Cannabis Use in Pregnancy and Neonatal Outcomes: A Systematic Review and Meta-Analysis

Transgenerational effects of perinatal cannabis exposure on female reproductive parameters in mice

The use of cannabis during pregnancy and nursing is a growing public health concern, and the multigenerational impacts of perinatal cannabis exposure remain largely unknown. To address this knowledge gap, we sought to examine the long-term consequences of perinatal cannabis use on reproductive function and how it might impact subsequent generations. Pregnant female mice were exposed to control vehicle or cannabis extract [25, 100, or 200 mg/ml Δ9-tetrahydrocannabinol (THC) in the cannabis extract] from gestational day 1 to postnatal day 21 (twice/day), encompassing the duration of pregnancy through weaning. Based on plasma THC concentrations in F0 females, we chose 100 and 200 mg/ml THC in the cannabis extract for subsequent studies. The selected doses and exposure conditions did not disrupt pregnancy or nursing in F0 females. Pregnancy and neonatal outcomes, including gestational length, litter size, and sexual ratio, were not affected by cannabis exposure. However, cannabis-exposed neonatal F1 pups were smaller. Cannabis exposure delayed vaginal opening as a sign of puberty onset and disrupted estrous cyclicity in F1 females. However, its effects were minor in F2 and F3 females. F1-F3 females showed no abnormal ovarian and uterine histology or plasma estradiol-17β levels and could produce normal offspring without pregnancy issues. These results suggest that the developmental stages of the hypothalamus and pituitary are likely perturbed by gestational and nursing cannabis exposure in F1 females. However, they are not sufficient to compromise adult reproductive function. The present results indicate limited transgenerational effects of perinatal cannabis exposure on female reproductive parameters.

Prenatal cannabinoid exposure and the developing brain: Evidence of lasting consequences in preclinical rodent models

Cannabis use by people who are pregnant is increasing. Understanding how prenatal cannabinoid exposure (PCE) affects infants and children is of high public health significance. Epidemiological studies have associated PCE with cognitive symptoms, including impaired learning, memory, attention, and executive control, and affective symptoms, including anxiety, emotional dysregulation, and social impairments, in children, adolescents, and young adults. PCE is also associated with neurobiological changes including decreased corticolimbic white matter and functional connectivity; however, the underlying mechanisms for these persisting effects remain unknown. Rodent models are essential for uncovering the effects of PCE on the developing brain. This review summarizes rodent studies focused on the cognitive and affective behavioral and neurobiological outcomes of PCE. Rodent studies have reported cognitive deficits, including impaired learning, memory, attention, and executive control, and affect-related impairments, including anxiety-like behavior, altered stress coping, social impairments, and anhedonia-like behavior, in adolescent and adult offspring. Studies have also demonstrated that PCE affects several underlying neurotransmitter systems, producing dopamine hyperactivity, glutamate and serotonin hypoactivity, and dysregulating GABA and opioid signaling. Evidence further suggests a marked difference in outcomes between males and females, with males being more susceptible to the enduring effects of PCE. However, studies that investigate female-specific outcomes or sex as a biological variable are scarce. Altogether, rodent studies provide corroborating evidence that PCE produces lasting cognitive and affective impairments underpinned by altered neurobiological mechanisms. Research is critically needed to improve our understanding of the risks associated with cannabis use during pregnancy and effects across the lifespan.

Prenatal Cannabis Use and Neonatal Outcomes: A Systematic Review and Meta-Analysis

Importance

Prenatal cannabis use continues to increase, and cannabis remains the most commonly used illegal substance in pregnancy. Accumulating evidence suggests potential adverse effects on fetal and neonatal outcomes following cannabis use in pregnancy.

Objective

To update a living systematic review and meta-analysis to provide a timely understanding regarding cannabis use in pregnancy and fetal and neonatal outcomes.

Data Sources

The previous review was updated by searching bibliographic databases MEDLINE, CINAHL, PsycInfo, Global Health, and Evidence-Based Medicine Reviews Cochrane Database of Systematic Reviews from November 1, 2021, through April 4, 2024.

Study Selection

Cohort or case-control studies comparing pregnancies with and without prenatal cannabis use on prespecified fetal or neonatal outcomes with adjustment for confounders, such as co-use of tobacco products, were included. Two independent reviewers screened studies, with disagreements resolved through discussion.

Data Extraction and Synthesis

Included studies were extracted by 1 reviewer and confirmed by a second. Risk of bias was assessed with the Newcastle-Ottawa Scale. Random-effects meta-analyses of unadjusted and adjusted odds ratios (ORs) were performed for all primary outcomes. Results were synthesized using the Grading of Recommendations Assessment, Development, and Evaluation approach.

Main Outcomes and Measures

Primary outcomes were preterm birth (PTB; <37 weeks of gestation), small for gestational age (SGA), low birth weight (LBW; <2500 g), and perinatal mortality.

Results

For this update, 8 new studies with 1 709 998 participants were added, for a total of 51 studies synthesized (N = 21 146 938). From meta-analyses of adjusted effect sizes, moderate-certainty evidence indicated that cannabis use in pregnancy was associated with increased odds of LBW (20 studies; OR, 1.75; 95% CI, 1.41-2.18), PTB (20 studies; OR, 1.52; 95% CI, 1.26-1.83), and SGA (12 studies; OR, 1.57; 95% CI, 1.36-1.81), and low-certainty evidence indicated that it was associated with greater odds of perinatal mortality (6 studies; OR, 1.29; 95% CI, 1.07-1.55). Previously, the evidence was rated as very low or low certainty.

Conclusions and Relevance

Cannabis use in pregnancy was associated with greater odds of PTB, SGA, and LBW even after adjusting for co-use of tobacco products, and confidence in these findings increased from low in the prior review to moderate in the current meta-analysis. The findings of this study may help inform patient counseling and future public health policies.

The impact of cannabinoids on reproductive function

In brief

This review article summarizes the effects of pre- or peri-conceptual exposure to cannabinoids on female and male reproductive function, along with pregnancy outcomes from 2014 to 2024. In particular, it addresses the gaps in knowledge regarding the specific contributions of the major constituents of cannabis, THC and CBD, on reproduction.

Abstract

With increased use of cannabis worldwide, especially in our young adult population, there is a great impetus to understand the impact of cannabis and its constituents (i.e. THC and CBD) on pregnancy, fetal outcomes and male and female reproductive function. This review assessed the current evidence (2014-2024) regarding the effects of cannabinoids on reproductive function (male, female and pregnancy) in animal and human studies. In particular, pre- or periconceptual exposure to cannabinoids were assessed to determine their effects across the lifespan along with transgenerational effects. From the outcomes of this review, we conclude there is a greater need for future preclinical and clinical studies to assess how various routes of cannabinoid exposure along with differing mixtures of cannabinoid constituents may interact to impede reproductive health. Collectively, the outcomes of these studies are important to clinicians and regulatory agencies in the context of functional evidence to support policy and decision-making regarding the safety of cannabis use.

Cannabis or Cannabinoids for the Management of Chronic Noncancer Pain: Best Practice Advice From the American College of Physicians

DESCRIPTION

The American College of Physicians' Population Health and Medical Science Committee (PHMSC) developed this best practice advice to inform clinicians about what is currently known about the benefits and harms of cannabis or cannabinoids in the management of chronic noncancer pain and to provide advice for clinicians counseling patients seeking this therapy.

METHODS

The PHMSC considers areas where evidence is uncertain or emerging or practice does not follow the evidence to provide clinical advice based on a review and assessment of scientific work, including systematic reviews and individual studies. Sources of evidence included a living systematic review on cannabis and cannabinoid treatments for chronic noncancer pain and a series of living systematic reviews and primary studies.

BEST PRACTICE ADVICE 1A

Clinicians should counsel patients about the benefits and harms of cannabis or cannabinoids when patients are considering whether to start or continue to use cannabis or cannabinoids to manage their chronic noncancer pain.

BEST PRACTICE ADVICE 1B

Clinicians should counsel the following subgroups of patients that the harms of cannabis or cannabinoid use for chronic noncancer pain are likely to outweigh the benefits: young adult and adolescent patients, patients with current or past substance use disorder, patients with serious mental illness, and frail patients and those at risk for falling.

BEST PRACTICE ADVICE 2

Clinicians should advise against starting or continuing to use cannabis or cannabinoids to manage chronic noncancer pain in patients who are pregnant or breastfeeding or actively trying to conceive.

BEST PRACTICE ADVICE 3

Clinicians should advise patients against the use of inhaled cannabis to manage chronic noncancer pain.

Cannabis and psychopathology: 2024 Snapshot of a meandering journey

Background

Cannabis has been associated with psychopathology since ancient times, but controversies continue despite important advances in the field. This article is the fourth one in our decadal series of review articles that have been providing an update snapshot of the meandering journey of the research findings in this area.

Aims

This narrative review of a comprehensive literature search over the past 10 years aims to provide an update and current understanding, while raising unanswered questions for the future, focusing on the following areas: (a) nosological changes in cannabis-related psychiatric syndromes; (b) psychopathology associated with the newer category of synthetic cannabinoids; (c) cannabis withdrawal syndrome); (d) cannabis and psychosis; (e) cannabis and mood disorders; (f) cannabis and suicidality; (g) prenatal cannabis use and psychopathology in the offspring; (h) effect of recent liberal policy overhaul on cannabis control in certain countries/areas on psychopathology and adverse outcomes; (i) cannabis and cognition; and (j) cannabis, psychopathology, and genetics.

Methods

The data search strategies involved a combination of electronic databases and manual hand-searching of relevant publications and cross-references using selected search terms. The primary electronic search focused on Medline and PubMed Central databases but extended to databases such as Google Scholar, PsychINFO, Scopus, and Ovid for specific sections. Key references identified through electronic and manual searches provided additional material. Inclusion criteria for the review spanned studies published between January 2014 and June 2024, with more emphasis placed on recent studies (post-2020) while ensuring historical coverage.

Results

The narrative review aimed to be comprehensive, including a broad range of research without strict methodological exclusions. Strengths and limitations of cited research are discussed when applicable, maintaining consistency with three prior reviews. We focused on psychopathology and psychiatric syndromes, human (rather than animal) studies, and applied (rather than basic) research. We have only focused on policy with reference to psychopathology and not on that entire area because that would be beyond the scope of this article. There are important updates in all the areas covered. There are newer syndromal entities in ICD-11, which also includes synthetic cannabinoids for the first time. Cannabis withdrawal syndrome has been better characterized. The association between cannabis and psychosis has been robustly established especially for very high-potency cannabis and for vulnerable populations, particularly young people. Work is in progress elucidating the causal mechanisms. The links between cannabis and mood disorders as well as suicidality and cognitive impairment are better characterized, though questions remain. Recent liberalizing policies on cannabis have produced newer findings on prenatal and accidental cannabis use (with deleterious effects on the offspring) and on later psychopathology (mixed findings, but a documented increase in emergency visits related to recent cannabis use). This is an area which will require active monitoring for new data.

Conclusion

The field of cannabis use and psychopathology continues to collect new data and settle some old controversies while raising new questions, which are important to address in view of the wide use of cannabis worldwide and its implications for public health.

Transgenerational effects of perinatal cannabis exposure on female reproductive parameters in mice

The use of cannabis during pregnancy and nursing is a growing public health concern, and the multigenerational impacts of perinatal cannabis exposure remain largely unknown. To address this knowledge gap, we sought to examine the long-term consequences of perinatal cannabis use on reproductive function and how it might impact subsequent generations. Pregnant female mice were exposed to control vehicle or cannabis extract [25, 100, or 200 mg/ml Δ9-tetrahydrocannabinol (THC) in the cannabis extract] from gestational day 1 to postnatal day 21 (twice/day), encompassing the duration of pregnancy through weaning. Based on plasma THC concentrations in F0 females, we chose 100 and 200 mg/ml THC in the cannabis extract for subsequent studies. The selected doses and exposure conditions did not disrupt pregnancy or nursing in F0 females. Pregnancy and neonatal outcomes, including gestational length, litter size, and sexual ratio, were not affected by cannabis exposure. However, cannabis-exposed neonatal F1 pups were smaller. Cannabis exposure delayed vaginal opening as a sign of puberty onset and disrupted estrous cyclicity in F1 females. However, its effects were minor in F2 and F3 females. F1-F3 females showed no abnormal ovarian and uterine histology or plasma estradiol-17β levels and could produce normal offspring without pregnancy issues. These results suggest that the hypothalamus and pituitary are likely perturbed by perinatal cannabis exposure, and the early hypothalamus-pituitary-ovarian axis is disrupted in F1 females. However, they are not sufficient to compromise adult reproductive function. The present results indicate limited transgenerational effects of perinatal cannabis exposure on female reproductive parameters.

Evaluating maternal drug use disparities, risk factors and outcomes in Northeast Arkansas: a pre, during, and post-COVID-19 pandemic analysis

INTRODUCTION

The use of addictive substances remains a major health problem in the U.S. An increase in drug overdose and mortality was observed during the COVID-19 pandemic, especially in underserved populations. This surge also impacted pregnant women especially with the use of marijuana (THC) and opioids.

METHODS

Retrospective study analyzing mother-infant dyads with reported Meconium Drug Screen (MDS) results, from January 2018 through April 2023 at a reference hospital serving an urban and rural area of Arkansas. Due to the absence of universal screening, the prevalence of drug use was variable during the study period. An adjusted monthly positive rate (AMPR) was calculated by considering the expected number of positive MDS screenings per month and adjusting it based on the screening rate per month and the monthly birth count.

RESULTS

Among 8,030 live births, 957 dyads were included in the analysis, with 47% (N = 450) of infants testing positive for at least one substance. Of these, 64.2%, 11.1%, and 6.7% were positive for THC, amphetamines, and opioids, respectively; and 17.8% tested positive for more than one substance. Infants with a positive MDS (MDS+) had significantly lower weight, height and head circumference with higher preterm rates and longer hospital stays. Mothers who smoked during pregnancy were more than twice as likely to have an MDS + result than those who did not (OR 2.39 (95% CI: 1.34-3.02), and most were from metropolitan areas (73%) or white (67%). The adjusted MDS + rate or AMPR significantly increased over the study period from 6.8% (January 2018) to 7.4% (April 2023). However, the COVID-19 pandemic did not significantly impact these rates. Compared to amphetamines and opioids, THC usage significantly increased during the study period and this increase was more pronounced after the state's legalization of THC.

CONCLUSION

Maternal substance use, predominantly THC, continues to increase, particularly following its legalization. Infants who were MDS + presented adverse neonatal outcomes, with the majority of the mothers being white and from urban settings. Maternal self-reported smoking was associated with increased usage of other substances. Racial disparities were observed during the study, underscoring the need for universal drug testing and targeted interventions.

Systematic review: the impact of maternal pre-and postnatal cannabis use on the behavioral and emotional regulation in early childhood

Prenatal exposure to alcohol and tobacco has been associated with child regulatory abilities and problems, but less is known about the associations with cannabis exposure. This review seeks to address this gap primarily focusing on the effects of maternal cannabis use on the child. Thus, we investigate the association between pre- and postnatal cannabis exposure of the child and regulatory abilities and problems, as well as the underlying neurobiological mechanisms potentially mediating the associations. According to the PRISMA guidelines, a systematic literature review was performed based on a systematic literature search through Medline (PubMed), Web of Science and PsycInfo, including studies assessing children aged 0-6 years with cannabis exposure in the preconception, pre-or postnatal period (preconception, pre- and postnatal cannabis exposure [PCE]) and investigating child regulatory abilities, regulatory problems or neurobiological mechanisms. Of n = 1061 screened articles, n = 33 were finally included. Diminished regulatory abilities are more likely to be found in infants after PCE, while specific regulatory problems tend to be more frequently found after two years of age. Possible mechanisms are related to changes in methylation and expression of key genes involved in endocannabinoid, dopaminergic and opioid systems, increased cortisol reactivity and altered Secretory Immunoglobulin A levels. Furthermore, PCE has been associated with changes in brain structure and connectivity. Current findings indicate that PCE is associated with both age-dependent alterations in self-regulation and neurobiological changes in young children. However, evidence is limited due to the number of studies, small sample sizes and lack of control for maternal psychopathology. Longitudinal studies including psychometric data from mothers are needed in order to further understand the implications of PCE.Trial registration: The review is registered with PROSPERO (ID: CRD42023425115).

Estimating the effects of prenatal cannabis exposure on birth outcomes

BACKGROUND AND OBJECTIVES

Prenatal cannabis use prevalence in the United States has increased. Relaxation of state-level cannabis policy may be contributing to the diminished risk perception of using cannabis. The main psychoactive constituent of cannabis, delta-9-tetrahydrocannabinol, crosses the placenta, interacting with functional cannabinoid receptors in the fetus. Here, we assess the association between prenatal cannabis exposure (PCE) and a set of birth outcomes.

METHODS

Using the Michigan Archive for Research on Child Health, a prospective pregnancy cohort, we linked prenatal survey data with neonatal data from state-archived birth records. Recruitment occurred in 23 clinics across Michigan. Pregnant participants with live birth records between October 2017 and January 2022, after exclusion for missing data on cannabis use, birth outcomes, and covariates, were included in the final analytic sample (n = 584). Analyses involved generalized linear models.

RESULTS

An estimated 15% (95% confidence interval [CI]: 12%, 18%) of participants reported using cannabis during pregnancy. Covariate-adjusted models revealed an association between PCE and birth size (ß = -0.3; 95% CI: -0.5, -0.003).

DISCUSSION AND CONCLUSIONS

Findings suggest a relationship between PCE and smaller birth size. Clinicians should follow guidelines outlined by the American College of Obstetricians and Gynecologists when counseling pregnant patients on cannabis use.

SCIENTIFIC SIGNIFICANCE

We detected a significant association between PCE and birth size. Most studies focus only on the extremes of birth size, however, use of z-scores allow for assessment of the sex-specific birth weight-for-gestational age distribution, increasing the accuracy of detecting an effect of cannabis exposure on birth size.

Prenatal Cannabis Use and Offspring Attention Deficit Hyperactivity Disorder and Disruptive Behavior Disorders: A Retrospective Cohort Study

OBJECTIVE

To examine whether maternal cannabis use during early pregnancy is associated with offspring attention deficit hyperactivity disorder (ADHD) and disruptive behavior disorders (DBD).

METHODS

We conducted a population-based retrospective birth cohort study of children (N = 141,570) born between 2011 and 2018 to pregnant individuals (N = 117,130) in Kaiser Permanente Northern California universally screened for any prenatal cannabis use at the entrance to prenatal care (at ∼8-10 wk gestation). Prenatal cannabis use was defined as (1) self-reported use and/or a positive toxicology test, (2) self-reported use, (3) a positive toxicology test, and (4) self-reported use frequency. Cox proportional hazards regression models adjusting for maternal characteristics (sociodemographics, other substance use and substance use disorders, prenatal care initiation, comorbidities) examined associations between prenatal cannabis use and offspring ADHD and DBD diagnosed by age 11 years.

RESULTS

The sample of pregnant individuals was 27.2% Asian/Pacific Islander, 5.7% Black, 24.5% Hispanic, and 38.8% non-Hispanic White, with a mean (SD) age of 30.9 (5.2) years; 4.6% screened positive for any cannabis use (0.4% daily, 0.5% weekly, 1.1% monthly or less, 2.7% unknown frequency); 3.92% had a positive toxicology test and 1.8% self-reported use; 7.7% of offspring had ADHD and 6.8% had DBD. Maternal prenatal cannabis use was not associated with ADHD (adjusted hazard ratio [aHR]: 0.84, 95% CI, 0.70-1.01), and there was an inverse association with DBD (aHR: 0.83, 95% CI, 0.71-0.97), which remained when cannabis was defined by toxicology testing but not by self-report. Frequency of use was not associated with outcomes.

CONCLUSION

Maternal prenatal cannabis use was not associated with an increased risk of offspring ADHD or DBD.

Risk thresholds for the frequency of cannabis use during pregnancy and adverse neonatal outcomes: protocol for a systematic review and dose-response meta-analysis

BACKGROUND

Cannabis use during pregnancy has been increasing and is associated with adverse neonatal outcomes, such as low birth weight (LBW) and preterm birth (PTB). It remains largely unknown whether the association between cannabis use in pregnancy and increased risk of adverse neonatal outcomes is impacted by the frequency of cannabis use and whether thresholds exist below which risk is not significantly increased. The objective of this systematic review is to assess whether the association between cannabis use during pregnancy and the risk of adverse neonatal outcomes is dependent on the frequency of use and whether risk thresholds exist.

METHODS

For this systematic review and dose-response meta-analysis, the Embase, MEDLINE, PsycINFO, CINAHL, and Web of Science databases will be searched for relevant studies published in English from January 2010 onwards. Studies that include pregnant individuals with singleton pregnancies and evaluate the association between cannabis use in pregnancy and adverse neonatal outcomes using case-control, cohort, or cross-sectional designs will be considered for inclusion. Studies must include information on cannabis use frequency reported according to at least three of the pre-defined categories of no use, yearly (1-11 days per year), monthly (1-3 days per month), weekly (1-4 days per week), and daily/near daily use (5-7 days per week). At least one of the following neonatal outcomes must be reported, according to the frequency of cannabis use: LBW (< 1500 g), PTB (before 37 weeks gestation), neonatal intensive care unit (NICU) admission, and mortality. Studies will be included that report results as risk ratios (RR), odds ratios (OR), hazard ratios (HR), or that include the raw data to be able to calculate them. A two-stage dose-response meta-analysis will be conducted. The risk of bias of included studies will be assessed using the JBI tools for cohort, case-control, and cross-sectional studies. Certainty of the evidence will be reported according to the GRADE approach and the review will be reported according to PRISMA guidelines.

DISCUSSION

The frequency of cannabis is one factor that may influence the relationship between cannabis use in pregnancy and adverse neonatal outcomes. This review will quantify this relationship by determining whether risk thresholds exist.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023479978.

High-Potency Prenatal Cannabis Exposure and Birth Outcome Measures

Background/Objectives: Pregnant women have limited information on the impact of prenatal cannabis exposure (PCE) alone. Our aim was to determine if PCE, without alcohol, tobacco, or illicit drug use, is associated with altered birth outcome measures in obstetrically low-risk women. Methods: In this observational cohort study, pregnant women were recruited between 2019 and 2022 from communities in Washington and Oregon, USA, and enrolled following their first trimester. PCE eligibility required a minimum of three days/week of cannabis use during the first trimester with no required minimum use thereafter. For all participants, illicit drug, nicotine, or alcohol use was exclusionary throughout pregnancy and monitored via urine toxicology at multiple time points. Cannabis use was quantified into delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) mg/day using product weight and potency. Outcome measures included gestational age, weight, length, head circumference, and Apgar scores. Results: Study participants included 37 people in the PCE cohort and 35 controls. Average cannabis use for the PCE cohort was 198.0 mg of THC (SD = 221.2 mg)/day and 3.5 mg of CBD (SD = 4.3)/day. PCE newborns weighed less (38th vs. 52nd percentile, p = 0.04) and were shorter (40th vs. 55th percentile, p = 0.03) for their gestational age than controls. Female PCE newborns had smaller head circumference for gestational age (28th percentile; SD = 23), compared to male PCE newborns (55th percentile; SD = 32; p = 0.02). Conclusions: PCE is associated with reduced birth weight and shorter length for gestational age. The effect of PCE on brain growth may be sexually dimorphic. Future PCE studies should include sex as a biological variable and longitudinally evaluate long-term developmental and physiological outcomes.

Cannabis Use During Early Pregnancy Following Recreational Cannabis Legalization

Importance

It is unknown whether state recreational cannabis legalization (RCL) is related to increased rates of prenatal cannabis use or whether RCL-related changes vary with cannabis screening methods or the local policy environment.

Objective

To test whether RCL in California was associated with changes in prenatal cannabis use rates, whether changes were evident in both self-report and urine toxicology testing, and whether rates varied by local policies banning vs allowing adult-use retailers post-RCL.

Design, Setting, and Participants

This population-based time-series study used data from pregnancies in Kaiser Permanente Northern California universally screened for cannabis use during early pregnancy by self-report and toxicology testing from January 1, 2012, to December 31, 2019. Analyses were conducted from September 2022 to August 2024.

Exposures

California state RCL passage (November 9, 2016) and implementation of legal sales (January 1, 2018) were examined with a 1-month lag. Local policies allowing vs banning medical retailers pre-RCL and adult-use retailers post-RCL were also examined.

Main Outcomes and Measures

Any prenatal cannabis use was based on screening at entrance to prenatal care (typically at 8-10 weeks' gestation) and defined as (1) a positive urine toxicology test result or self-report, (2) a positive urine toxicology test result, or (3) self-report. Interrupted time series models were fit using Poisson regression, adjusting for age, race and ethnicity, and neighborhood deprivation index.

Results

The sample of 300 993 pregnancies (236 327 unique individuals) comprised 25.9% Asian individuals, 6.4% Black individuals, 26.0% Hispanic individuals, 37.7% White individuals, and 4.1% individuals of other, multiple, or unknown race, with a mean (SD) age of 30.3 (5.4) years. Before RCL implementation, rates of prenatal cannabis use rose steadily from 4.5% in January 2012 to 7.1% in January 2018. There was no change in use rates at the time of RCL passage (level change rate ratio [RR], 1.03; 95% CI, 0.96-1.11) and a statistically significant increase in rates in the first month after RCL implementation, increasing to 8.6% in February 2018 (level change RR, 1.10; 95% CI, 1.04-1.16). Results were similar when defining prenatal cannabis use by (1) a toxicology test or (2) self-report. In local policy analyses, the post-RCL implementation increase in use was only found among those in jurisdictions allowing adult-use cannabis retailers (allowed RR, 1.21; 95% CI, 1.10-1.33; banned RR, 1.01; 95% CI, 0.93-1.10).

Conclusions and Relevance

In this time-series study, RCL implementation in California was associated with an increase in rates of cannabis use during early pregnancy, defined by both self-report and toxicology testing, driven by individuals living in jurisdictions that allowed adult-use retailers.

Cannabis and Pregnancy

PURPOSE OF REVIEW

We review recent evidence describing the effects of prenatal exposure to cannabis in pregnant individuals.

RECENT FINDINGS

In the context of changing cannabis policy, more pregnant individuals are using cannabis, despite profound risks. Recent studies show possible perinatal and longitudinal neurodevelopment risks associated with cannabis use during pregnancy and lactation. Healthcare providers are reluctant to discuss this topic with patients for a variety of reasons. With increased access to cannabis comes the possibility of increased adverse effects of cannabis upon pregnant individuals and their children. A concerted effort to educate pregnant individuals about the potential risks of cannabis might mitigate those potential effects.

Maternal Prenatal Cannabis Use and Child Autism Spectrum Disorder

IMPORTANCE

Despite an increase in maternal prenatal cannabis use and associations with adverse neonatal outcomes, research on child neurodevelopmental outcomes is limited.

OBJECTIVE

To evaluate the association between maternal cannabis use in early pregnancy and child autism spectrum disorder (ASD).

DESIGN, SETTING, and PARTICIPANTS

This population-based retrospective birth cohort study included children born between 2011 and 2019 to pregnant Kaiser Permanente Northern California members screened for prenatal cannabis use during pregnancy. Statistical analysis was conducted February 2023 to March 2024.

EXPOSURES

Maternal prenatal cannabis use was assessed at entrance to prenatal care (approximately 8- to 10-weeks' gestation) via self-report and/or positive urine toxicology test. Use frequency was assessed.

Main Outcomes and Measures

Child ASD was defined by International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) diagnosis codes ascertained from the electronic health record. Associations between maternal prenatal cannabis use and child ASD were modeled using Cox proportional hazards regression adjusted for maternal sociodemographic, other substance use and disorders, prenatal care initiation, comorbidities, and clustering among maternal siblings.

RESULTS

The study cohort included 178 948 singleton pregnancies among 146 296 unique pregnant individuals, including 48 880 (27.3%) Asian or Pacific Islander, 42 799 (23.9%) Hispanic, 9742 (5.4%) non-Hispanic Black, and 70 733 (39.5%) non-Hispanic White pregnancies. The median (IQR) maternal age at pregnancy onset was 31 (6) years; 8486 (4.7%) screened positive for cannabis use, 7054 (3.9%) via urine toxicology testing and 3662 (2.0%) by self-report. In the total study population, the frequency of self-reported use was monthly or less for 2003 pregnancies (1.1%), weekly for 918 pregnancies (0.5%), daily for 741 pregnancies (0.4%), and unknown for 4824 pregnancies (2.7%). ASD was diagnosed in 3.6% of children. After adjustment for maternal characteristics, maternal prenatal cannabis use was not associated with child ASD (hazard ratio [HR], 1.05; 95% CI, 0.84-1.32). When self-reported frequency of use was assessed, no statistically significant associations were observed after confounder adjustment. No sex-specific associations were documented (males: HR, 1.01; 95% CI, 0.77-1.32; and females: HR, 1.19; 95% CI, 0.77-1.85).

CONCLUSIONS and Relevance

In this cohort study, maternal cannabis use assessed in early pregnancy was not associated with child ASD. Additional studies are needed to evaluate different patterns of use throughout pregnancy. Given the known adverse neonatal health effects of maternal prenatal cannabis use, clinicians should follow national guidelines and advise against use.

Early Maternal Prenatal Cannabis Use and Child Developmental Delays

Importance

Maternal prenatal cannabis use is associated with adverse neonatal health effects, yet little is known about its association with child developmental outcomes.

Objective

To evaluate associations between maternal prenatal cannabis use in early pregnancy and child early developmental delays.

Design, Setting, and Participants

This cohort study included 119 976 children born to 106 240 unique individuals between January 2015 and December 2019 and followed up to aged 5.5 years or younger (through December 31, 2021) at Kaiser Permanente Northern California. Individuals were screened for prenatal cannabis use via self-report and urine toxicology at entrance into prenatal care (approximately 8- to 10-weeks' gestation). Data were analyzed from February 2023 to March 2024.

Exposure

Maternal prenatal cannabis use defined as any use (self-reported or by urine toxicology testing) and use frequency.

Main Outcomes

Early developmental delays (speech and language disorders, motor delays, global delays) in children up to age 5.5 years defined by International Statistical Classification of Diseases and Related Health Problems, Ninth Revision and Tenth Revision diagnoses codes ascertained from electronic health records.

Results

In this cohort of 119 976 pregnancies among 106 240 unique pregnant individuals, there were 29 543 Hispanic pregnancies (24.6%), 6567 non-Hispanic Black pregnancies (5.5%), 46 823 non-Hispanic White pregnancies (39.0%), 12 837 pregnancies (10.7%) to individuals aged 24 years or younger, and 10 365 pregnancies (8.6%) to individuals insured by Medicaid. Maternal prenatal cannabis use was documented for 6778 pregnancies (5.6%). Daily maternal prenatal cannabis use was reported for 618 pregnancies (0.5%), weekly for 722 pregnancies (0.6%), and monthly or less for 1617 pregnancies (1.3%). No association was observed between maternal prenatal cannabis use and child speech and language disorders (HR, 0.93; 95% CI, 0.84-1.03), global developmental delays (HR, 1.04; 95% CI, 0.68-1.59), or motor delays (HR, 0.86; 95% CI, 0.69-1.06). No association was detected between the frequency of maternal prenatal cannabis use and child early developmental delays.

Conclusions and Relevance

In this cohort study, maternal prenatal cannabis use was not associated with an increased risk of child early developmental delays. Future research is needed to assess different patterns of cannabis use throughout pregnancy. Given the association between maternal prenatal cannabis use and other adverse outcomes, pregnant individuals should be educated on those risks.

Influence of substance use on male reproductive health and offspring outcomes

The prevalence of substance use globally is rising and is highest among men of reproductive age. In Africa, and South and Central America, cannabis use disorder is most prevalent and in Eastern and South-Eastern Europe, Central America, Canada and the USA, opioid use disorder predominates. Substance use might be contributing to the ongoing global decline in male fertility, and emerging evidence has linked paternal substance use with short-term and long-term adverse effects on offspring development and outcomes. This trend is concerning given that substance use is increasing, including during the COVID-19 pandemic. Preclinical studies have shown that male preconception substance use can influence offspring brain development and neurobehaviour through epigenetic mechanisms. Additionally, human studies investigating paternal health behaviours during the prenatal period suggest that paternal tobacco, opioid, cannabis and alcohol use is associated with reduced offspring mental health, in particular hyperactivity and attention-deficit hyperactivity disorder. The potential effects of paternal substance use are areas in which to focus public health efforts and health-care provider counselling of couples or individuals interested in conceiving.

Prenatal Cannabis Use and Maternal Pregnancy Outcomes

Importance

Many studies have evaluated whether in utero cannabis exposure is associated with fetal and neonatal outcomes, yet little is known about whether prenatal cannabis use is associated with maternal health outcomes during pregnancy.

Objective

To evaluate whether prenatal cannabis use is associated with maternal health outcomes during pregnancy.

Design, Setting, and Participants

This population-based retrospective cohort study included pregnancies in Northern California from January 2011 to December 2019 that lasted 20 weeks or longer and were screened for prenatal cannabis use.

Exposures

Prenatal cannabis use was defined as any self-reported use during early pregnancy or a positive toxicology test result based on universal screening at entrance to prenatal care (approximately 8-10 weeks' gestation). Self-reported frequency of use (daily, weekly, monthly or less, never, unknown), use defined only by self-report, and use defined only by toxicology test results were examined.

Main Outcomes and Measures

Electronic health record data were used to define the following outcomes: gestational hypertension, preeclampsia, eclampsia, gestational diabetes, gestational weight gain greater and less than guidelines, placenta previa, placental abruption, placenta accreta, and severe maternal morbidity. Adjusted risk ratios (aRRs) were calculated using a modified Poisson regression.

Results

The sample (n = 316 722 pregnancies; 250 221 unique individuals) included 84 039 (26.5%) Asian/Pacific Islander, 20 053 (6.3%) Black, 83 145 (26.3%) Hispanic, and 118 333 (37.4%) White individuals; the mean (SD) age was 30.6 (5.4) years. Overall, 20 053 (6.3%) screened positive for prenatal cannabis use; 2.9% were positive by self-report, 5.3% by toxicology testing, and 1.8% by both. The frequency of cannabis use was 1930 (0.6%) daily, 2345 (0.7%) weekly, 4892 (1.5%) monthly or less, and 10 886 (3.4%) unknown. Prenatal cannabis use was associated with greater risk of gestational hypertension (aRR, 1.17; 95% CI, 1.13-1.21), preeclampsia (aRR, 1.08; 95% CI, 1.01-1.15), weight gain less than (aRR, 1.05; 95% CI, 1.01-1.08) and greater than (aRR, 1.09; 95% CI, 1.08-1.10) guidelines, and placental abruption (aRR, 1.19; 95% CI, 1.05-1.36). The pattern of results was similar when defining prenatal cannabis use only by self-report or only by toxicology testing, and associations between the frequency of prenatal cannabis use and outcomes varied with outcome.

Conclusions and Relevance

The results of this cohort study suggest that prenatal cannabis use was associated with several adverse maternal health outcomes during pregnancy. Continued research is needed to understand whether characteristics of prenatal cannabis use (eg, dose, mode, and timing) moderate these associations.

The longitudinal assessment of prenatal cannabis use on neonatal outcomes

OBJECTIVE

To investigate the association between prenatal cannabis use and perinatal outcomes using longitudinal data from pregnant individuals.

STUDY DESIGN

This secondary-data analysis study utilized data collected from 894 pregnant individuals followed in the Stress in Pregnancy longitudinal study, conducted between 2009 and 2013. The status of cannabis use was ascertained through interviews and electronic medical record reviews to evaluate the effect of cannabis use on perinatal outcomes (NICU admission, preterm delivery, low birth weight, fetal death).

RESULTS

Among participants analyzed, 13.1% used cannabis, who were generally younger (25.9 vs 27.9 years). There was a sevenfold increased risk of fetal death (OR 7.30) among cannabis users relative to non-users. Elevated risk persisted after adjustments of potential confounders (aOR 6.31). Adjusted models also suggested increased low birth weight risk (aOR 1.67).

CONCLUSION

This study highlights an association between prenatal cannabis use and elevated risks for fetal death and low birth weight.

Neonatal outcomes associated with in utero cannabis exposure: a population-based retrospective cohort study

BACKGROUND

The full spectrum of associations between in utero cannabis exposure and adverse neonatal outcomes is still unclear.

OBJECTIVE

This study aimed to evaluate the associations between in utero cannabis exposure and neonatal outcomes.

STUDY DESIGN

This population-based retrospective cohort study of singleton births among Kaiser Permanente Northern California members (January 1, 2011-July 31, 2020) included parent-infant dyads in which the pregnant parent was screened for cannabis use as part of standard prenatal care, generally upon entrance into care. Data were ascertained from electronic health records. Generalized estimating equation models were adjusted for sociodemographic characteristics, other non-cannabis prenatal substance use, medical and mental health comorbidities, and adequacy of prenatal care. In utero cannabis exposure was defined as self-reported use since becoming pregnant and/or a positive urine toxicology test for cannabis at any time during pregnancy (yes/no; primary exposure). Frequency of use was self-reported and categorized as daily, weekly, monthly or less, never, or unknown (secondary exposure). Neonatal outcomes included low birthweight, small for gestational age, preterm birth, neonatal intensive care unit admission, and infant respiratory support.

RESULTS

Of 364,924 infants, 22,624 (6.2%) were exposed to cannabis in utero. After adjustment for potential confounders, including in utero exposure to other substances, in utero exposure to cannabis was associated with greater odds of low birthweight (adjusted odds ratio, 1.20; 95% confidence interval, 1.12-1.28), small for gestational age (adjusted odds ratio, 1.24; 95% confidence interval, 1.18-1.30), preterm birth (<37 weeks; adjusted odds ratio, 1.06; 95% confidence interval, 1.00-1.13), and neonatal intensive care unit admission (adjusted odds ratio, 1.06; 95% confidence interval, 1.01-1.11). There was a suggestive association with early preterm birth (<34 weeks; adjusted odds ratio, 1.11; 95% confidence interval, 1.00-1.23; P=.055), but no significant association with respiratory support (adjusted odds ratio, 1.07; 95% confidence interval, 0.97-1.18). Dose-response analysis found an increasing likelihood of low birthweight and small for gestational age with increasing frequency of prenatal cannabis use by the pregnant individual. Sensitivity analyses further supported an increased likelihood of low birthweight and small for gestational age, although associations with other outcomes did not reach statistical significance.

CONCLUSION

In utero cannabis exposure was associated with increased likelihood of low birthweight, small for gestational age, preterm birth, and neonatal intensive care unit admission. Clinicians should counsel individuals who are pregnant or considering pregnancy about the potential adverse neonatal health outcomes associated with prenatal cannabis use.

Human Milk Cannabinoid Concentrations and Associations with Maternal Factors: The Lactation and Cannabis (LAC) Study

Background and Objectives: As cannabis use increases among reproductive-aged women, there is a growing need to better understand the presence of cannabinoids in milk produced by women using cannabis. It is unclear how concentrations of cannabinoids such as delta-9-tetrahydrocannabinol (Δ9-THC) persist in milk after cannabis use and what factors contribute to variation in milk Δ9-THC concentrations. Our objectives were to measure cannabinoids in human milk following cannabis abstention, after single and repeated instances of cannabis use, and identify factors contributing to concentration variation. Methods: The Lactation and Cannabis (LAC) Study prospectively observed 20 breastfeeding participants who frequently used cannabis (≥1/week), had enrolled <6 months postpartum, were feeding their infant their milk ≥5 times/day, and were not using any illicit drugs. Participants collected a baseline milk sample after ≥12 hours of abstaining from cannabis and five milk samples at set intervals over 8-12 hours after initial cannabis use. Participants completed surveys and recorded self-directed cannabis use during the study period. Results: Δ9-THC peaked 120 minutes after a single instance of cannabis use (median, n = 9). More instances of cannabis use during the study period were associated with greater Δ9-THC area-under-the-curve concentrations (ρ = 0.65, p = 0.002), indicating Δ9-THC bioaccumulation in most participants. Baseline Δ9-THC logged concentration was positively associated with self-reported frequency of cannabis use (b = 0.57, p = 0.01). Conclusions: Cannabinoids are measurable in human milk following cannabis use, and concentrations remain elevated with repeated cannabis use over a day. Substantial variation in Δ9-THC milk concentrations reflects individual differences in characteristics and behavior, including average postpartum frequency of cannabis use.

Cannabis Science and Therapeutics: An Overview for Clinicians

Cannabis-based therapeutics have garnered increasing attention in recent years as patients seek alternative treatments for various medical conditions. This narrative review provides a comprehensive overview of the science behind the medical use of cannabis, focusing on the medical evidence for commonly treated conditions. In addition, the review addresses the practical considerations of using cannabis as a therapeutic agent, offering insights into dosing strategies, variations in cannabinoid formulation, and individual patient responses. Precautions, adverse consequences, and drug interactions are also discussed, with a focus on patient safety and the potential risks associated with cannabis use.

Risk of Adverse Neonatal Outcomes After Combined Prenatal Cannabis and Nicotine Exposure

Importance

The prevalence of cannabis use in pregnancy is rising and is associated with adverse perinatal outcomes. In parallel, combined prenatal use of cannabis and nicotine is also increasing, but little is known about the combined impact of both substances on pregnancy and offspring outcomes compared with each substance alone.

Objective

To assess the perinatal outcomes associated with combined cannabis and nicotine exposure compared with each substance alone during pregnancy.

Design, Setting, and Participants

This retrospective population-based cohort study included linked hospital discharge data (obtained from the California Department of Health Care Access and Information) and vital statistics (obtained from the California Department of Public Health) from January 1, 2012, through December 31, 2019. Pregnant individuals with singleton gestations and gestational ages of 23 to 42 weeks were included. Data were analyzed from October 14, 2023, to March 4, 2024.

Exposures

Cannabis-related diagnosis and prenatal nicotine product use were captured using codes from International Classification of Diseases, Ninth Revision, Clinical Modification, and International Statistical Classification of Diseases, Tenth Revision, Clinical Modification.

Main Outcome and Measures

The main outcomes were infant and neonatal death, infants small for gestational age, and preterm delivery. Results were analyzed by multivariable Poisson regression models.

Results

A total of 3 129 259 pregnant individuals were included (mean [SD] maternal age 29.3 [6.0] years), of whom 23 007 (0.7%) had a cannabis-related diagnosis, 56 811 (1.8%) had a nicotine-use diagnosis, and 10 312 (0.3%) had both in pregnancy. Compared with nonusers, those with cannabis or nicotine use diagnoses alone had increased rates of infant (0.7% for both) and neonatal (0.3% for both) death, small for gestational age (14.3% and 13.7%, respectively), and preterm delivery (<37 weeks) (12.2% and 12.0%, respectively). Moreover, risks in those with both cannabis and nicotine use were higher for infant death (1.2%; adjusted risk ratio [ARR], 2.18 [95% CI, 1.82-2.62]), neonatal death (0.6%; ARR, 1.76 [95% CI, 1.36-2.28]), small for gestational age (18.0%; ARR, 1.94 [95% CI, 1.86-2.02]), and preterm delivery (17.5%; ARR, 1.83 [95% CI, 1.75-1.91]).

Conclusions and Relevance

These findings suggest that co-occurring maternal use of cannabis and nicotine products in pregnancy is associated with an increased risk of infant and neonatal death and maternal and neonatal morbidity compared with use of either substance alone. Given the increasing prevalence of combined cannabis and nicotine use in pregnancy, these findings can help guide health care practitioners with preconception and prenatal counseling, especially regarding the benefits of cessation.

Prenatal delta-9-tetrahydrocannabinol exposure alters fetal neurodevelopment in rhesus macaques

Prenatal cannabis use is associated with adverse offspring neurodevelopmental outcomes, however the underlying mechanisms are relatively unknown. We sought to determine the impact of chronic delta-9-tetrahydrocannabinol (THC) exposure on fetal neurodevelopment in a rhesus macaque model using advanced imaging combined with molecular and tissue studies. Animals were divided into two groups, control (n = 5) and THC-exposed (n = 5), which received a daily THC edible pre-conception and throughout pregnancy. Fetal T2-weighted MRI was performed at gestational days 85 (G85), G110, G135 and G155 to assess volumetric brain development. At G155, animals underwent cesarean delivery with collection of fetal cerebrospinal fluid (CSF) for microRNA (miRNA) studies and fetal tissue for histologic analysis. THC exposure was associated with significant age by sex interactions in brain growth, and differences in fetal brain histology suggestive of brain dysregulation. Two extracellular vesicle associated-miRNAs were identified in THC-exposed fetal CSF; pathway analysis suggests that these miRNAs are associated with dysregulated axonal guidance and netrin signaling. This data is indicative of subtle molecular changes consistent with the observed histological data, suggesting a potential role for fetal miRNA regulation by THC. Further studies are needed to determine whether these adverse findings correlate with long-term offspring neurodevelopmental health.

Prenatal delta-9-tetrahydrocannabinol exposure is associated with changes in rhesus macaque DNA methylation enriched for autism genes

BACKGROUND

With the growing availability of cannabis and the popularization of additional routes of cannabis use beyond smoking, including edibles, the prevalence of cannabis use in pregnancy is rapidly increasing. However, the potential effects of prenatal cannabis use on fetal developmental programming remain unknown.

RESULTS

We designed this study to determine whether the use of edible cannabis during pregnancy is deleterious to the fetal and placental epigenome. Pregnant rhesus macaques consumed a daily edible containing either delta-9-tetrahydrocannabinol (THC) (2.5 mg/7 kg/day) or placebo. DNA methylation was measured in 5 tissues collected at cesarean delivery (placenta, lung, cerebellum, prefrontal cortex, and right ventricle of the heart) using the Illumina MethylationEPIC platform and filtering for probes previously validated in rhesus macaque. In utero exposure to THC was associated with differential methylation at 581 CpGs, with 573 (98%) identified in placenta. Loci differentially methylated with THC were enriched for candidate autism spectrum disorder (ASD) genes from the Simons Foundation Autism Research Initiative (SFARI) database in all tissues. The placenta demonstrated greatest SFARI gene enrichment, including genes differentially methylated in placentas from a prospective ASD study.

CONCLUSIONS

Overall, our findings reveal that prenatal THC exposure alters placental and fetal DNA methylation at genes involved in neurobehavioral development that may influence longer-term offspring outcomes. The data from this study add to the limited existing literature to help guide patient counseling and public health polices focused on prenatal cannabis use in the future.