Maternal marijuana use has independent effects on risk for spontaneous preterm birth but not other common late pregnancy complications

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

Objective: To determine whether prenatal cannabis use alone increases the likelihood of fetal and neonatal morbidity and mortality. Study Design: We searched bibliographic databases, such as PubMed, Embase, Scopus, Cochrane reviews, PsycInfo, MEDLINE, Clinicaltrials.gov, and Google Scholar from inception through February 14, 2022. Cohort or case-control studies with prespecified fetal or neonatal outcomes in pregnancies with prenatal cannabis use. Primary outcomes were preterm birth (PTB; <37 weeks of gestation), small-for-gestational-age (SGA), birthweight (grams), and perinatal mortality. Two independent reviewers screened studies. Studies were extracted by one reviewer and confirmed by a second using a predefined template. Risk of bias assessment of studies, using the Newcastle-Ottawa Quality Assessment Scale, and Grading of Recommendations Assessment, Development, and Evaluation for evaluating the certainty of evidence for select outcomes were performed by two independent reviewers with disagreements resolved by a third. Random effects meta-analyses were conducted, using adjusted and unadjusted effect estimates, to compare groups according to prenatal exposure to cannabis use status. Results: Fifty-three studies were included. Except for birthweight, unadjusted and adjusted meta-analyses had similar results. We found very-low- to low-certainty evidence that cannabis use during pregnancy was significantly associated with greater odds of PTB (adjusted odds ratio [aOR], 1.42; 95% confidence interval [CI], 1.19 to 1.69; I2, 93%; p=0.0001), SGA (aOR, 1.76; 95% CI, 1.52 to 2.05; I2, 86%; p<0.0001), and perinatal mortality (aOR, 1.5; 95% CI, 1.39 to 1.62; I2, 0%; p<0.0001), but not significantly different for birthweight (mean difference, -40.69 g; 95% CI, -124.22 to 42.83; I2, 85%; p=0.29). Because of substantial heterogeneity, we also conducted a narrative synthesis and found comparable results to meta-analyses. Conclusion: Prenatal cannabis use was associated with greater odds of PTB, SGA, and perinatal mortality even after accounting for prenatal tobacco use. However, our confidence in these findings is limited. Limitations of most existing studies was the failure to not include timing or quantity of cannabis use. This review can help guide health care providers with counseling, management, and addressing the limited existing safety data. Protocol Registration: PROSPERO CRD42020172343.

Prenatal Exposure to Cannabis: Effects on Childhood Obesity and Cardiometabolic Health

PURPOSE OF REVIEW

To consolidate information on the obesogenic and cardiometabolic effects of prenatal exposure to cannabis.

RECENT FINDINGS

A PubMed search strategy updated from January 1, 2014, through 14 June 2023, produced a total of 47 epidemiologic studies and 12 animal studies. Prenatal exposure to cannabis is consistently associated with small for gestational age and low birth weight. After birth, these offspring gain weight rapidly and have increased adiposity and higher glucose (fat mass percentage) in childhood. More preclinical and prospective studies are needed to deepen our understanding of whether these associations vary by sex, dose, timing, and composition of cannabis (e.g., ratio of delta-Δ9-tetrahydrocannabinol [Δ9-THC] to cannabidiol [CBD]). Addressing these gaps may help to solidify causality and identify intervention strategies. Based on the available data, clinicians and public health officials should continue to caution against cannabis use during pregnancy to limit its potential obesogenic and adverse cardiometabolic effects on the offspring.

The Effects of Cannabis Use during Pregnancy on Low Birth Weight and Preterm Birth: A Systematic Review and Meta-analysis

OBJECTIVE

Our objective was to summarize the literature regarding the effects of cannabis use during pregnancy on low birth weight (LBW), preterm birth (PTB), and small for gestational age (SGA).

STUDY DESIGN

This is a systematic review and meta-analysis. A literature search was conducted in PubMed, Scopus, EBSCO, and Web of Science in May 2021 and updated in November 2021. Only studies that assessed the isolated use of cannabis during pregnancy, controlling for cigarette smoking, and other illicit drug use were included. Data were synthesized using a narrative summary and pooled adjusted estimates, and 95% confidence intervals (CIs) were calculated for each outcome. Data were analyzed using Stata 13.0 with METAN software package, using random effects. Statistical heterogeneity was assessed using Cochran's Q and Higgins I2 tests.

RESULTS

In total, 32 studies were included with data from approximately 5.5 million women with the LBW outcome and 23 million with the PTB and SGA outcomes. Pregnant women using cannabis are at increased risk for LBW (adjusted odds ratio [aOR] = 1.52; 95% CI = [1.18; 1.96]), PTB (aOR = 1.39; 95% CI = [1.28; 1.51]), and SGA (aOR = 1.47; 95% CI = [1.38; 1.58]). Studies that assessed the type of PTB and gestational age at birth indicate higher risks of spontaneous PTB and of early or very-early PTBs associated with cannabis use during pregnancy. The few studies that assessed the timing and frequency of consumption suggest a dose-response effect, with higher odds of negative outcomes among women who reported heavy use and with continued use during the second and third trimesters of gestation.

CONCLUSION

There is an effect of cannabis irrespective of other illicit drugs and tobacco despite high heterogeneity and low quality of evidence. There is a need to discuss public policies regarding cannabis' regulation and how it influences its consumption. Future studies should focus on the effects of cannabis's type (medicinal or recreational), timing, and dosage during pregnancy on perinatal outcomes.

KEY POINTS

· Cannabis use during pregnancy is increasing.. · Cannabis has an independent effect on PTB, LBW, and SGA.. · Future studies should focus on the timing of exposure during pregnancy, mode of use, and dosage..

The association between preconception cannabis use and gestational diabetes mellitus: The Preconception Period Analysis of Risks and Exposures Influencing health and Development (PrePARED) consortium

BACKGROUND

The metabolic changes that ultimately lead to gestational diabetes mellitus (GDM) likely begin before pregnancy. Cannabis use might increase the risk of GDM by increasing appetite or promoting fat deposition and adipogenesis.

OBJECTIVES

We aimed to assess the association between preconception cannabis use and GDM incidence.

METHODS

We analysed individual-level data from eight prospective cohort studies. We identified the first, or index, pregnancy (lasting ≥20 weeks of gestation with GDM status) after cannabis use. In analyses of pooled individual-level data, we used logistic regression to estimate study-type-specific odds ratios (OR) and 95% confidence intervals (CI), adjusting for potential confounders using random effect meta-analysis to combine study-type-specific ORs and 95% CIs. Stratified analyses assessed potential effect modification by preconception tobacco use and pre-pregnancy body mass index (BMI).

RESULTS

Of 17,880 participants with an index pregnancy, 1198 (6.7%) were diagnosed with GDM. Before the index pregnancy, 12.5% of participants used cannabis in the past year. Overall, there was no association between preconception cannabis use in the past year and GDM (OR 0.97, 95% CI 0.79, 1.18). Among participants who never used tobacco, however, those who used cannabis more than weekly had a higher risk of developing GDM than those who did not use cannabis in the past year (OR 2.65, 95% CI 1.15, 6.09). This association was not present among former or current tobacco users. Results were similar across all preconception BMI groups.

CONCLUSIONS

In this pooled analysis of preconception cohort studies, preconception cannabis use was associated with a higher risk of developing GDM among individuals who never used tobacco but not among individuals who formerly or currently used tobacco. Future studies with more detailed measurements are needed to investigate the influence of preconception cannabis use on pregnancy complications.

The Role of Hemp (Cannabis sativa L.) as a Functional Food in Vegetarian Nutrition

Recently, there has been a renewed interest in Cannabis sativa and its uses. The recreational use of inflorescences as a source of THC has led to the legal restriction of C. sativa cultivation to limit the detrimental effects of psychotropic substance abuse on health. However, this has also limited the cultivation of textile/industrial varieties with a low content of THC used for textile and nutritional purposes. While previously the bans had significantly penalized the cultivation of C. sativa, today many countries discriminate between recreational use (marijuana) and industrial and food use (hemp). The stalks of industrial hemp (low in psychotropic substances) have been used extensively for textile purposes while the seeds are nutritionally versatile. From hemp seeds, it is possible to obtain flours applicable in the bakery sector, oils rich in essential fatty acids, proteins with a high biological value and derivatives for fortification, supplementation and nutraceutical purposes. Hemp seed properties seem relevant for vegetarian diets, due to their high nutritional value and underestimated employment in the food sector. Hemp seed and their derivatives are a valuable source of protein, essential fatty acids and minerals that could provide additional benefit to vegetarian nutrition. This document aims to explore the information available in the literature about hemp seeds from a nutritional point of view, highlighting possible beneficial effects for humans with particular attention to vegetarian nutrition as a supplemental option for a well-planned diet.

Cannabis use during pregnancy and its effect on the fetus, newborn and later childhood: A systematic review

INTRODUCTION

Cannabis and its derivatives are becoming increasingly popular in women's preferences during pregnancy in order to relieve nausea. The present study examines cannabis use during pregnancy and its effects on the fetus, newborn and later childhood.

METHODS

All primary studies were searched in the databases: PubMed, Scopus, Medline during the period June 2019 to August 2020. The keywords used were 'pregnancy', 'pregnant women', 'cannabis', 'marijuana', 'fetus', 'newborn', 'childhood', and combined with 'AND' and 'OR' Boolean operators. Inclusion criteria were: pregnant users of cannabis as the study group and pregnant non-users of cannabis as the control group; the articles could be in English or in Greek. The exclusion criteria were: unpublished studies, reviews, presentations at conferences, and animal studies.

RESULTS

From the systematic review of the literature, the study included 13 primary research studies in which it was found that the children of mother-user faced: disorders in the sleep cycle, memory problems, hyperactivity, increased chances of low birth weight, prematurity with lower Apgar score in the 1st and 5th minutes and hospitalization in an NICU, DNA methylation at the position CpG.32, and modifications in the brain, especially in the amygdala. In addition, girls had more aggressive behavior at the age of 18 months, shorter breastfeeding period, and neonatal death.

CONCLUSIONS

The use of cannabis during the gestation period by the mother, aggravates the physical and mental development of the fetus, the newborn and the later childhood.

The effect of prenatal cannabis exposure on offspring preterm birth: a cumulative meta-analysis

BACKGROUND AND AIMS

Mixed results have been reported on the association between prenatal cannabis exposure and preterm birth. This study aimed to examine the magnitude and consistency of associations reported between prenatal cannabis exposure and preterm birth.

METHODS

This review was guided by the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. We performed a comprehensive search of the literature on the following electronic databases: PubMed, EMBASE, SCOPUS, Psych-INFO and Web of Science. The revised version of the Newcastle-Ottawa Scale (NOS) was used to appraise the methodological quality of the studies included in this review. Inverse variance weighted random-effects cumulative meta-analysis was undertaken to pool adjusted odds ratios (aOR) after sequential inclusion of each newly published study over time. The OR and 95% confidence interval (CI) limits required (stability threshold) for a new study to move the cumulative odds ratio to the null were also computed.

RESULTS

A total of 27 observational studies published between 1986 and 2022 were included in the final cumulative meta-analysis. The sample size of the studies ranged from 304 to 4.83 million births. Prenatal cannabis exposure was associated with an increased risk of preterm birth (pooled aOR = 1.35, 95% CI = 1.24-1.48). The stability threshold was 0.74 (95% CI limit = 0.81) by the end of 2022.

CONCLUSIONS

Offspring exposed to maternal prenatal cannabis use was associated with higher risk of preterm birth, which warrants public health messages to avoid such exposure, particularly during pregnancy.

Association between Prenatal Marijuana and Tobacco Smoke Exposures and Small for Gestational Age at Birth

OBJECTIVE

The aim of this study was to determine the association of prenatal marijuana exposure with and without tobacco smoke exposure and small for gestational age (SGA) at birth.

STUDY DESIGN

We conducted a secondary analysis of the prospective Lifestyle and Early Achievement in Families (LEAF) cohort enrolled from 2010 to 2015. We included singleton nonanomalous liveborn pregnancies. We assessed marijuana use inclusive of any pregnancy urine specimen with a Δ9-THC-COOH concentration of more than 15 ng/mL by mass spectrometry, self-report on questionnaire, and/or electronic health record; and self-reported maternal tobacco use. Because of the high co-frequency of marijuana with tobacco exposure in pregnancy and the known association between tobacco and fetal growth restriction, we modeled the exposure as: both marijuana and tobacco (hereafter "co-use"), only marijuana, only tobacco, and neither (reference). Incidence of SGA in each group was compared with the neither group. The primary outcome was SGA less than 10th percentile, and secondarily less than 5th percentile, using parity-specific definitions per 2017 US natality reference data.

RESULTS

Among 325 assessed mothers, 46% had neither exposure, 11% had only prenatal marijuana exposure, 20% only tobacco exposure, and 23% co-use exposure. A third (33%) of infants were SGA less than 10th percentile and 20% SGA less than 5th percentile. Marijuana exposure only was associated with an increased risk of SGA less than 10th percentile (43 vs. 26%; adjusted relative risk [aRR]: 1.66; 95% confidence interval [CI]: 1.02-2.69), and SGA less than5th percentile (30 vs. 13%; aRR: 2.26; 95% CI: 1.15-4.47). Tobacco was not associated with SGA less than 10th percentile, but was with SGA less than 5th percentile (26 vs. 13%; aRR: 2.01; 95% CI: 1.13, 3.56). Co-use was not associated with increased SGA risk in multivariate analysis, but was in sensitivity analysis when tobacco use was defined using a cotinine assay rather than self-report (SGA <10th percentile, aRR: 1.97; 95% CI: 1.24-3.15) and (SGA <5th percentile, aRR: 2.03; 95% CI: 1.09-3.78).

CONCLUSION

Prenatal marijuana exposure in addition to tobacco may increase the risk of SGA. Given the rising prevalence of marijuana use in pregnancy, further research is warranted to understand how in utero marijuana exposure may impact fetal growth and birth weight with and without tobacco exposure.

KEY POINTS

· Marijuana and tobacco are commonly used together in pregnancy.. · Prenatal marijuana and tobacco exposure may increase the risk of a small for gestational age infant.. · Further research is warranted to understand how in utero marijuana exposure impacts fetal growth..

Prevalence and Patterns of Prenatal Alcohol Exposure in Australian Cohort and Cross-Sectional Studies: A Systematic Review of Data Collection Approaches

This study sought to determine data collection approaches in Australian cohort studies and explore the potential impact on reported prenatal alcohol exposure (PAE) prevalence and patterns. Inclusion criteria were that studies related to a general Australian antenatal population where PAE was assessed and reported. Studies were excluded if they were not peer reviewed, examined the prevalence of PAE in pregnancies complicated by alcohol-use disorders, or were published in a language other than English. A systematic search of five electronic databases (PubMed, Embase, CINAHL, Web of Science, and Scopus) was conducted. Risk of bias was assessed using the Effective Public Health Practice Project quality assessment tool. Results were synthesised using MetaXL. Data from 16 separate birth cohorts (n = 78 articles) were included. Included cohorts were either general cohorts that included alcohol as a variable or alcohol-focused cohorts that were designed with a primary focus on PAE. PAE prevalence was estimated as 48% (95% CI: 38 to 57%). When subgroup analysis was performed, estimates of PAE prevalence when self-administered surveys and interviews were used for data collection were 53% (95% CI: 41% to 64%) and 43% (95% CI: 28% to 59%), respectively. Use of trained assessors was an influencing factor of the prevalence estimates when data were collected via interview. Alcohol-focused studies reported higher prevalence of PAE, regardless of method of survey administration. Where interviewer training is not possible, self-administered questionnaires will likely provide the most reliable PAE estimates. No funding sources are relevant to mention. Review was registered with PROSPERO (CRD42020204853).

Alcohol Intake and Hypertensive Disorders of Pregnancy: A Negative Control Analysis in the ALSPAC Cohort

Background Alcohol intake increases blood pressure yet estimates of associations between maternal intake and hypertensive disorders of pregnancy (HDP) are sparse and range from null to a protective effect. Here we estimated the association of maternal drinking during pregnancy with preeclampsia and gestational hypertension (separately and jointly, as HDP). We used partner's alcohol intake as a negative control exposure, beverage type-specific models, and a range of sensitivity analyses to strengthen causal inference and reduce the influence of bias. Methods and Results We performed a longitudinal analysis of prospectively collected data on self-reported alcohol intake and presence of HDP from the UK ALSPAC (Avon Longitudinal Study of Parents and Children) cohort. Multivariable multinomial regression models were adjusted for confounders and mutually adjusted for partner's or maternal alcohol intake in the negative control analysis. We also performed a beverage type analysis of the effect of beer and wine separately on HDP risk, owing to different social patterning associated with different drinks. Sensitivity analyses assessed the robustness of results to assumptions of no recall bias, no residual confounding, and no selection bias. Of the 8999 women eligible for inclusion, 1490 fulfilled the criteria for HDP (17%). Both maternal and partner's drinking were associated with decreased HDP odds (mutually adjusted odds ratio [OR], 0.86; [95% CI, 0.77-0.96], P=0.008 and OR, 0.82; [95% CI, 0.70-0.97], P=0.018, respectively). We demonstrate the validity of the negative control analyses using the same approach for smoking as the exposure. This confirmed an inverse association for maternal but not partner's smoking, as expected. Estimates were more extreme for increasing levels of wine intake compared with increasing levels of beer. Multiple sensitivity analyses did not alter our conclusions. Conclusions We observed an inverse relationship between alcohol intake during pregnancy and risk of HDP for both maternal and, more surprisingly, partner's drinking. We speculate that this is more likely to be due to common environmental exposures shared between pregnant women and their partners rather than a true causal effect. This warrants further investigation using different study designs, including Mendelian randomization.

Prenatal marijuana exposure and neonatal outcomes: a retrospective cohort study

OBJECTIVES

Previous literature on the effects of marijuana exposure on neonatal outcomes has been limited by the reliance on maternal self-report. The objective of this study was to examine the relationship of prenatal marijuana exposure on neonatal outcomes in infants with marijuana exposure confirmed with meconium drug testing.

DESIGN

Retrospective cohort study.

SETTING AND PARTICIPANTS

Meconium drug screens obtained on infants born in a hospital system in the Pacific Northwest in the USA over a 2.5-year period. 1804 meconium drug screens were initially obtained, with 1540 drug screens included in the analysis.

PRIMARY AND SECONDARY OUTCOME MEASURES

Neonates with meconium drug screens positive for delta-9-tetrahydrocannabinol (THC) only were compared with neonates with negative drug screens. The following neonatal outcomes were examined: gestational age, preterm birth (<37 weeks), birth weight, low birth weight (defined as birth weight <2.5 kg), length, head circumference, Apgar scores and admission to the neonatal intensive care unit (NICU). Using multivariable logistical and linear regression, we controlled for confounding variables.

RESULTS

1540 meconium drug screens were included in the analysis, with 483 positive for delta-9-THC only. Neonates exposed to delta-9-THC had significantly lower birth weight, head circumference and length (p<0.001). Neonates with THC exposure had 1.9 times the odds (95% CI 1.3 to 2.7, p=0.001) of being defined as low birth weight. Birth weight was on average 0.16 kg lower (95% CI 0.10 to 0.22, p<0.001) in those exposed to THC.

CONCLUSIONS

Prenatal marijuana exposure was significantly associated with decreases in birth weight, length and head circumference, and an increased risk of being defined as low birth weight. These findings add to the previous literature demonstrating possible negative effects of prenatal marijuana use on neonatal outcomes.

Neurogenetic and Epigenetic Aspects of Cannabinoids

Cannabis is one of the most commonly used and abused illicit drugs in the world today. The United States (US) currently has the highest annual prevalence rate of cannabis consumption in the world, 17.9% in individuals aged 12 or older, and it is on the rise. With increasing cannabis use comes the potential for an increase in abuse, and according to the Substance Abuse and Mental Health Services Administration (SAMHSA), approximately 5.1% of Americans had Cannabis Use Disorder (CUD) in 2020. Research has shown that genetics and epigenetics play a significant role in cannabis use and CUD. In fact, approximately 50–70% of liability to CUD and 40–48% of cannabis use initiation have been found to be the result of genetic factors. Cannabis usage and CUD have also been linked to an increased risk of psychiatric disorders and Reward Deficiency Syndrome (RDS) subsets like schizophrenia, depression, anxiety, and substance use disorder. Comprehension of the genetic and epigenetic aspects of cannabinoids is necessary for future research, treatment plans, and the production of pure cannabinoid compounds, which will be essential for FDA approval. In conclusion, having a better understanding of the epigenetic and genetic underpinnings of cannabis use, CUD, and the endocannabinoid system as a whole will aid in the development of effective FDA-approved treatment therapies and the advancement of personalized medicine.

Prenatal Exposure to Delta-9-tetrahydrocannabinol (THC) Alters the Expression of miR-122-5p and Its Target Igf1r in the Adult Rat Ovary

As cannabis use during pregnancy increases, it is important to understand its effects on the developing fetus. Particularly, the long-term effects of its psychoactive component, delta-9-tetrahydrocannabinol (THC), on the offspring’s reproductive health are not fully understood. This study examined the impact of gestational THC exposure on the miRNA profile in adult rat ovaries and the possible consequences on ovarian health. Prenatal THC exposure resulted in the differential expression of 12 out of 420 evaluated miRNAs. From the differentially expressed miRNAs, miR-122-5p, which is highly conserved among species, was the only upregulated target and had the greatest fold change. The upregulation of miR-122-5p and the downregulation of its target insulin-like growth factor 1 receptor (Igf1r) were confirmed by RT-qPCR. Prenatally THC-exposed ovaries had decreased IGF-1R-positive follicular cells and increased follicular apoptosis. Furthermore, THC decreased Igf1r expression in ovarian explants and granulosa cells after 48 h. As decreased IGF-1R has been associated with diminished ovarian health and fertility, we propose that these THC-induced changes may partially explain the altered ovarian follicle dynamics observed in THC-exposed offspring. Taken together, our data suggests that prenatal THC exposure may impact key pathways in the developing ovary, which could lead to subfertility or premature reproductive senescence.

Directive clinique no 425b : Le cannabis aux différentes périodes de la vie des femmes - Partie 2 : Grossesse, période postnatale et allaitement

OBJECTIF

Fournir aux fournisseurs de soins les meilleures données probantes sur l'utilisation de cannabis et la santé des femmes. Les domaines d'intérêt sont le dépistage, la dépendance et le sevrage; la communication et la tenue de dossier; la grossesse (y compris les issues fœtales et maternelles); la gestion de la douleur maternelle; les soins postnataux (y compris la fumée secondaire et la parentalité); et l'allaitement.

POPULATION CIBLE

Femmes enceintes, allaitantes ou qui planifient une grossesse. BéNéFICES, RISQUES ET COûTS: Discuter de l'utilisation de cannabis avec les femmes enceintes, allaitantes ou qui planifient une grossesse les aide à faire des choix éclairés. D'après des données probantes limitées, il faut éviter l'utilisation de cannabis pendant la grossesse ou l'allaitement, ou réduire la consommation au maximum si l'abstention n'est pas un objectif atteignable, étant donné l'absence de données sur l'innocuité et le suivi à long terme des grossesses et nourrissons exposés au cannabis. DONNéES PROBANTES: Les auteurs ont interrogé les bases de données PubMed et Cochrane Library pour extraire des articles sur l'utilisation de cannabis pendant la grossesse et l'allaitement publiés entre le 1^er janvier 2018 et le 5 février 2021. Les termes de recherche ont été déterminés à partir de termes de recherche MeSH, de mots clés et de leurs variantes : cannabis, cannabinoids, cannabidiol, CBD, THC, marijuana, edible, pregnancy, pregnant, prenatal, perinatal, postnatal, breastfeed, breastfed, lactation, nursing, fetus, fetal, neonatal, newborn et child. Les auteurs ont inclus toutes les publications des types suivants : essais cliniques, études observationnelles, revues (y compris les revues systématiques et les méta-analyses), directives cliniques et déclarations de conférences de consensus. Les principaux critères d'inclusion étaient les femmes enceintes et allaitantes, comme population cible, et l'exposition au cannabis, comme intervention d'intérêt. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique d'évaluation, de développement et d'évaluation (GRADE). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et faibles). PROFESSIONNELS CONCERNéS: Tous les fournisseurs de soins de santé qui prodiguent des soins aux femmes en âge de procréer. DÉCLARATIONS SOMMAIRES: RECOMMANDATIONS.

Beliefs about marijuana use during pregnancy and breastfeeding held by residents of a Latino-majority, rural region of California

Marijuana use among pregnant and breastfeeding women is on the rise and carries risks for infant health and well-being. Decisions to use marijuana while pregnant and breastfeeding are motivated by beliefs that use poses minimal risk to infants and offers benefits to maternal users. Misperceptions and usage trend higher among disadvantaged populations. This study surveyed 401 community residents on beliefs about risks and benefits of marijuana use by pregnant and breastfeeding women. The study utilized techniques to enhance recruitment of Latino and disadvantaged residents of rural communities in California, a state where recreational marijuana use is legal. Analyses revealed substantial endorsement of beliefs about benefits and low risks of marijuana use while pregnant and breastfeeding, many of which run counter to current evidence. Misperceptions were particularly prevalent for cannabis users and male respondents. Trends in valid beliefs, while modest, were higher for Latinos and parents.

Guideline No. 425b: Cannabis Use Throughout Women's Lifespans - Part 2: Pregnancy, the Postnatal Period, and Breastfeeding

OBJECTIVE

To provide health care providers with the best evidence on cannabis use and women's health. Areas of focus include screening, dependence, and withdrawal; communication and documentation; pregnancy (including maternal and fetal outcomes); maternal pain control; postpartum care (including second-hand smoking and parenting); and breastfeeding.

TARGET POPULATION

The target population includes women who are planning a pregnancy, pregnant, or breastfeeding.

BENEFITS, HARMS, AND COSTS

Discussing cannabis use with women who are planning a pregnancy, pregnant, or breastfeeding allows them to make informed choices about their cannabis use. Based on the limited evidence, cannabis use in pregnancy or while breastfeeding should be avoided, or reduced as much as possible if abstaining is not feasible, given the absence of safety and long-term follow up data on cannabis-exposed pregnancies and infants.

EVIDENCE

PubMed and Cochrane Library databases were searched for articles relevant to cannabis use during pregnancy and breastfeeding published between January 1, 2018, and February 5, 2021. The search terms were developed using the MeSH terms and keywords and their variants, including cannabis, cannabinoids, cannabidiol, CBD, THC, marijuana, edible, pregnancy, pregnant, prenatal, perinatal, postnatal, breastfeed, breastfed, lactation, nursing, fetus, fetal, neonatal, newborn, and child. In terms of publication type, all clinical trials, observational studies, reviews (including systematic reviews and meta-analyses), guidelines, and conference consensus statements were included. The main inclusion criteria were pregnant and breastfeeding women as the target population, and exposure to cannabis as the intervention of interest.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED AUDIENCE

All health care providers who care for women of reproductive age.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Psychotropic drug abuse in pregnancy and its impact on child neurodevelopment: A review

Substance abuse by women of child-bearing age and fetal in utero drug exposure has increased in the number of infants born with health issues. Prenatal exposure to psychoactive substances can lead to neurological and neurodevelopmental deficits later in life. Useful data concerning the effects of psychoactive drugs on fetal neurodevelopmental status are sparse. Understanding the neurodevelopmental consequences of prenatally drug-exposed children has become a pressing global concern. The aim of this review is to gather current evidence and information on neurodevelopmental outcomes of in utero drug exposure. A literature search was performed on the PubMed, Scopus, and Google Scholar databases using the terms “psychotropic drugs”, “neurodevelopmental consequences”, “prenatal drug exposure”, and “pregnancy”. Available studies on in utero drug exposure were reviewed and found to support the idea that some degree of health issues are present in fetuses and children. Different psychoactive substances have profound neurodevelopmental consequences, such as structural brain changes, poor attention span, Down syndrome, attention deficit hyperactivity disorder, autism spectrum disorder, imbalances in neurotransmitter levels, and many structural deficits. The pervasive use of psychoactive drugs in women of child-bearing age is an important health concern. Further scientific efforts are needed to investigate the effect of prenatal exposure to psychoactive drugs on children.

Applications of Cannabis Sativa L. in Food and Its Therapeutic Potential: From a Prohibited Drug to a Nutritional Supplement

Hemp (Cannabis sativa L.) is a herbaceous anemophilous plant that belongs to the Cannabinaceae family. The cannabis seed (hemp) has long been utilized as a food source and is commercially important as an edible oil source. In this review, the positive and negative health effects of cannabis, the relationship between cannabis and various diseases, and the use of cannabis in various food products have been discussed. In addition, the scientific literature on the potential use of cannabis and its derivatives as a dietary supplement for the prevention and treatment of inflammatory and chronic degenerative diseases in animals and humans has been reviewed. Cannabis is being developed as a key ingredient in a variety of food items, including bakery, confectionery, beverages, dairy, fruits, vegetables, and meat. Hemp seeds are high in readily digestible proteins, lipids, polyunsaturated fatty acids (PUFA), insoluble fiber, carbs, and favorable omega-6 PUFA acid to omega-3 PUFA ratio and have high nutritional value. The antioxidants of cannabis, such as polyphenols, help with anxiety, oxidative stress, and the risk of chronic illnesses, including cancer, neurological disorders, digestive problems, and skin diseases. Cannabis has been shown to have negative health impacts on the respiratory system, driving, and psychomotor functions, and the reproductive system. Overall, the purpose of this research is to stimulate more in-depth research on cannabis's adaptation in various foods and for the treatment of chronic illnesses.

[Effect of Psychosocial Factors on Growth]

BACKGROUND

Genes, hormones and factors such as nutrition and psychosocial environment affect growth.

OBJECTIVE

What is the significance of various psychosocial factors on growth?

METHODS

Evaluation of results of a working meeting of paediatric endocrinologist with current literature research.

RESULTS

Psychosocial deprivation in children can be associated with growth hormone deficiency (GHD) and short stature. GHD can be reversed by a change of environment and psychosocial support. War and migration are often associated with underweight, growth disturbances and poor health care. These factors can improve after the end of conflicts, but children often remain too short. Consumption of alcohol or opiates during pregnancy are associated with lower birth weight and increased risk of early and small for gestational age (SGA) childbirth. Children with attention deficit hyperactivity disorder show a slight slowdown in growth after they started stimulant therapy. However, they reach normal adult height.

CONCLUSIONS

In children with idiopathic short stature, psychosocial causes should be taken into account in the differential diagnosis. Notably there is an increased risk of growth disturbances in children from conflict regions or after prenatal drug exposure.

Effects of marijuana on reproductive health: preconception and gestational effects

PURPOSE OF REVIEW

Recent widespread legalization changes have promoted the availability of marijuana and its increased potency and perceived safety. The limited evidence on reproductive and perinatal outcomes from marijuana exposure is enough to warrant concern and action. The objective of this review is to provide a current and relevant summary of the recent literature surrounding this topic.

RECENT FINDINGS

The available published studies on the effect of marijuana exposure on reproductive health and pregnancy outcomes are conflicting. Human studies are often observational or retrospective and confounded by self-report and polysubstance use. However, the current, limited evidence suggests that marijuana use adversely affects male and female reproductive health. Additionally, prenatal marijuana exposure has been reported to be associated with an increased risk of preterm birth and small for gestational age infants.

SUMMARY

With the increasing prevalence of marijuana use, there is an urgent need for evidence-driven recommendations and guidelines for couples interested in conception, affected by infertility or who are expecting. At this time, no amount of marijuana use during conception or pregnancy is known to be well tolerated and the limited available evidence suggests that the safest choice is to abstain.

The associations between prenatal cannabis use disorder and neonatal outcomes

BACKGROUND AND AIMS

Cannabis use disorder (CUD) during pregnancy has increased dramatically in the United States (US). This study examined the associations between prenatal CUD and adverse neonatal outcomes and heterogeneities in the associations by mothers' tobacco use status and race/ethnicity.

DESIGN

Population-based, retrospective cohort study.

SETTING

California, USA.

PARTICIPANTS

A total of 4.83 million mothers who delivered a live singleton birth during 2001 to 2012 and their paired infants. Data were obtained from mother-infant linked hospital discharge records and birth and death certificates. Identified by ICD-9 codes recorded at delivery, 20 237 mothers had prenatal CUD.

MEASUREMENTS

Neonatal outcomes included length of gestation, preterm birth, birth weight, admission into neonatal intensive care unit, hospitalization within 1 year of birth, and death within 1 year of birth. Propensity score matching was used to balance maternal, paternal, and infant characteristics in the comparisons between infants exposed and unexposed to prenatal CUD.

FINDINGS

CUD increased from 2.8 to 6.9 per 1000 deliveries during 2001 to 2012. Multivariable regressions in matched samples estimated that prenatal CUD was associated with greater odds of being small for gestational age (OR = 1.13, 95% CI = 1.08, 1.18), preterm birth (OR = 1.06, 95% CI = 1.01, 1.12), low birth weight (OR = 1.13, 95% CI = 1.07, 1.20), and death within 1 year of birth (OR = 1.35, 95% CI = 1.12, 1.62). Compared with infants whose mothers were tobacco non-users, infants whose mothers were tobacco users had greater odds of preterm birth, low birth weight, hospitalization, and death in association with prenatal CUD. Compared with infants whose mothers were non-Hispanic White, infants whose mothers were Hispanic had greater odds of hospitalization and death and infants whose mothers were non-Hispanic Black had greater odds of being small for gestational age in association with prenatal CUD.

CONCLUSION

Prenatal cannabis use disorder appears to be associated with escalated odds of major adverse neonatal outcomes, with heterogeneities in the associations by mothers' tobacco use status and race/ethnicity.

Explaining the Black-White Disparity in Preterm Birth: A Consensus Statement From a Multi-Disciplinary Scientific Work Group Convened by the March of Dimes

In 2017–2019, the March of Dimes convened a workgroup with biomedical, clinical, and epidemiologic expertise to review knowledge of the causes of the persistent Black-White disparity in preterm birth (PTB). Multiple databases were searched to identify hypothesized causes examined in peer-reviewed literature, 33 hypothesized causes were reviewed for whether they plausibly affect PTB and either occur more/less frequently and/or have a larger/smaller effect size among Black women vs. White women. While definitive proof is lacking for most potential causes, most are biologically plausible. No single downstream or midstream factor explains the disparity or its social patterning, however, many likely play limited roles, e.g., while genetic factors likely contribute to PTB, they explain at most a small fraction of the disparity. Research links most hypothesized midstream causes, including socioeconomic factors and stress, with the disparity through their influence on the hypothesized downstream factors. Socioeconomic factors alone cannot explain the disparity's social patterning. Chronic stress could affect PTB through neuroendocrine and immune mechanisms leading to inflammation and immune dysfunction, stress could alter a woman's microbiota, immune response to infection, chronic disease risks, and behaviors, and trigger epigenetic changes influencing PTB risk. As an upstream factor, racism in multiple forms has repeatedly been linked with the plausible midstream/downstream factors, including socioeconomic disadvantage, stress, and toxic exposures. Racism is the only factor identified that directly or indirectly could explain the racial disparities in the plausible midstream/downstream causes and the observed social patterning. Historical and contemporary systemic racism can explain the racial disparities in socioeconomic opportunities that differentially expose African Americans to lifelong financial stress and associated health-harming conditions. Segregation places Black women in stressful surroundings and exposes them to environmental hazards. Race-based discriminatory treatment is a pervasive stressor for Black women of all socioeconomic levels, considering both incidents and the constant vigilance needed to prepare oneself for potential incidents. Racism is a highly plausible, major upstream contributor to the Black-White disparity in PTB through multiple pathways and biological mechanisms. While much is unknown, existing knowledge and core values (equity, justice) support addressing racism in efforts to eliminate the racial disparity in PTB.

Association between preconception cannabis use and risk of postpartum depression: Findings from an Australian longitudinal cohort

BACKGROUND AND AIM

Evidence suggests a positive association between cannabis use and depression however whether preconception cannabis use is associated with postpartum depression (PPD) remains unknown. This study examined the association using a longitudinal design.

METHODS

Participants were from the Australian Longitudinal Study on Women's Health (cohort born in 1989-95), a sample broadly representative of similarly aged Australian women. The association of past year cannabis use at 3-15 months prior to pregnancy with PPD at ages 19-24 to 22-27 was examined in 516 women with 570 singleton live births. The associations of chronicity, recency, and initiation of cannabis use before pregnancy with PPD at ages 21-26 to 24-29 were investigated in 538 women with 590 singleton live births. PPD was ascertained from self-report of doctor diagnosis for each birth. Relative risk (RR) and 95 % confidence interval (CI) were used to calculate the associations of interest.

RESULTS

Compared with no cannabis use, any past-year cannabis use at 3-15 months before pregnancy may be associated with an increased risk of PPD (1.50, 0.99-2.28). Compared with no cannabis use in the first three annual surveys before pregnancy, chronic use (a past year user in ≥ 2 surveys) was associated with an 80 % higher risk of incident PPD for births in the following 1-4 years (1.80, 1.22-2.68). Compared to never users at ages 20-25, former users who had no use within the past year had no increased risk; past year users had 73 % higher risk (1.73, 1.07-2.81); and past year users who initiated cannabis use at or after age 18 had twice the risk of incident PPD for births in the following 1-4 years (2.02, 1.17-3.49).

CONCLUSION

This study provides evidence that preconception cannabis use is associated with increased risk of PPD. More studies are warranted to confirm this finding before cannabis cessation policies can be reinforced on reducing the risk of PPD.

Cannabis and tobacco use prior to pregnancy and subsequent offspring birth outcomes: a 20-year intergenerational prospective cohort study

There is increasing evidence that the life-course origins of health and development begin before conception. We examined associations between timing and frequency of preconception cannabis and tobacco use and next generation preterm birth (PTB), low birth weight (LBW) and small for gestational age. 665 participants in a general population cohort were repeatedly assessed on tobacco and cannabis use between ages 14-29 years, before pregnancy. Associations were estimated using logistic regression. Preconception parent (either maternal or paternal) daily cannabis use age 15-17 was associated with sixfold increases in the odds of offspring PTB (aOR 6.65, 95% CI 1.92, 23.09), and offspring LBW (aOR 5.84, 95% CI 1.70-20.08), after adjusting for baseline sociodemographic factors, parent sex, offspring sex, family socioeconomic status, parent mental health at baseline, and concurrent tobacco use. There was little evidence of associations with preconception parental cannabis use at other ages or preconception parental tobacco use. Findings support the hypothesis that the early life origins of growth begin before conception and provide a compelling rationale for prevention of frequent use during adolescence. This is pertinent given liberalisation of cannabis policy.

The Impact of Early Life Exposure to Cannabis: The Role of the Endocannabinoid System

Cannabis use during pregnancy has continued to rise, particularly in developed countries, as a result of the trend towards legalization and lack of consistent, evidence-based knowledge on the matter. While there is conflicting data regarding whether cannabis use during pregnancy leads to adverse outcomes such as stillbirth, preterm birth, low birthweight, or increased admission to neonatal intensive care units, investigations into long-term effects on the offspring’s health are limited. Historically, studies have focused on the neurobehavioral effects of prenatal cannabis exposure on the offspring. The effects of cannabis on other physiological aspects of the developing fetus have received less attention. Importantly, our knowledge about cannabinoid signaling in the placenta is also limited. The endocannabinoid system (ECS) is present at early stages of development and represents a potential target for exogenous cannabinoids in utero. The ECS is expressed in a broad range of tissues and influences a spectrum of cellular functions. The aim of this review is to explore the current evidence surrounding the effects of prenatal exposure to cannabinoids and the role of the ECS in the placenta and the developing fetus.

The Effects of Cannabis on Female Reproductive Health Across the Life Course

Introduction: Cannabis is commonly used for its medicinal and therapeutic benefits and is also widely used as a recreational drug. Cannabis use has been increasing in Canada, including among Canadian women of reproductive age. Post-legalization, further increases in cannabis use are expected due to increased availability and lowered perceptions of harm. Although cannabinoids are well known for their effects on the central and peripheral nervous systems, endocannabinoid receptors have also been characterized throughout the female reproductive tract. Cannabinoids may affect many aspects of female reproductive health, including fertility, pregnancy outcomes with neonatal implications, and menopause. Purpose: To provide a comprehensive review of trends in cannabis use among women and review the impact of cannabis across the female reproductive lifespan. Methods: We searched PubMed and Cochrane Library databases using keywords and MeSH terms. Included studies reported the potential impact of cannabinoids on female fertility, pregnancy, transmission to breast milk, neonatal outcomes, and menopause. Results: The existing literature is primarily concentrated on the effect of cannabis use in pregnancy and breastfeeding, with little exploration of its impact on fertility and in later life. Studies are limited in number, with small sample sizes, and are hampered by methodological challenges related to confounding and other potential biases. Conclusions: There remain critical gaps in the literature about the potential risks of cannabis use, particularly in vulnerable populations, including pregnant women, women who are breastfeeding, and their infants. Given the rise in the prevalence of cannabis use, new, robust investigations into the consequences of cannabis exposure on female reproductive health are needed.

Perceptions on acceptability and reported consumption of marijuana by blood donors prior to donation in the recreational use state of Colorado, USA

BACKGROUND AND OBJECTIVES

Blood donor opinions and behaviours regarding marijuana use are not well known nor is the potential impact to the blood supply. We sought to assess opinions and frequency of marijuana use in proximity to blood donation via a survey of blood donors at a hospital-based blood collection site in a state where recreational marijuana use has been legal since 2012.

MATERIALS AND METHODS

Blood donors at least 18 years of age who donated between 2014 and 2019 were surveyed electronically, with all responses kept anonymous to encourage engagement and accurate reporting.

RESULTS

Overall response rate was 8.03% (12,186 surveys sent with 979 responses). Of responding donors, 23.5% indicated that they felt that consuming various forms of marijuana was acceptable prior to blood donation. Marijuana use <72 h prior to blood donation was reported in all demographic groups surveyed except age 18-24 years. Of donors who reported daily marijuana use, 47.4% indicated >20 donations and 52.6% indicated apheresis platelet donation.

CONCLUSION

Nearly one quarter of responding blood donors feel that marijuana use is acceptable prior to blood donation, and nearly every demographic group surveyed indicated use of marijuana <72 h prior to donation. These results suggest the need for additional research to determine if marijuana-related metabolites in collected blood products negatively impact recipients, particularly vulnerable populations such as children and pregnant women. These results may inform whether changes in donor screening or testing for marijuana use are warranted.

Endocannabinoid System in Pregnancy Maintenance and Labor: A Mini-Review

The endocannabinoid system (ECS) is a cell-signaling system present in multiple organ systems and is an integral part of sustaining the microenvironment necessary for early pregnancy success and maintenance. It plays a significant role in embryo development, transport and implantation as well as placentation. The current theory behind the initiation of term labor is that it is a complex, multifactorial process involving sex steroid hormones, prostaglandin production and interplay at the maternal-fetal interface resulting in increased expression of receptors and gap junctions that promote uterine activation. There is increasing evidence that, in addition to early pregnancy events, the ECS plays a regulatory role in pregnancy maintenance and the timing of labor. This review presents an overview of the ECS in pregnancy that focuses on late gestation and parturition.

Cannabis and Cannabinoids in Reproduction and Fertility: Where We Stand

Although cannabis use is increasing in general population, their prevalence among young adults is remarkably high. In recent years, their medical use gained a renewed interest. However, it can underline the reputation of cannabis being a harmless drug. Between cannabinoids, uniquely found on the cannabis plant, Δ⁹-tetrahydrocannabinol (THC) is the well-studied compound. It is responsible for the psychoactive effects via central cannabinoid receptors. Nevertheless, cannabinoids interact with other chemical signalling systems such as the hypothalamic-pituitary-gonadal axis. THC indirectly decreases gonadotropin-releasing hormone (GnRH) secretion by the hypothalamus. The consequences are diverse, and several key hormones are affected. THC disturbs important reproductive events like folliculogenesis, ovulation and sperm maturation and function. Although generally accepted that cannabinoid consumption impacts male and female fertility, prevailing evidence remains largely on pre-clinical studies. Here, we introduce cannabinoids and the endocannabinoid system, and we review the most prominent clinical evidence about cannabis consumption in reproductive potential and teratogenicity.

Frequency of cannabis use during pregnancy and adverse infant outcomes, by cigarette smoking status - 8 PRAMS states, 2017

BACKGROUND

Research on prenatal cannabis use and adverse infant outcomes is inconsistent, and findings vary by frequency of use or cigarette use. We assess (1) the prevalence of high frequency (≥once/week), low frequency (

METHODS

Cross-sectional data from 8 states' 2017 Pregnancy Risk Assessment Monitoring System (n = 5548) were analyzed. We calculated adjusted prevalence ratios (aPR) between cannabis use frequency and infant outcomes with Modified Poisson regression.

RESULTS

Approximately 1.7 % and 2.6 % of women reported low and high frequency prenatal cannabis use, respectively. Prevalence of use was higher among women with small-for-gestational age (SGA) (10.2 %) and low birthweight (9.7 %) deliveries, and cigarette use during pregnancy (21.2 %). Among cigarette smokers (aPR: 1.8; 95 % CI: 1.1-3.0) and non-smokers (aPR: 2.1; 95 % CI: 1.1-3.9), high frequency cannabis use doubled the risk of low birthweight delivery but did not increase preterm or SGA risk. Regardless of cigarette use, low frequency cannabis use did not significantly increase infant outcome risk.

CONCLUSIONS

Prenatal cannabis use was more common among women who smoked cigarettes during pregnancy. High frequency cannabis use was associated with low birthweight delivery, regardless of cigarette use. Healthcare providers can implement recommended substance use screening and provide evidence-based counseling and cessation services to help pregnant women avoid tobacco and cannabis use.

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Key Words

• Cannabis
• Low birthweight
• Maternal
• Prenatal
• Preterm birth
• Small for gestational age

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MESH Headings

• Adult
• Cannabis
• Cigarette Smoking/epidemiology
• Cross-Sectional Studies
• Female
• Health Behavior
• Humans
• Infant, Newborn
• Infant, Small for Gestational Age
• Marijuana Use/epidemiology
• Pregnancy
• Premature Birth/epidemiology
• Prevalence
• Risk Assessment
• Tobacco Products
• United States/epidemiology
• Young Adult

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Grants

• CC999999 Intramural CDC HHS

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Affiliation(s)

Sarah C Haight Division of Reproductive Health, National Center for Chronic Disease and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, United States.
Brian A King The Office on Smoking and Health, National Center for Chronic Disease and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, United States
Jennifer M Bombard Division of Reproductive Health, National Center for Chronic Disease and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, United States
Kelsey C Coy Division of Reproductive Health, National Center for Chronic Disease and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, United States; Oak Ridge Institute for Science and Education, US Department of Energy, United States
Cynthia D Ferré Division of Reproductive Health, National Center for Chronic Disease and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, United States
Althea M Grant Office of the Director, Deputy Director for Non-Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States; United States Public Health Service, Commissioned Corps, Rockville, MD, United States
Jean Y Ko Division of Reproductive Health, National Center for Chronic Disease and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, United States; United States Public Health Service, Commissioned Corps, Rockville, MD, United States

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Delta-9-tetrahydrocannabinol inhibits invasion of HTR8/SVneo human extravillous trophoblast cells and negatively impacts mitochondrial function

Prenatal cannabis use is a significant problem and poses important health risks for the developing fetus. The molecular mechanisms underlying these changes are not fully elucidated but are thought to be attributed to delta-9-tetrahydrocannabinol (THC), the main bioactive constituent of cannabis. It has been reported that THC may target the mitochondria in several tissue types, including placental tissue and trophoblast cell lines, and alter their function. In the present study, in response to 48-h THC treatment of the human extravillous trophoblast cell line HTR8/SVneo, we demonstrate that cell proliferation and invasion are significantly reduced. We further demonstrate THC-treatment elevated levels of cellular reactive oxygen species and markers of lipid damage. This was accompanied by evidence of increased mitochondrial fission. We also observed increased expression of cellular stress markers, HSP70 and HSP60, following exposure to THC. These effects were coincident with reduced mitochondrial respiratory function and a decrease in mitochondrial membrane potential. Taken together, our results suggest that THC can induce mitochondrial dysfunction and reduce trophoblast invasion; outcomes that have been previously linked to poor placentation. We also demonstrate that these changes in HTR8/SVneo biology may be variably mediated by cannabinoid receptors CB1 and CB2.

Canadian educational resources about cannabis use and fertility, pregnancy and breast feeding: a scoping review protocol

INTRODUCTION

Cannabis use in Canada is becoming more prevalent across all demographic groups due to increases in accessibility and lowered perceptions of harm. These patterns are mirrored among women of reproductive age, including women who are pregnant. Given increasing evidence for detrimental short- and long-term impacts of cannabis exposure on fetal, newborn and child outcomes, there is a need for high-quality, accessible resources providing reliable guidance and recommendations on this topic for both the public and healthcare providers. We will conduct a scoping review to identify and characterise all publicly available online educational resources discussing cannabis use related to fertility, pregnancy and breastfeeding developed by Canadian organisations.

METHODS AND ANALYSIS

Using Arksey and O'Malley's scoping review methodology as a guide, we will search Medline (Ovid), Medline in Process (Ovid), Embase (Ovid), ERIC (Ovid), CINAHL (EBSCOhost) and Education Source (EBSCOhost). We will also conduct a grey literature search targeting the websites of national and independent Canadian obstetrical societies and networks, and government and public health offices that provide recommendations or guidance to individuals and their healthcare providers seeking information on cannabis use related to fertility, pregnancy or breastfeeding.

ETHICS AND DISSEMINATION

Research ethics approval is not required for scoping review studies. We anticipate that this review's findings will be disseminated through traditional channels, including preprint and peer-reviewed publications and presentations at academic conferences. In addition, the resources and guidelines identified in the study will be gathered and made available online on a single comprehensive public repository. PROTOCOL REGISTRATION NUMBER: osf.io/p24y5.

Maternal Marijuana Exposure and Birth Weight: An Observational Study Surrounding Recreational Marijuana Legalization

OBJECTIVE

This study aimed to study the relationship between prenatal marijuana and infant birth weight using natural cohorts established before, during and after the 20-month lapse between legalization and legal recreational sales in Washington State.

STUDY DESIGN

Over 5 years, 5,343 pregnant women with documented urine drug screen (UDS) results delivered at Tacoma General Hospital or Good Samaritan Hospital. Maternal medical data were extracted for three delivery cohorts established based on before (T1), during (T2), and after legalization (T3) of recreational marijuana and legalized availability. Univariate and multivariate models were created to study marijuana exposure on infants' birth weight.

RESULTS

Marijuana exposure increased the risk of low birth weight (LBW; odds ratio [OR] = 1.42, 95% confidence interval [CI]: 1.01-2.01). This was more pronounced in full-term babies (OR = 1.72, 95% CI: 1.10-2.69), and was independently associated with a higher risk for small for gestational age (SGA; OR = 1.51, 95% CI: 1.49-1.53). The associations between marijuana exposure and SGA were maintained in cohort-specific models (OR = 1.53, 95% CI: 1.01-2.32 for T2, and OR = 1.43, 95% CI: 1.01-2.02 for T3, respectively).

CONCLUSION

Marijuana exposure verified by UDS was associated with LBW and SGA. However, recreational marijuana legalization and availability did not have direct impact on newborns' risk of LBW or SGA.

Association between gestational cannabis exposure and maternal, perinatal, placental, and childhood outcomes

Globally, the availability and formulations for the administration of cannabis are changing with decriminalization or legalization of recreational use in some jurisdictions, and the prescription of cannabis also occurring. These changes are likely to affect the prevalence of use, including by women of childbearing age. The effects of in utero and infant alcohol and tobacco exposure are well-documented, but the outcomes of cannabis exposure are less certain. The content of delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis has progressively increased over several decades. This review explores the limited knowledge surrounding the epidemiology of gestational and postnatal cannabis exposure and implications for the mother-placenta-fetus/neonate triad. We examine cannabis' effects from antenatal and lactation exposure on (a) pregnancy and perinatal outcomes, (b) placental health, and (c) longer term cardiometabolic and neurodevelopmental risks and outcomes. Though definitive outcomes are lacking, gestational cannabis has been associated with increased risk of other substance use during pregnancy; impaired placental blood flow; increased risk of small for gestational age births; and associated complications. Childhood and adolescent outcomes are sparsely assessed, with suggested outcomes including increased risk of depression and attention-deficit hyperactivity disorder. Cardiometabolic implications of gestational cannabis use may include maternal fatty liver, obesity, insulin resistance, and increased risk of gestational diabetes mellitus (GDM), with potential consequences for the fetus. Clinical implications for pediatric practice were explored in a bid to understand any potential risk or impact on child health and development.

Demographic Discrepancies in Prenatal Urine Drug Screening in Washington State Surrounding Recreational Marijuana Legalization and Accessibility

OBJECTIVES

This study evaluated demographic patterns related to prenatal cannabinoid urine drug screening (UDS) over a 5-year period during which recreational marijuana was legalized and became accessible in Washington State.

METHODS

Using electronic health record data, we performed a retrospective analysis for deliveries occurring over a 5-year period that encapsulated the transitions to marijuana legalization and legal access. For three cohorts of women delivering prior to legalization, between legalization and accessibility, and following accessibility, the UDS completion rate and screening demographic characteristics were assessed using Chi-squared tests and multivariate logistic regression.

RESULTS

25,514 deliveries occurred between March 2011 and March 2016. A significantly higher percentage of women underwent UDS post-accessibility (24.5%) compared to pre-legalization (20.0%, p < 0.001). A corresponding increase was not observed in the percentage of marijuana-positive UDS in tested patients (22.7% vs. 23.3%, p = 0.86). African American women had 2.8 times higher odds than Latinas of being tested, 2.1 times higher odds than Asian women, 1.7 times higher odds than White women, and 1.4 times higher odds than women of other races (all p < 0.001). Subsidized insurance status was also strongly associated with increased likelihood of testing (aOR = 3.5, p < 0.001).

CONCLUSIONS FOR PRACTICE

Prenatal UDS testing patterns changed as recreational marijuana possession and accessibility became legal. Demographic discrepancies in testing reveal biases related to race and insurance status, which may be a proxy for socioeconomic status. As such discrepancies are potential contributors to health outcome disparities, it is important for providers and health care systems to examine their practices and ensure they are being appropriately, equally, and justly applied.

Cannabis Exposure During Critical Windows of Development: Epigenetic and Molecular Pathways Implicated in Neuropsychiatric Disease

PURPOSE OF REVIEW

Cannabis exposure during critical windows of development may have intergenerational physiological consequences disrupting epigenetic programming and marks. This review examines the literature relating to pre-gestational and prenatal cannabinoid exposure and its effect on genes and molecular pathways related to the development of psychiatric disease.

RECENT FINDINGS

Developmental cannabis exposure alters epigenetic processes with functional gene consequences. These include potentially heritable alterations in genes and molecular pathways critical for brain development and associated with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), schizophrenia, addiction, and other psychiatric diseases. Cannabis consumption and mental health illness in adolescents and young adults are increasing in the United States (U.S.), and recent studies suggest that cannabis consumption during critical periods of brain development could contribute to mental health illness through epigenetic mechanisms. These findings warrant future studies and consideration by regulators and health communicators.

Marijuana use and pregnancy outcomes among women with hypertension in pregnancy

Background: Marijuana has vasoconstrictive properties and its use has been associated with increased blood pressure in the general population. Yet, there are limited data on marijuana use and adverse outcomes among women with hypertension in pregnancy, even though these disorders are associated with severe maternal and fetal morbidity and mortality. Since marijuana is currently the most commonly used illicit drug in pregnancy, there is an urgent need to better understand the potential association between marijuana use and hypertension in pregnancy.Objective: To determine the adverse prenatal effects of marijuana use in women with hypertension in pregnancy.Study design: We conducted a retrospective cohort study among individuals with hypertension in pregnancy that delivered ≥23 weeks' gestation at Oregon Health & Science University (October 2013-September 2018). The primary exposure assessed was marijuana use, identified by chart review of documented patient self-report or positive urine toxicology screen. Individuals were stratified into two groups by marijuana use: use during pregnancy versus never used. Primary outcomes included composite adverse maternal and neonatal outcomes. Secondary outcomes included individual maternal outcomes, rarer neonatal outcomes and severe features of preeclampsia. Differences were analyzed by Fisher's exact, t-test, and logistic regression. Significance was determined by alpha = 0.05 for primary outcomes and alpha = 0.01 for secondary outcomes.Results: From 11,825 deliveries, 1,613 (13.6%) were classified with hypertension in pregnancy. A total of 117 individuals (7.3%) used marijuana during pregnancy, 1,110 (68.2%) had never used marijuana and 396 (24.6%) had unknown marijuana use and were excluded, leaving 1,217 individuals in this analysis. Women using marijuana in pregnancy were more likely to be younger, non-Hispanic White, publicly insured and using other substances compared to women who did not use marijuana. There were no differences in the overall distribution of hypertensive disorders, including preeclampsia with severe features, in women who used marijuana versus those who did not (p = .80). In multivariable analyses, after adjusting for maternal factors and other substance use, marijuana use was not associated with adverse maternal (aOR 1.23, 95% CI 0.43-3.50, p = .69) or neonatal (aOR 0.90, 95% CI 0.28-2.89, p = .86) outcomes.Conclusions: Marijuana use in pregnancy was not associated with maternal or neonatal outcomes or worsened hypertensive disease among women with hypertension in pregnancy after adjusting for maternal characteristics, including use of other substances. Our data highlight the need to consider use of other substances when evaluating the association between marijuana use in pregnancy and adverse pregnancy outcomes.

Association of Maternal Opioid Use in Pregnancy With Adverse Perinatal Outcomes in Ontario, Canada, From 2012 to 2018

IMPORTANCE

A recent epidemic of opioid abuse has been described in many communities, although population-based data on trends in use in pregnancy and perinatal outcomes after in utero exposure remain limited.

OBJECTIVE

To assess trends in prenatal opioid use and the potential association between prenatal opioid use and preterm birth and adverse perinatal outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study covered live births and stillbirths among adolescents and women 15 years and older from April 1, 2012, to March 31, 2018, in Ontario, Canada. Data were analyzed from July 29 to October 15, 2019.

EXPOSURES

Any opioid use in pregnancy, ascertained through self-reporting and routine prenatal care.

MAIN OUTCOME AND MEASURES

The primary outcome was preterm birth before a gestational age of 37 weeks. Separate indicators for birth occurring at gestational ages of 34 to 36 weeks (plus 6 to 7 days; late preterm), 32 to 33 weeks (plus 6 to 7 days), 28 to 31 weeks (plus 6 to 7 days), and less than 28 weeks (very preterm birth). Secondary outcomes included small for gestational age, stillbirth, transfer to neonatal intensive care, and 5-minute Apgar score. Coarsened exact matching techniques and Poisson regression models were used to estimate the risk difference and relative risk (RR) of outcomes associated with cannabis exposure to control for confounding.

RESULTS

Among 710 911 women included in the analytic sample (mean [SD] age, 30.4 [5.3] years), 8059 used opioids (1.1%), with prevalence decreasing from 1.31% (95% CI, 1.25%-1.38%) in fiscal year 2012-2013 to 1.05% (95% CI, 0.99%-1.11%) in fiscal year 2017-2018 (P < .001 for trend). Use was highest among women in the lowest quintile of area-level income (2.36% vs 0.56% in the highest quintile; RR, 3.86; 95% CI, 3.58-4.15) and did not decrease over time in this group (from 2.63% [95% CI, 2.41%-2.87%] in 2012-2013 to 2.35% [95% CI, 2.14%-2.58%] in 2017-2018; P = .23 for trend). The crude rate of preterm birth at a gestational age of less than 37 weeks was 14.0% (n = 1127) among women with reported use in pregnancy and 6.0% (n = 42 226) among women who did not use opioids in the unmatched cohort. The adjusted RR for preterm birth before a gestational age of 37 weeks was 1.63 (95% CI, 1.52-1.75) among opioid users compared with nonusers and 1.77 (95% CI, 1.35-2.31) for preterm birth before 32 weeks. Among newborns, risk for neonatal intensive care was 40.5% with perinatal exposure to opioids compared with 13.9% in unexposed infants (RR, 2.91; 95% CI, 2.80-3.03).

CONCLUSIONS AND RELEVANCE

Rates of opioid use in pregnancy have declined in recent years, although use remains significantly higher among lower-income women. In this large population-based cohort, opioid use in pregnancy was associated with an increased risk of preterm birth and admission to a neonatal intensive care unit.

The deleterious effects of cannabis during pregnancy on neonatal outcomes

OBJECTIVES

To evaluate whether cannabis use during pregnancy is associated with adverse neonatal outcomes that are independent of cigarette smoking.

DESIGN

Prospective cohort study.

SETTING

Adelaide (Australia), Auckland (New Zealand), Cork (Ireland), and Leeds, London and Manchester (United Kingdom).

PARTICIPANTS

5610 pregnant nulliparous women with low risk pregnancies recruited for the Screening for Pregnancy Endpoints (SCOPE) study, November 2004 - February 2011. At 14-16 weeks of pregnancy, women were grouped by self-reported cannabis use.

MAIN OUTCOME MEASURES

Infant birthweight, head circumference, birth length, gestational age, and severe neonatal morbidity or mortality.

RESULTS

314 women (5.6%) reported using cannabis in the 3 months before or during their pregnancy; 97 (31%) stopped using it before and 157 (50%) during the first 15 weeks of pregnancy, while 60 (19%) were still using cannabis at 15 weeks. Compared with babies of mother who had never used cannabis, infants of those who still used it at 15 weeks had lower mean values for birthweight (adjusted mean difference [aMD], -127 g; 95% CI, -238 to -17 g), head circumference (aMD, -0.5 cm; 95% CI, -0.8 to -0.1 cm), birth length (aMD, -0.8 cm; 95% CI, -1.4 to -0.2 cm), and gestational age at birth (aMD, -8.1 days; 95% CI, -12.1 to -4.0 days). The differences for all outcomes except gestational age were greater for women who used cannabis more than once a week than for those who used it less frequently.

CONCLUSIONS

Continuing to use cannabis during pregnancy is an independent risk factor for poorer neonatal outcomes.

Pregnant Canadians' Perceptions About the Transmission of Cannabis in Pregnancy and While Breastfeeding and the Impact of Information From Health Care Providers on Discontinuation of Use

OBJECTIVE

Rates of cannabis use during pregnancy and while breastfeeding are increasing in Canada. Some observational studies have found associations between cannabis use in pregnancy and low birthweight, preterm labour, and admission to the intensive care unit. This study aimed to evaluate women's perceptions about transmission of cannabis to the fetus, and whether receiving information from a health care provider influenced their decision to stop using cannabis during pregnancy.

METHODS

Pregnant women presenting to obstetrical, midwifery, and family practice clinics in the greater Hamilton, Ontario area were asked to complete an anonymous survey. Chi-square tests were used to investigate whether patient knowledge was influenced by health care providers or by self-directed learning and if this information influenced their decision to discontinue cannabis use.

RESULTS

Of the 478 women surveyed, the vast majority perceived that cannabis is transmitted to the fetus during pregnancy and to the infant while breastfeeding (94.3% and 91.2%, respectively). The majority of women (99%) indicated that the advent of cannabis legalization did not influence their choice to use cannabis in pregnancy. Women who continued to use cannabis during pregnancy were more likely to report receiving information on cannabis from a health care provider (52%) than those who chose to discontinue use in pregnancy (35%) (P = 0.035).

CONCLUSIONS

In our study, the proportion of pregnant women who understood that cannabis could be transmitted to the fetus in utero and to the infant via breastmilk was high. Despite this, 4.2% of women reported that they continued to use cannabis in pregnancy. More work is needed to understand why some women continue to use cannabis in pregnancy despite being informed of its risks.

Effects of marijuana on human reproduction

As U.S. states steadily legalize its distribution and the prevalence of its use in people of reproductive age continues to rise, the need to understand the effects of marijuana on human physiology is becoming increasingly urgent. While marijuana is well-known for its psychoactive effects and applications in controlling pain and nausea, little is known about its effects on reproduction. This review includes in vitro studies which consistently demonstrate associations between marijuana consumption and low sperm count, dysregulated menstruation, and abnormal placentation. While many in vivo studies associate maternal marijuana use with stillbirth, neonatal intensive care unit (NICU) admission, and offspring psychosis, significant literature negates these relationships by controlling for poly-substance use and socioeconomic status. Data limited by self-reporting and confounds precludes the drawing of definitive conclusions regarding the effects of marijuana on reproduction. This review serves as a call to action to elucidate these effects and discourage marijuana use in people of reproductive age.

Cannabis use in pregnancy and breastfeeding: The pharmacist's role

Background

The recent legalization of cannabis use in Canada requires pharmacists to be able to support their patients with accurate knowledge of its known risks and benefits. Certain populations, such as pregnant and breastfeeding women and their developing children, may be at higher risk than other populations.

Methods

The authors independently searched the literature for clinical reports or reviews of the literature regarding the safety of cannabis use in pregnancy and breastfeeding using search terms such as cannabis, marijuana, pregnancy and breastfeeding.

Results

This review combines the relevant pharmacological, pharmacokinetic and clinical evidence for the effects of cannabis in this special patient population. The literature demonstrates that some of the constituents of cannabis can reach children in utero and through breastmilk. Given that Δ⁹-tetrahydrocannabinol can be present in breastmilk as quickly as 1 hour after consumption and last up to 6 days, it may not be possible to use cannabis and avoid infant exposure. There is evidence that this exposure may result in cognitive, social and motor defects. Some of these effects may be long term, lasting years. The pharmacist must be able to educate and screen patients regarding marijuana use in pregnancy and breastfeeding, with the ultimate aim of harm reduction.

Marijuana Use in Pregnancy: A Review

Importance

Marijuana is the most commonly used dependent substance in pregnancy. The main active chemical of marijuana (delta-9-tetrahydrocannabinol [THC]) readily crosses the placenta, and cannabinoid receptors have been identified in fetal brain and placenta. As a result, prenatal marijuana use could potentially have detrimental impact on fetal development.

Objective

This review aims to summarize the existing literature and current recommendations for marijuana use while pregnant or lactating.

Evidence Acquisition

A PubMed literature search using the following terms was performed to gather relevant data: "cannabis," "cannabinoids," "marijuana," "fetal outcomes," "perinatal outcomes," "pregnancy," "lactation."

Results

Available studies on marijuana exposure in pregnancy were reviewed and support some degree of developmental disruption, including an increased risk of fetal growth restriction and adverse neurodevelopmental consequences. However, much of the existing prenatal marijuana research was performed in the 1980s, when quantities of THC were lower and the frequency of use was less. Additionally, most human studies are also limited and conflicting as most studies have been observational or retrospective, relying primarily on patient self-report and confounded by polysubstance abuse and small sample sizes, precluding determination of a causal effect specific for marijuana. Given the paucity of evidence, it is currently recommended to avoid using marijuana while pregnant or when breastfeeding.

Conclusion and Relevance

There is a critical need for research on effects in pregnancy using present-day THC doses. Once the adverse perinatal effects of marijuana exposure are identified and well characterized, patient education and antenatal surveillance can be developed to predict and mitigate its impact on maternal and fetal health.

[Focus on the endocannabinoid system and the reprotoxicity of marijuana in female users]

Among recreative compounds, marijuana is the most used worldwide. Delta9THC binding on brain endocannabinoid receptors drives its psychotropic effects. The endocannabinoid system (ECS) is an endogenous neurohormonal system essential for homeostasis composed of ligands, metabolic enzymes and at least 2 receptors discovered to date. In female reproduction, the ECS regulates the hypothalamic-pituitary axis and many steps of the reproduction process, such as ovulation, tubal transportation and trophoblast implantation. Delta9THC can cross the placental barrier and bind to the fetal endocannabinoid system. In humans, fetal and obstetrical consequences of marijuana use during pregnancy are intrauterine growth restriction and preterm delivery. In the light of legalization projects currently reviewed in several western countries, further research should be conducted to improve knowledge on maternal, fetal and reprotoxic consequences of marijuana use during reproductive age and pregnancy.

Cannabis Use in Pregnant and Breastfeeding Women: Behavioral and Neurobiological Consequences

Nowadays, cannabis is the most consumed illicit drug. The global prevalence of the use of cannabis in 2017 was estimated in 188 million of people, 3.8% of worldwide population. Importantly, the legalization of cannabis in different countries, together with the increase in the apparent safety perception, may result in a great variety of health problems. Indeed, an important concern is the increase in cannabis use among pregnant and breastfeeding women, especially since the content of delta9-tetrahidrocannabinol (THC) is currently around 2-fold higher than it was 15-20 years ago. The purpose of this study was to review cannabis use during pregnancy and breastfeeding including epidemiological aspects, therapeutic or preventive strategies, and experimental considerations and results from animal models of perinatal cannabis exposure to analyze the underlying neurobiological mechanisms and to identify new therapeutic approaches. A recent report revealed that among pregnant women aged 15-44, last month cannabis use prevalence was over 4.9%, raising to 8.5% in the 18-25-year-old age range. Pre- and post-natal exposure to cannabis may be associated with critical alterations in the newborn infants that are prolonged throughout childhood and adolescence. Briefly, several reports revealed that perinatal cannabis exposure was associated with low birth weight, reduction in the head circumference, cognitive deficits (attention, learning, and memory), disturbances in emotional response leading to aggressiveness, high impulsivity, or affective disorders, and higher risk to develop a substance use disorder. Furthermore, important neurobiological alterations in different neuromodulatory and neurotransmission systems have been associated with cannabis consumption during pregnancy and lactation. In spite of the evidences pointing out the negative behavioral and neurobiological consequences of cannabis use in pregnant and breastfeeding women, there are still limitations to identify biomarkers that could help to establish preventive or therapeutic approaches. It is difficult to define the direct association specifically with cannabis, avoiding other confusing factors, co-occurrence of other drugs consumption (mainly nicotine and alcohol), lifestyle, or socioeconomic factors. Therefore, it is necessary to progress in the characterization of short- and long-term cannabis exposure-related disturbances.

Cannabis use among women of reproductive age in the United States: 2002-2017

BACKGROUND

In this study of cannabis use in large nationally representative samples of United States (US) women aged 12-44 years, we evaluate variation by pregnancy month and by trimester. We also evaluate cannabis dependence, which might explain why some women continue using cannabis during pregnancy.

METHODS

Large nationally representative samples drawn for the US National Surveys on Drug Use and Health included 12-44-year-old women asked about pregnancy month, cannabis use, and cannabis dependence (n = 381,199). For this research, we produced month-specific estimates across four-time intervals (2002-2005, 2006-2009, 2010-2013, 2014-2017).

RESULTS

Overall from 2002 to 2017, estimates for non-pregnant women and for pregnant women in Trimester 1 indicate 7%-8% had used cannabis at least once in the 30 days prior to assessment. For pregnancy Month 1, the corresponding estimate is 11%, double Month 3 estimate of 5%. This degree of month-to-month variation is not seen for pregnant women in Trimesters 2 and 3, for whom estimates are 3% and 2%, respectively. Among women using cannabis during pregnancy, an estimated 19% have cannabis dependence, versus an expected value of 13% among non-pregnant women (p < .05).

CONCLUSION

Evidence of a possibly ameliorative pregnancy-associated reduction of cannabis use prevalence was seen by Month 3 during pregnancy. Cannabis dependence may help account for cannabis use early during pregnancy. Identification and outreach to reproductive age women with cannabis dependence might decrease prenatal cannabis exposure.

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

BACKGROUND

With expanding recreational cannabis legalisation, pregnant women and their offspring are at risk of potentially harmful consequences.

OBJECTIVES

To assess the prevalence of recreational cannabis use among pregnant women, health outcomes associated with prenatal recreational cannabis use, and the potential impact of recreational cannabis legalisation on this population.

SEARCH STRATEGY

Five databases and the grey literature were systematically searched (2000-2019).

SELECTION CRITERIA

Human studies published in English or French reporting on the prevalence of prenatal recreational cannabis use in high-income countries.

DATA COLLECTION AND ANALYSIS

Data on study characteristics, prenatal substance use, and health outcomes were extracted and qualitatively synthesised.

MAIN RESULTS

Forty-one publications met our inclusion criteria. The overall prevalence of prenatal cannabis use varied substantially (min-max: 0.24-22.6%), with the greatest use in the first trimester. In the three studies with temporal data available, rates of prenatal cannabis use increased across years. Only 7/41 and 5/41 studies provided information on gestational age of exposure and frequency of use, respectively. The concomitant use of alcohol, illicit drugs, and tobacco was higher among cannabis users than nonusers. Prenatal cannabis use was associated with select neonatal, but not maternal, health outcomes. There were insufficient data to compare prenatal cannabis use between the pre- and post-legalisation periods.

CONCLUSION

Cannabis use among pregnant women is prevalent and may be associated with adverse neonatal outcomes. Future studies should assess the gestational age and frequency of cannabis exposure, and usage patterns prior to and following legalisation.

TWEETABLE ABSTRACT

Women who consume cannabis during pregnancy could risk predisposing their newborns to poor birth outcomes.

Marijuana Use in Pregnancy and While Breastfeeding

The prevalence and perceived safety of marijuana use in pregnancy are increasing with expanding legalization. Marijuana crosses the placenta and passes into breast milk, resulting in fetal and neonatal exposure. Many women cite medical reasons for prenatal marijuana use such as nausea and vomiting of pregnancy, anxiety, and chronic pain. The scientific literature regarding marijuana in pregnancy is mixed, resulting in confusion among practitioners as to how to counsel women about risks of use. In addition, there is a paucity of literature related to marijuana use and breastfeeding. Existing pregnancy studies are predominantly retrospective cohorts with a reliance on self-report for ascertainment of exposure, which underestimates use. Many studies fail to adjust for important confounding factors such as tobacco use and sociodemographic differences. Despite the limitations of the existing evidence, there are animal and human data suggesting potential harm of cannabis use. The harms are biologically plausible given the role of the endocannabinoid system in pregnancy implantation, placentation, and fetal neurologic development. Two recent systematic reviews and meta-analyses found an association between marijuana use and adverse perinatal outcomes, especially with heavy marijuana use. In addition, three longitudinal cohort studies demonstrate a possible effect of prenatal marijuana exposure on long-term neurobehavioral outcomes. Marijuana use may be associated with growth restriction, stillbirth, spontaneous preterm birth, and neonatal intensive care unit admission. Therefore, women should be advised to refrain from using marijuana during pregnancy and lactation.