Prevalence and outcomes of prenatal recreational cannabis use in high-income countries: a scoping review

Association of Recreational Cannabis Legalization With Maternal Cannabis Use in the Preconception, Prenatal, and Postpartum Periods

IMPORTANCE

Recent studies have revealed increases in population-level cannabis use after legalization of recreational cannabis. However, the association of cannabis legalization with maternal cannabis use during important life stages remains unknown.

OBJECTIVE

To investigate the association of legalization of recreational cannabis with maternal cannabis use during the preconception, prenatal, and postpartum periods.

DESIGN, SETTING, AND PARTICIPANTS

This repeated cross-sectional study used state-level data on women who delivered live-born infants in the US from the Pregnancy Risk Assessment Monitoring System from January 2004 to December 2018. Data from 2 states that had legalized recreational cannabis (Alaska and Maine) and 2 states that had not legalized recreational cannabis (New Hampshire and Vermont) were used. Women completed surveys 2 to 6 months after delivery, reporting preconception, prenatal, and postpartum cannabis use.

EXPOSURE

State recreational cannabis legalization.

MAIN OUTCOMES AND MEASURES

The 3 primary outcomes were self-reported cannabis use during the 12 months before pregnancy (preconception), during pregnancy (prenatal), and the 2 to 6 months after pregnancy (postpartum). A difference-in-differences analysis was used to compare changes in the prevalence of maternal cannabis use during each period before and after state legalization of recreational cannabis, controlling for maternal characteristics (age, race/ethnicity, educational level, income, cigarette smoking, and breastfeeding) and state fixed effects. State-specific survey weights were used.

RESULTS

The analytic sample included 23 082 women in the preconception period, 23 859 in the prenatal period, and 26 610 in the postpartum period. In each analysis, most women were married (range among all groups, 63.9%-64.8%), aged 25 to 34 years (preconception, 55.4%; prenatal, 55.9%; postpartum, 56.1%), and had an annual household income less than $50 000 (preconception, 55.7%; prenatal, 56.3%; postpartum, 55.5%). In adjusted analyses, preconception and postpartum cannabis use increased significantly in states that had legalized recreational cannabis compared with states that had not legalized it (preconception risk difference, 0.0457 [95% CI, 0.0013-0.0900]; P = .04; postpartum risk difference, 0.0539 [95% CI, 0.0259-0.0818]; P < .001). The risk difference for prenatal cannabis use was not significant (0.0070; 95% CI, -0.0120 to 0.0260; P = .47).

CONCLUSIONS AND RELEVANCE

In this repeated cross-sectional study, recreational cannabis legalization was associated with changes in maternal cannabis use before and after pregnancy. The findings suggest that future studies should undertake an interdisciplinary approach to maximize benefit and application of findings to future public health, health care, and policy sectors.

Gestational exposure to Δ9-THC impacts ovarian follicular dynamics and angiogenesis in adulthood in Wistar rats

With the legalization of marijuana (Cannabis sativa) and increasing use during pregnancy, it is important to understand its impact on exposed offspring. Specifically, the effects of Δ-9-tetrahydrocannabinol (Δ9-THC), the major psychoactive component of cannabis, on fetal ovarian development and long-term reproductive health are not fully understood. The aim of this study was to assess the effect of prenatal exposure to Δ9-THC on ovarian health in adult rat offspring. At 6 months of age, Δ9-THC-exposed offspring had accelerated folliculogenesis with apparent follicular development arrest, but no persistent effects on circulating steroid levels. Ovaries from Δ9-THC-exposed offspring had reduced blood vessel density in association with decreased expression of the pro-angiogenic factor VEGF and its receptor VEGFR-2, as well as an increase in the anti-angiogenic factor thrombospondin 1 (TSP-1). Collectively, these data suggest that exposure to Δ9-THC during pregnancy alters follicular dynamics during postnatal life, which may have long-lasting detrimental effects on female reproductive health.

Perceived Risk of Weekly Cannabis Use, Past 30-Day Cannabis Use, and Frequency of Cannabis Use Among Pregnant Women in the United States

BACKGROUND

While accumulated evidence has shown that the prevalence of cannabis use among pregnant women in the US has increased in recent years, little is known about the specific subpopulations affected. The aim of this study was to estimate the prevalence and correlates of the perceived risk of weekly cannabis use, past 30-day cannabis use, and frequency of past 30-day cannabis use among US pregnant women.

METHODS

We analyzed data from 2,247 pregnant women 14 to 44 years of age surveyed in the 2015 to 2017 cross-sectional National Survey on Drug Use and Health. Analyses account for the sampling design. Primary outcomes included perceived risk of weekly cannabis use, past 30-day cannabis use, and frequency of cannabis use. We conducted multivariable logistic and negative binomial regression models to assess the associations between the primary outcomes and multiple correlates.

RESULTS

Among US pregnant women, 21.6% (95% CI=19.4, 23.8) did not perceive any risk associated with weekly cannabis use, 5.3% (95% CI=4.2, 6.5) used cannabis in the past 30 days, and among past-month users, the average number of days of use was 15.6 (95% CI=13.5, 17.7). Pregnant women living below the poverty line were both more likely to perceive no risk of weekly cannabis use (aOR=1.8; 95% CI=1.3, 2.5) and use cannabis more often in the past 30 days (aOR=2.9; 95% CI=1.5, 5.7) than pregnant women within an income bracket of more than two times the federal poverty threshold. Age, race, trimester of pregnancy, co-use of tobacco and/or alcohol were also associated with these outcomes.

CONCLUSION

Younger age, living in poverty, early trimester of pregnancy, and co-use of tobacco and/or alcohol increased the odds of cannabis use among pregnant women. As cannabis legalization spreads and cannabis use is increasingly perceived as safe, there is a growing need for research to determine the reasons why women in the identified at-risk subgroups are using cannabis during pregnancy.

Update on the developmental consequences of cannabis use during pregnancy and lactation

There is a strong increase in prevalence trends for cannabis use during pregnancy and lactation as more states legalize use of this drug. Information on the teratogenic risk of cannabis is limited but some important themes can be gleaned. Studies have not found a unique phenotypic signature of prenatal exposure but an increased risk of congenital anomalies, particularly gastroschisis, has been reported. Changes in fetal growth have been described in some epidemiological studies but long-term patterns of physical growth appear unaffected. Prenatal exposure to cannabis is not generally associated with reductions in global IQ but specific cognitive skills, especially attention and memory, can be negatively impacted. Long-term impacts on psychological health include increased rates of depressive symptoms and anxiety as well as delinquency. Relatively little is known about the risk of maternal cannabis use during lactation but data suggest that infant exposure is relatively low compared to maternal exposure. As delta-9-tetrahydrocannabinol (THC) levels increase to meet consumer demand and routes of exposure diversify, there is a strong need for prospective birth-cohort studies that collect biological samples to quantify exposure. Data from such studies will be critical to overcoming the weaknesses of past cannabis research and are essential to establishing reliable information on the risks of maternal use. Until that time, health care providers should be encouraged to talk about the risks and benefits associated with cannabis use during pregnancy and lactation with their patients, emphasizing that fetal and neonatal risks cannot be excluded at this time.

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

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.

Prenatal Cannabinoid Exposure: Emerging Evidence of Physiological and Neuropsychiatric Abnormalities

Clinical reports of cannabis use prevalence during pregnancy vary widely from 3% to upwards of 35% in North America; this disparity likely owing to underestimates from self-reporting in many cases. The rise in cannabis use is mirrored by increasing global legalization and the overall perceptions of safety, even during pregnancy. These trends are further compounded by a lack of evidence-based policy and guidelines for prenatal cannabis use, which has led to inconsistent messaging by healthcare providers and medically licensed cannabis dispensaries regarding prenatal cannabis use for treatment of symptoms, such as nausea. Additionally, the use of cannabis to self-medicate depression and anxiety during pregnancy is a growing medical concern. This review aims to summarize recent findings of clinical and preclinical data on neonatal outcomes, as well as long-term physiological and neurodevelopmental outcomes of prenatal cannabis exposure. Although many of the outcomes under investigation have produced mixed results, we consider these data in light of the unique challenges facing cannabis research. In particular, the limited longitudinal clinical studies available have not previously accounted for the exponential increase in (-)-Δ9- tetrahydrocannabinol (Δ9-THC; the psychoactive compound in cannabis) concentrations found in cannabis over the past two decades. Polydrug use and the long-term effects of individual cannabis constituents [Δ9-THC vs. cannabidiol (CBD)] are also understudied, along with sex-dependent outcomes. Despite these limitations, prenatal cannabis exposure has been linked to low birth weight, and emerging evidence suggests that prenatal exposure to Δ9-THC, which crosses the placenta and impacts placental development, may have wide-ranging physiological and neurodevelopmental consequences. The long-term effects of these changes require more rigorous investigation, though early reports suggest Δ9-THC increases the risk of cognitive impairment and neuropsychiatric disease, including psychosis, depression, anxiety, and sleep disorders. In light of the current trends in the perception and use of cannabis during pregnancy, we emphasize the social and medical imperative for more rigorous investigation of the long-term effects of prenatal cannabis exposure.