment when appropriate.

The perceived lack of counselling may be related to lack of robust information regarding risks cannabis consumption poses to women who are pregnant, or the fact that practitioners, along with the public, have relatively favourable attitudes towards cannabis as compared with other drugs (Holland et al. 2016). This review highlights the importance of how a collaborative, trusting relationship between patient and health care provider can contribute to women’s decision-making processes surrounding abstention or decreasing cannabis consumption. There is a compelling need to investigate knowledge and beliefs regarding cannabis use of both pregnant and lactating patients as well as health care providers. There is also a need to understand the barriers encountered in the patient/health care provider counselling process to tailor effective communication and inform training resources.

An Australian study explored messaging that would promote abstinence from alcohol during pregnancy and may be helpful in guiding conversations with women about cannabis use. The researcher found that many women were aware that abstinence was recommended, but were skeptical regarding the risk associated with low to moderate alcohol use (France et al. 2013). When health care providers engaged in open conversations about the limitations in the current scientific knowledge about alcohol use, participants perceived this communication as honest and it enhanced the credibility of the overall recommendation of abstinence. Threat-based messaging and sensationalizing risks may decrease the persuasiveness of recommendations (France et al. 2013). In light of this research, health care providers could provide factual information, and support women to think critically about the current ambiguity of evidence related to harms from perinatal cannabis use. Women’s self-efficacy in the decision-making process can add to health care providers’ credibility when discussing the current uncertainty of fetal and long-term risks of cannabis use during pregnancy and lactation (France et al. 2013).

There are limited data that differentiate between cannabis use in pregnancy and breastfeeding. In Canada, the prevalence of use during lactation, infant exposure through breastmilk, and associated infant outcomes are poorly understood (Committee on Obstetric Practice 2017; Metz and Borgelt 2018). A recent literature review of cannabis use during lactation found a strong correlation between prenatal and post-natal cannabis use; 84% of women reported consuming cannabis during pregnancy and during lactation (Ordean and Kim 2020). We draw attention to the critical need for research in this area to support effective public health messaging and counselling not only during pregnancy but also during lactation.

Limitations

This review is not without limitations. Evidence regarding women’s perceptions and knowledge of perinatal cannabis use is evolving as noted in our methodological quality appraisal. Our results may be limited by not including non-English-language research papers. All of the articles included in this rapid review were published in the USA, and two studies contained the same cohort of participants (Chang et al. 2019; Jarlenski et al. 2016). Some caution may be advised in interpreting the findings given the limited population. Despite the data overlap between these studies, we included both in our review as they examined different aspects of women’s perceptions and offered valuable insights for discussion. This review also notes that there was no examination of consumption patterns or exposure-outcomes results.

Investigating women’s perceptions with increased diversity in socio-economic, geographical locations, and visible minority may yield different results. Convenience samples of predominately urban women of African-American descent and of low SES were used in three of the studies (Jarlenski et al. 2016; Chang et al. 2019; Mark et al. 2017), yet no studies with white, middle-class participants. Two studies used data from national surveys in the USA during 2002–2017 when cannabis remained illegal in many states. The response rate and willingness to disclose cannabis use may be different in legalized jurisdictions. Research participants’ mode of cannabis consumption and dosing is also inconsistently reported in the literature. Prospective research would benefit from development of an accurate tool for clinicians and scientists to more accurately assess and perhaps categorize use into mild, moderate, or heavy to differentiate most-at-risk populations and accurately study outcomes. Finally, there is a paucity of research exploring specific THC and CBD content and methods of consumption in childbearing women. The limitations identified here are evidence that high-quality research is essential to better understand how childbearing women make decisions about using cannabis.

Conclusion

The prevalence of cannabis use during pregnancy has increased over the last decade and its perceived safety in both the general and pregnant populations is also increasing. Women’s perspectives and knowledge regarding the health benefits or risks of perinatal cannabis are important factors in their decision-making process to abstain or continue use. Women report a lack of useful communication with health care providers regarding the health effects of perinatal cannabis use. More comprehensive discussions are needed to support informed choices and guide counselling. Understanding pregnant women’s and health care providers’ perceptions of risk and effectiveness of cannabis use during pregnancy, in the absence of clear evidence and in the changing legal and societal environment, is imperative for successful development of patient education, counselling strategies, appropriate public health messaging, and policy.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.