Maternal Cannabis Use Research Articles

P144. Prenatal Cannabis Use and Offspring Autism-Related Behaviors: Examining Maternal Stress as a Moderator in a Black American Cohort

The prevalence of both autism spectrum disorder (ASD) and maternal cannabis use during pregnancy are increasing, yet few empirical studies have examined their potential association. Moreover, it is unclear whether maternal prenatal cannabis use may interact with other ASD risk factors, such as maternal prenatal stress, to impact child neurodevelopment. This question is particularly relevant for Black mothers, who are disproportionately exposed to prenatal stressors including low socioeconomic status (SES) and racial discrimination.

Cannabis health survey on usage in women with spinal cord injury and knowledge among physicians: A cross-sectional study

Objective Individuals with spinal cord injury (SCI) report using cannabis to self-manage chronic pain and spasticity. However, its safety and efficacy are not well understood. As more women with SCI are pursuing motherhood, clinicians must consider the possibility of maternal cannabis use and its impact on fetal development. Moreover, due to the lack of current evidence for cannabis, it is important to characterize the perceptions and knowledge of physicians towards both recreational and synthetic cannabinoids. Design Two anonymous surveys (10-items each) were conducted. Setting and Participants Women with SCI (n = 20) completed an anonymous, online survey regarding cannabis use. Physicians at a Canadian SCI rehabilitation center (n = 15) completed a survey on their knowledge of recreational and synthetic cannabinoids among individuals with SCI. Outcome measures Survey 1 evaluated cannabis use patterns and perceptions before/after SCI in women, including during pregnancy and breastfeeding. The aim of Survey 2 was to understand the perception and current knowledge of physicians regarding recreational cannabis and synthetic cannabinoid use by patients with SCI. Results At the time of survey, 7 women with SCI reported use of cannabis, only 4 of them used prior to injury. Managing tone/spasticity (n = 5) was the major reported benefit of cannabis use. Women used cannabis during pregnancy and/or breastfeeding as a sleep aid or relief for morning sickness (n = 1 pregnancy, n = 1 breastfeeding, n = 1 both). The most-reported challenge with cannabis use was difficulty obtaining consistent, desirable effects (n = 5). Almost all physicians (n = 13) described their knowledge on recreational cannabis products as “none, very little or poor”, with greater overall comfort and knowledge of synthetic cannabinoids. Conclusion Due to the reported use of cannabis during pregnancy/breastfeeding and current impoverishment of physicians’ knowledge (particularly regarding recreational cannabis products), it is imperative to further investigate the safety and efficacy of cannabis use in women with SCI.

Maternal cannabis use during pregnancy and maternal and neonatal outcomes: A retrospective cohort study.

To examine the relationship between reported prenatal cannabis use and neonatal and maternal outcomes and whether the legalisation of cannabis in Canada affected the rates of reported use or the association with maternal and neonatal outcomes. Population-based retrospective cohort study. Routinely collected data in a real-world setting. All women in the Canadian province of Nova Scotia with singleton births between 1 January 2004 and 30 June 2021. The association between cannabis use and maternal and neonatal outcomes was examined using generalised linear models with inverse probability weighting. Maternal and neonatal outcomes in the peripartum and postpartum period. Rates of reported cannabis use in pregnancy increased from 1.3% to 7.5% over the study period with no appreciable change in slope after legalisation in 2018. Infants of mothers reporting cannabis use in pregnancy were more likely to have major anomalies and a 5-minute Apgar score ≤7, require neonatal intensive care unit admission, and had lower birthweight, head circumference and birth length than infants of mothers not reporting cannabis use. These associations did not differ before and after legalisation. Reported cannabis use during pregnancy is associated with early postnatal complications and reduced fetal growth, even after taking into account a range of confounding factors. Rates of reported cannabis use during pregnancy increased over the past 5years in Nova Scotia with no apparent additional effect of legalisation.

Cannabinoids accumulate in mouse breast milk and differentially regulate lipid composition and lipid signaling molecules involved in infant development

Maternal cannabis use during lactation may expose developing infants to cannabinoids (CBs) such as ∆-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). CBs modulate lipid signaling molecules in the central nervous system in age- and cell-dependent ways, but their influence on the lipid composition of breast milk has yet to be established. This study investigates the effects of THC, CBD, or their combination on milk lipids by analyzing the stomach contents of CD1 mouse pups that have been nursed by dams injected with CBs on postnatal days (PND) 1 -10. Stomach contents were collected 2 hours after the last injection on PND10 and HPLC/MS/MS was used to identify and quantify over 80 endogenous lipid species and cannabinoids in the samples. We show that CBs differentially accumulate in milk, lead to widespread decreases in free fatty acids, decreases in N-acyl methionine species, increases N-linoleoyl species, as well as modulate levels of endogenous CBs (eCBs) AEA, 2-AG, and their structural congeners. Our data indicate the passage of CBs to pups through breast milk and that maternal CB exposure alters breast milk lipid compositions.

Assessing THC passage and the impact in human perfused placenta cotyledons

Maternal cannabis use in pregnancy continues to increase with legalization. Frequent cannabis use in pregnancy is associated fetal growth restriction and low birth weight. The mechanism by which maternal cannabis use influences fetal growth remains unclear but is linked to the cannabinoid, Tetrahydrocannabinol (THC). Studies in animal models suggest exogenous THC crosses the placenta and observational human studies support these findings. The objectives of this study are to understand the mechanisms of THC transfer and its influence on fetal arterial vascular tone in human cotyledons.

Maternal trajectories of cannabis use and young adult cannabis and nicotine dependence

IntroductionThe goals of this study were to model maternal patterns of cannabis use from one year pre-pregnancy to 16 years postpartum and to determine if different patterns of maternal cannabis use predicted offspring substance use at age 22. MethodsWomen were recruited from a prenatal clinic between 1982 and 1984. Maternal cannabis use was assessed by trained interviewers twice during pregnancy, at delivery, 8 and 18 months, 3, 6, 10, 14, and 16 years postpartum. At age 22, substance use and dependence were measured in offspring. Growth mixture models of maternal cannabis use were calculated and adult offspring substance use outcomes were regressed onto maternal cannabis trajectory classes (n = 551). ResultsThere were five distinct patterns of maternal cannabis use. Offspring of mothers who were chronic cannabis users were more likely to use cannabis (p < 0.001) and develop CUD (p < 0.05) than offspring whose mothers did not use cannabis. Offspring of chronic cannabis users were also more likely to be nicotine dependent by age 22 than offspring whose mothers did not use cannabis (p < 0.01) and than offspring whose mothers were decreasingly likely to use over time (p < 0.01). ConclusionsIntegrated variable- and person-centered analyses revealed long-term and meaningful patterns of cannabis use and desistance. Chronic maternal cannabis use is a risk factor for regular and dependent cannabis use and for dependent tobacco use among young adult offspring. These findings have implications for maternal-child health given the increasing prevalence of cannabis use among women.

Maternal cannabis use is associated with suppression of immune gene networks in placenta and increased anxiety phenotypes in offspring

While cannabis is among the most used recreational drugs during pregnancy, the impact of maternal cannabis use (mCB) on fetal and child development remains unclear. Here, we assessed the effects of mCB on psychosocial and physiological measures in young children along with the potential relevance of the in utero environment reflected in the placental transcriptome. Children (∼3 to 6 y) were assessed for hair hormone levels, neurobehavioral traits on the Behavioral Assessment System for Children (BASC-2) survey, and heart rate variability (HRV) at rest and during auditory startle. For a subset of children with behavioral assessments, placental specimens collected at birth were processed for RNA sequencing. Hair hormone analysis revealed increased cortisol levels in mCB children. In addition, mCB was associated with greater anxiety, aggression, and hyperactivity. Children with mCB also showed a reduction in the high-frequency component of HRV at baseline, reflecting reduced vagal tone. In the placenta, there was reduced expression of many genes involved in immune system function including type I interferon, neutrophil, and cytokine-signaling pathways. Finally, several of these mCB-linked immune genes organized into coexpression networks that correlated with child anxiety and hyperactivity. Overall, our findings reveal a relationship between mCB and immune response gene networks in the placenta as a potential mediator of risk for anxiety-related problems in early childhood.

Peri-Pregnancy Cannabis Use and Autism Spectrum Disorder in the Offspring: Findings from the Study to Explore Early Development.

The association of autism spectrum disorder (ASD) with self-reported maternal cannabis use from 3months pre-conception to delivery ("peri-pregnancy") was assessed in children aged 30-68months, born 2003 to 2011. Children with ASD (N = 1428) were compared to children with other developmental delays/disorders (DD, N = 1198) and population controls (POP, N = 1628). Peri-pregnancy cannabis use was reported for 5.2% of ASD, 3.2% of DD and 4.4% of POP children. Adjusted odds of peri-pregnancy cannabis use did not differ significantly between ASD cases and DD or POP controls. Results were similar for any use during pregnancy. However, given potential risks suggested by underlying neurobiology and animal models, further studies in more recent cohorts, in which cannabis use and perception may have changed, are needed.

Foetal tobacco and cannabis exposure, body fat and cardio‐metabolic health in childhood

SummaryBackgroundFoetal tobacco and cannabis exposure may have persistent cardio‐metabolic consequences in the offspring.ObjectiveWe examined the associations of maternal and paternal tobacco and cannabis use during pregnancy with offspring body fat and cardio‐metabolic outcomes.MethodsIn a population‐based prospective cohort study among 4792 mothers, fathers, and children, we assessed parental substance use by questionnaires. Childhood outcomes included body mass index (BMI), body fat, blood pressure, and lipid, glucose and insulin concentrations at 10 years.ResultsChildren exposed to maternal tobacco use during pregnancy had a higher android/gynoid fat mass ratio (difference 0.22 SDS, 95% confidence interval [CI]: 0.13, 0.30), fat mass index (difference 0.20 SDS, 95% CI: 0.12, 0.28), triglyceride concentrations (difference 0.15 SDS, 95% CI: 0.04, 0.26), and a higher risk of overweight (odds ratio [OR] 1.35, 95% CI: 1.07, 1.71), compared to non‐exposed. Children exposed to maternal cannabis during pregnancy had a higher BMI (difference 0.26 SDS, 95% CI: 0.08, 0.44), android/gynoid fat mass ratio (difference 0.21 SDS, 95% CI: 0.04, 0.39), and fat‐free mass index (difference 0.24 SDS, 95% CI: 0.06, 0.41), compared to non‐exposed. The associations for paternal substance use with child cardio‐metabolic health outcomes were similar as those for maternal use.ConclusionsSimilar associations for maternal and paternal substance use during pregnancy suggest that these findings may be explained by shared family‐based social and lifestyle factors, rather than by direct foetal programming.

Prenatal cannabis use disorder and future risk of road traffic injuries in Canadian children

The extent to which child traffic injuries may be attributed to parents who use cannabis before driving is unknown. We investigated whether prenatal cannabis use disorders may predict future road traffic injuries in children. We conducted a cohort study of 792,082 children in Quebec, Canada with 6,280,663 years of follow-up between 2006 and 2019. The main exposure measure was maternal cannabis use disorder before or during pregnancy. The main outcome measure was future hospitalizations for transport-related injuries in children after birth. Using Cox proportional hazards regression models adjusted for potential confounders, we estimated hazard ratios and 95% confidence intervals (CI) for the association of prenatal cannabis use disorders with transport-related injuries in children. Maternal cannabis use disorders before birth were associated with 5.64 times the risk of hospitalization for future motor vehicle crash injuries in children (95% CI 2.61–12.21). The risk increased with the child's age. Prenatal cocaine, opioid, and other drug use disorders were not associated with pediatric transport-related injuries. Maternal cannabis use disorders before birth may be an early predictor of childhood injuries from motor vehicle crashes.

Maternal Cannabis Use in the Perinatal Period: Data From the Pregnancy Risk Assessment Monitoring System Marijuana Supplement, 2016-2018.

To estimate the prevalence of perinatal cannabis use (ie, before and/or during pregnancy); document the frequency, modes, and motivations for use; and identify predictors of perinatal cannabis use. Six states in the Pregnancy Risk Assessment Monitoring System, a state-specific, population-based surveillance system, administered a supplemental questionnaire on perinatal cannabis use in 2016-2018. Women with live births were surveyed 2-6 months postpartum about behaviors ≤ 3 months preconception and during pregnancy. Demographic, psychosocial, and behavioral characteristics were examined in relation to perinatal cannabis use using multinomial regression models. Those who: (1) never used cannabis, (2) only used in preconception period, and (3) used in both preconception and prenatal periods were compared. Among 6428 respondents, 379 (5.8%) used cannabis pre-conceptionally only and 466 (4.4%) used in both the preconception and prenatal periods. Among those using prenatally, most reported smoking as their single mode (87.1%), with the two most common reasons being stress (83.8%) and nausea/vomiting (79.2%). Marital status, race/ethnicity, socioeconomic status, parity, and cigarette and alcohol use were significantly associated with perinatal cannabis use. Single (vs partnered) women were more likely to use cannabis prenatally (odds ratio = 2.4, 95% confidence interval: 1.5, 3.9) and non-Hispanic Black (vs White) women were less likely to use prenatally (odds ratio = 0.4, 95% confidence interval: 0.2, 0.8). Using a population-based sample of US births in six states, several demographic, psychosocial, and behavioral characteristics were identified in relation to perinatal cannabis use. These data are valuable for counseling in prenatal care and investigations of health effects.

Lasting effects of prenatal exposure to Cannabis in the retina of the offspring: an experimental study in mice

BackgroundPrenatal exposure to Cannabis is a worldwide growing problem. Although retina is part of the central nervous system, the impact of maternal Cannabis use on the retinal development and its postnatal consequences remains unknown. As the prenatal period is potentially sensitive in the normal development of the retina, we hypothesized that recreational use of Cannabis during pregnancy may alter retina structure in the offspring. To test this, we developed a murine model that mimics human exposure in terms of dose and use.MethodsPregnant BalbC mice were exposed daily for 5 min to Cannabis smoke (0.2 g of Cannabis) or filtered air, from gestational day 5 to 18 (N = 10/group). After weaning period, pups were separated and examined weekly. On days 60, 120, 200, and 360 after birth, 10 pups from each group were randomly selected for Spectral Domain Optical Coherence Tomography (SD-OCT) analysis of the retina. All retina layers were measured and inner, outer, and total retina thickness were calculated. Other 37 mice from both groups were sacrificed on days 20, 60, and 360 for retinal stereology (total volume of the retina and volume fraction of each retinal layer) and light microscopy. Means and standard deviations were calculated and MANOVA was performed.ResultsThe retina of animals which mother was exposed to Cannabis during gestation was 17% thinner on day 120 (young adult) than controls (P = 0.003) due to 21% thinning of the outer retina (P = 0.001). The offspring of mice from the exposed group presented thickening of the IS/OS in comparison to controls on day 200 (P < 0.001). In the volumetric analyzes by retinal stereology, the exposed mice presented transitory increase of the IS/OS total volume and volume fraction on day 60 (young adult) compared to controls (P = 0.008 and P = 0.035, respectively). On light microscopy, exposed mice presented thickening of the IS/OS on day 360 (adult) compared to controls (P = 0.03).ConclusionGestational exposure to Cannabis smoke may cause structural changes in the retina of the offspring that return to normal on mice adulthood. These experimental evidences suggest that children and young adults whose mothers smoked Cannabis during pregnancy may require earlier and more frequent clinical care than the non-exposed population.

Parental cannabis and tobacco use during pregnancy and childhood hair cortisol concentrations

BackgroundFetal exposure to cannabis and tobacco during pregnancy leads to adverse fetal and childhood outcomes. We hypothesized that fetal exposure to cannabis and tobacco have persistent programming effects on hypothalamic pituitary adrenal (HPA) axis functioning in childhood. Therefore, we examined the associations of parental cannabis and tobacco use during pregnancy with childhood hair cortisol and cortisone concentrations at 6 years, as biomarkers of long-term HPA-axis functioning. MethodIn a population-based prospective birth cohort among 2577 mothers and their children, information of parental cannabis and tobacco use was collected by questionnaires, and maternal urine samples were additionally analyzed to detect cannabis metabolite concentrations. Cortisol and cortisone were measured in hair samples at 6 years. Linear regression analysis with adjustment for several confounders was used to test our hypothesis. ResultsAs compared to non-exposed children, offspring exposed to cannabis during pregnancy (in combination with tobacco) had higher childhood cortisol concentrations (log-10 transformed difference 0.16, 95 % Confidence Interval 0.04 to 0.28). This association was not mediated by birth weight. No differences in cortisone concentrations among cannabis-exposed children were observed. Maternal tobacco use during pregnancy was not associated with childhood cortisol or cortisone concentrations. Further, paternal cannabis or tobacco use was not associated with childhood cortisol or cortisone concentrations. ConclusionsOur findings suggest that maternal cannabis use, combined with tobacco, during pregnancy is associated with alterations in offspring HPA-axis functioning. Further studies need to replicate these findings, and assess the causality and long-term consequences of these associations.

The Impact of Cannabinoid Exposure on Glucocorticoid Receptor Signaling in Neural Stem Cells

Preterm birth-birth before 37 weeks of pregnancy-can cause many short- and long-term complications in newborns, including respiratory distress syndrome (RDS). RDS results from incomplete lung development and a surfactant deficiency, and it is a major factor of pre-term mortality. Synthetic glucocorticoids (sGCs) such as Betamethasone or Dexamethasone (Beta, Dex) are administered prenatally to women at risk of pre-term birth to prevent preterm complications. While sGCs are known to improve outcome, they also cause alterations in brain development and neural stem cell biology that are associated with long-term neurological defects.One common recreational drug used during pregnancy is cannabis. Some of the active components of cannabis include cannabinoids, which interact with the endocannabinoid receptor pathway in cells. Cannabinoids have been shown to induce proliferation and differentiation of embryonic neural stem cells (NSCs). We hypothesized that maternal cannabis use activates cannabinoid signaling pathways and leads to changes in glucocorticoid signaling in the developing brain. The purpose of this study was to determine whether cannabis use leads to a better or worse neurological outcome for children born pre-term and treated with sGCs for RDS.Neural stem cell neurospheres (NSCs) were isolated from the cerebral cortex of mice and treated with Vehicle (ethanol), Dex, cannabinoid receptor agonist WIN-55,212-2 (Win), or a combination WinDex. The transcriptional profile induced by exposure to Vehicle, Dex, and WinDex RNA were analyzed using microarray analyses examining the complete expressed genome. Gene Chip profiles indicated that both glucocorticoids and cannabinoids induce distinct transcriptional responses in E14.5 NSCs. The genes involved in proliferation-including S100a11, Jun, and Bex2-were repressed by Dex whereas WinDex rescued some of these expression profiles. Some genes encoding microRNA that inhibit our top target coding genes implicated in proliferation showed a greater induction by Dex compared to WinDex.Quantitative Polymerase Chain Reaction (qPCR) was performed to validate our genes of interest, including Adm, which has been shown to induce neural stem cell proliferation and differentiation. The biological impact of Winn on Dex-induced changes in NSC function were examined by in-vitro proliferation and differentiation studies using antibodies to Tuj1 (neurons), GFAP (glia), and CNPase (immature oligodendrocytes). The experiments indicate that Dex increased neuronal and oligodendrocyte differentiation, while WinDex appeared to reverse this phenotype in neurons.These studies suggest that cannabis use during pregnancy may limit the biological impact sGCs for preterm birth and lead to distinct cellular responses.

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

Recent studies have revealed increases in population-level cannabis use after legalization of recreational cannabis. However, the association of cannabis legalization with maternal cannabis use during important life stages remains unknown. To investigate the association of legalization of recreational cannabis with maternal cannabis use during the preconception, prenatal, and postpartum periods. This repeated cross-sectional study used state-level data on women who delivered live-born infants in the US from the Pregnancy Risk Assessment Monitoring System from January 2004 to December 2018. Data from 2 states that had legalized recreational cannabis (Alaska and Maine) and 2 states that had not legalized recreational cannabis (New Hampshire and Vermont) were used. Women completed surveys 2 to 6 months after delivery, reporting preconception, prenatal, and postpartum cannabis use. State recreational cannabis legalization. The 3 primary outcomes were self-reported cannabis use during the 12 months before pregnancy (preconception), during pregnancy (prenatal), and the 2 to 6 months after pregnancy (postpartum). A difference-in-differences analysis was used to compare changes in the prevalence of maternal cannabis use during each period before and after state legalization of recreational cannabis, controlling for maternal characteristics (age, race/ethnicity, educational level, income, cigarette smoking, and breastfeeding) and state fixed effects. State-specific survey weights were used. The analytic sample included 23 082 women in the preconception period, 23 859 in the prenatal period, and 26 610 in the postpartum period. In each analysis, most women were married (range among all groups, 63.9%-64.8%), aged 25 to 34 years (preconception, 55.4%; prenatal, 55.9%; postpartum, 56.1%), and had an annual household income less than $50 000 (preconception, 55.7%; prenatal, 56.3%; postpartum, 55.5%). In adjusted analyses, preconception and postpartum cannabis use increased significantly in states that had legalized recreational cannabis compared with states that had not legalized it (preconception risk difference, 0.0457 [95% CI, 0.0013-0.0900]; P = .04; postpartum risk difference, 0.0539 [95% CI, 0.0259-0.0818]; P < .001). The risk difference for prenatal cannabis use was not significant (0.0070; 95% CI, -0.0120 to 0.0260; P = .47). In this repeated cross-sectional study, recreational cannabis legalization was associated with changes in maternal cannabis use before and after pregnancy. The findings suggest that future studies should undertake an interdisciplinary approach to maximize benefit and application of findings to future public health, health care, and policy sectors.

Cannabis use and measurement of cannabinoids in plasma and breast milk of breastfeeding mothers.

Information on cannabinoids in breast milk and maternal cannabis use is limited. We quantified cannabinoids in plasma and breast milk of breastfeeding mothers and assessed cannabis use patterns. This is a prospective study at a university hospital in a state with legal medical and recreational cannabis. Breast milk and plasma samples along with survey data were collected from volunteers using cannabis in the last 48 h at 2 weeks and 2 months postpartum. Twenty subjects were enrolled. Median age (IQR) was 27 (24-34) years. Median (IQR) instances of cannabis use in the last 7 days were visit 1: 17 (6-29) and visit 2: 23 (15-45). Median (IQR) tetrahydrocannabinol (THC) concentrations were: plasma 3.7 ng/ml (0.8-56.8) and breast milk 27.5 ng/ml (0.8-190.5). Median (IQR) cannabidiol (CBD) concentrations were: plasma 0.6 ng/ml (0.5-6.4) and breast milk 1.2 ng/ml (0.5-17.0). Median (IQR) THC M/P: 7.0 (1.8-34.6) and CBD M/P: 2.6. Median breast milk THC concentration increased from visit 1 to visit 2 by 30.2 ng/ml (95% CI 3.05-69.3 ng/ml). THC and CBD accumulate in breast milk. Breastfeeding mothers used cannabis frequently and increased use in the early postpartum period. Research on the effects of infant exposure to cannabinoids in breast milk is urgently needed. Cannabis use is increasing in the general population and many nursing mothers use cannabis. THC has been previously detected in breast milk but little is known on how it concentrates relative to plasma. Data on cannabinoids other than THC, reasons for cannabis use, and patterns of use in breastfeeding women are also limited. We detected THC and CBD in breast milk. Both concentrate in breast milk relative to plasma. We showed that breastfeeding mothers increased cannabis use in the weeks after childbirth. Further research is needed to evaluate infant exposure to cannabinoids via breast milk and effects on infant health.

Association between maternal cannabis use and birth outcomes: an observational study

BackgroundAs cannabis consumption is increasing globally, including among pregnant women, there is a critical need to understand the effects of cannabis on fetal development and birth outcomes. We had two objectives: to determine 1) the factors associated with self-reported cannabis use in the pre/early-pregnancy period, and 2) whether cannabis use is associated with low birth weight, preterm birth, or small size for gestational age (GA) infants.MethodsMaternal questionnaire and birth outcome data was gathered from 2229 women and 1778 singleton infants in the Ontario Birth Study, a hospital-based prospective cohort study (2013–2019). Women self-reported cannabis use within 3 months of learning their pregnancy status. Multivariable linear and logistic regression was conducted to 1) identify factors associated with cannabis use, and 2) determine the associations between cannabis use with the selected birth outcomes.ResultsCannabis use increased in the cohort over time. Women who reported cannabis use (N = 216) were more likely to be younger and more likely to use alcohol, tobacco, and prescription pain medication, although most did not. These women had infants born at lower average birth weights and had 2.0 times the odds of being small for GA (95% confidence interval: 1.3, 3.3) after multivariable adjustment for socioeconomic factors and other substance use.ConclusionOur results suggest that women who use cannabis around the time of conception have higher odds of having infants that are small for gestational age. Targeted clinical messaging may be most applicable to women actively trying to conceive.

Maternal cannabis use in pregnancy and child neurodevelopmental outcomes.

Cannabis use in pregnancy has increased1,2, and many women continue to use it throughout pregnancy3. With the legalization of recreational cannabis in many jurisdictions, there is concern about potentially adverse childhood outcomes related to prenatal exposure4. Using the provincial birth registry containing information on cannabis use during pregnancy, we perform a retrospective analysis of all live births in Ontario, Canada, between 1 April 2007 and 31 March 2012. We link pregnancy and birth data to provincial health administrative databases to ascertain child neurodevelopmental outcomes. We use matching techniques to control for confounding and Cox proportional hazards regression models to examine associations between prenatal cannabis use and child neurodevelopment. We find an association between maternal cannabis use in pregnancy and the incidence of autism spectrum disorder in the offspring. The incidence of autism spectrum disorder diagnosis was 4.00 per 1,000 person-years among children with exposure compared to 2.42 among unexposed children, and the fully adjusted hazard ratio was 1.51 (95% confidence interval: 1.17-1.96) in the matched cohort. The incidence of intellectual disability and learning disorders was higher among offspring of mothers who use cannabis in pregnancy, although less statistically robust. We emphasize a cautious interpretation of these findings given the likelihood of residual confounding.

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

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

Recreational Cannabis Legalization in the US and Maternal Use during the Preconception, Prenatal, and Postpartum Periods.

In the United States (US), recreational cannabis use is on the rise. Since 2011, 11 states and the District of Columbia have legalized cannabis for adult recreational use. As additional states consider legalizing, there is an urgent need to assess associations between recreational cannabis legalization and maternal use in the preconception, prenatal, and postpartum periods—all critical windows for maternal and child health. Using cross-sectional data from the 2016 Pregnancy Risk Assessment Monitoring System, we assessed associations between state cannabis legalization and self-reported maternal cannabis use. Using logistic regression, we estimated the adjusted prevalence ratio (PR) of cannabis use during the preconception, prenatal, and postpartum period for women delivering a live-born infant in three states that had legalized recreational cannabis (Alaska, Colorado, and Washington) and three states that had not legalized (Maine, Michigan, and New Hampshire) by 2016. Our final sample size was 7258 women. We utilized 95% confidence intervals (CI) and a significance level of alpha = 0.05. After adjustment for potential confounders, women who resided in states with legalized recreational cannabis were significantly more likely to use cannabis during the preconception (PR 1.52; 95%CI ranging from 1.28–1.80; p < 0.001), prenatal (PR 2.21; 95% CI ranging from 1.67–2.94; p < 0.001), and postpartum (PR 1.73; 95%CI ranging from 1.30–2.30; p < 0.001) periods, compared to women who resided in states without legalized recreational cannabis. Although evidence about the effect of marijuana use during these periods is nascent, these findings show potential for increased incidence of child exposure to cannabis. Longitudinal research is needed to assess immediate and sustained impacts of maternal use before and after state legalization of recreational cannabis.