Prenatal Marijuana Exposure Research Articles

The Risk of Ventricular Septal Defects Associated With Prenatal Marijuana Exposure: A Systematic Review and Meta-Analysis.

With the recent legalization of marijuana across the United States, its usage in pregnant women has increased. The aim of this meta-analysis was to determine if prenatal marijuana use increases the likelihood of ventricular septal defects. The analysis was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The search strategy identified 4 case-control studies that were ultimately included in the analysis with a combined 381,621 infant records. Quantitative analysis demonstrated prenatal marijuana usage significantly increases the likelihood of ventricular septal defects (odds ratio = 2.39, 95% confidence interval = 1.11-5.18).

Impact of prenatal marijuana exposure on adolescent brain structural and functional connectivity and behavioural outcomes.

There has been an increase in the number of women using marijuana whilst pregnant. Previous studies have shown that children with prenatal marijuana exposure have developmental deficits in memory and decreased attentiveness. In this study, we assess whether prenatal marijuana exposure is associated with alterations in brain regional morphometry and functional and structural connectivity in adolescents. We downloaded behavioural scores and subject image files from the Adolescent Brain Cognitive DevelopmentSM Study. A total of 178 anatomical and diffusion magnetic resonance imaging files (88 prenatal marijuana exposure and 90 age- and gender-matched controls) and 152 resting-state functional magnetic resonance imaging files (76 prenatal marijuana exposure and 76 controls) were obtained. Behavioural metrics based on the parent-reported child behavioural checklist were also obtained for each subject. The associations of prenatal marijuana exposure with 17 subscales of the child behavioural checklist were calculated. We assessed differences in brain morphometry based on voxel-based and surface-based morphometry in adolescents with prenatal marijuana exposure versus controls. We also evaluated group differences in structural and functional connectivity in adolescents for region-to-region connectivity and graph theoretical metrics. Interactions of prenatal marijuana exposure and graph networks were assessed for impact on behavioural scores. Multiple comparison correction was performed as appropriate. Adolescents with prenatal marijuana exposure had greater abnormal or borderline child behavioural checklist scores in 9 out of 17 subscales. There were no significant differences in voxel- or surface-based morphometry, structural connectivity or functional connectivity between prenatal marijuana exposure and controls. However, there were significant differences in prenatal marijuana exposure-graph network interactions with respect to behavioural scores. There were three structural prenatal marijuana exposure-graph network interactions and seven functional prenatal marijuana exposure-graph network interactions that were significantly associated with behavioural scores. Whilst this study was not able to confirm anatomical or functional differences between prenatal marijuana exposure and unexposed pre-adolescent children, there were prenatal marijuana exposure-brain structural and functional graph network interactions that were significantly associated with behavioural scores. This suggests that altered brain networks may underlie behavioural outcomes in adolescents with prenatal marijuana exposure. More work needs to be conducted to better understand the prognostic value of brain structural and functional network measures in prenatal marijuana exposure.

Up in Smoke: The Impacts of Marijuana During Pregnancy.

Numerous drugs ingested during pregnancy can impact the developing fetus. Although some effects are apparent at birth as overt teratogenicity or profound neonatal withdrawal, others become apparent only after a careful long-term follow-up into childhood. Shifting legal and cultural attitudes toward marijuana have led to increased use during pregnancy. This shift should prompt health care providers to carefully consider the drug's mechanism of action, its interaction with the placenta, and the potential consequences of fetal exposure. The primary psychoactive compound in marijuana is Δ9-tetrahydrocannabinol (THC), which agonizes endogenous cannabinoid receptors. Cannabinoid receptors are present in the fetal brain early in gestation and appear to have an important role in the developing central nervous system. THC crosses the placenta in sufficient quantities to raise concerns about exogenous exposure during fetal development. Robust follow-up studies suggest that marijuana use during pregnancy contributes to suboptimal fetal growth. At school age, heavy prenatal marijuana exposure predicts challenges in executive function (specifically, memory and reasoning) and externalizing behavior (e.g., hyperactivity and inattention). Memory and behavioral problems persist into early adulthood. These challenges coincide with a higher risk of heavy marijuana use in offspring. In concert with a suboptimal environment, young adults may experience a higher risk of global cognitive impairment and/or delinquency. Importantly, these adverse outcomes appear to be mitigated by postnatal factors including home environment. Ongoing studies in the modern era will be vital to enhance our understanding of the mechanisms by which THC impacts the fetus and confirm or refute knowledge regarding long-term impact. This knowledge will inform both health care providers and parents in collaborative decision-making to optimize the outcome of children.

Neurodevelopmental outcomes in children after prenatal marijuana exposure.

The effect of prenatal marijuana exposure (PME) on child neurodevelopment remains poorly understood. Prior studies have demonstrated inconsistent results. This study evaluated the association between PME and neuropsychological test scores in late childhood and early adulthood, accounting for a wide range of parental characteristics. This study evaluated participants from the Raine Study, a cohort of 2868 children born between 1989 and 1992. Children whose mothers provided information on marijuana use during pregnancy were included. The primary outcome was the Clinical Evaluation of Language Fundamentals (CELF) at age 10. Secondary outcomes included the Peabody Picture Vocabulary Test (PPVT), Child Behaviour Checklist (CBCL), McCarron Assessment of Neuromuscular Development (MAND), Coloured Progressive Matrices (CPM), Symbol Digit Modality Test (SDMT) and Autism Spectrum Quotient (AQ) scores. Exposed and unexposed children were matched by propensity score using optimal full matching. Missing covariate data were imputed using multiple imputation. Inverse probability of censoring weighting (IPCW) was used to adjust for missing outcome data. Linear regression within matched sets, adjusted by IPCW, evaluated score differences between exposed and unexposed children. As a secondary analysis, modified Poisson regression, adjusted by match weights and IPCW, evaluated the risk of clinical deficit in each outcome following PME. Of the 2804 children in this cohort, 285 (10.2%) had PME. After optimal full matching and IPCW, exposed children scored similarly on CELF Total (-0.33 points, 95% confidence interval [CI] -4.71, 4.05), Receptive (+0.65 points, 95% CI -4.08, 5.38) or Expressive (-0.53 points, 95% CI -5.07, 4.02). PME was not associated with secondary outcomes or risks of clinical deficit in any neuropsychological assessments. After adjusting for sociodemographic and clinical covariates, PME was not associated with worse neuropsychological test scores at age 10 or autistic traits at 19-20.

Prenatal marijuana exposure and visual perception in toddlers: Evidence of a sensory processing deficit.

Research has identified a link between prenatal marijuana exposure and multiple outcomes in children, including cognitive development. Several studies have found specific differences in sensory processing and attention, with visual perception especially impacted in school age children. The current study explored whether this effect is evident at an earlier age, and thus our goal was to investigate the relationship between in-utero marijuana exposure and sensory processing capabilities in toddlers. We hypothesized that in-utero marijuana exposure throughout pregnancy would specifically predict visual sensory hyperactivity in children as young as 15 months of age. Participants were 225 15-month-old children whose mothers were recruited during pregnancy. Substance exposure was prospectively collected and biochemically verified, with marijuana coded as no exposure, 1st trimester exposure only, or exposure throughout pregnancy. The Infant Toddler Sensory Profile evaluated 5 domains of sensory processing (visual, auditory, tactile, vestibular, oral). Prenatal marijuana exposure throughout pregnancy, but not when limited to the first trimester, predicted a two-fold increased likelihood of scoring in a range indicating high levels of seeking out and potentially over-attending to visual stimulation after controlling for potentially confounding factors including other prenatal exposures. Marijuana exposure was not significantly related to other processing domains. Results indicate that links previously identified between prenatal marijuana exposure and visual function and attention may already be evident at 15 months of age, and also suggest an impact related to continuous/later pregnancy exposure. Our findings, as well as those from previous studies, all suggest visual processing differences for exposed children, differences that may predict emerging issues with visual attention and habituation. As legalization of marijuana continues to increase, further research is clearly needed to examine specific teratologic effects associated with use during pregnancy.

Altered White Matter Connectivity in Children with Prenatal Marijuana Exposure


 
 
 Background:
 The potential health outcomes of cannabis use during pregnancy are currently not well-known. Several studies have shown an association between prenatal marijuana exposure (PME) and adverse neonatal outcomes. Specifically, cannabis use has been associated with an increased risk of cognitive deficits and neuropsychiatric disease. The aim of this project is to examine alterations in cerebral white matter connectivity of children with PME compared to unexposed controls based on diffusion tensor imaging (DTI). Identifying such microstructural alterations may help us better understand neurodevelopmental and cognitive effects of PME.
 Hypothesis:
 We hypothesize that there will be differences in white matter connectivity in children with PME compared to controls.
 Methods:
 DTI images for children with (n=88) and without (n=90) PME were obtained from the Adolescent Brain Cognitive Development (ABCD) Study database. Image quality assurance, preprocessing, and tractography were completed using DSI Studio. Fiber counts between 94 regions of interest were assessed. A groupwise comparison was performed to assess differences in structural connectivity in children with and without PME.
 Results:
 The PME group and control group had 35 and 37 males, respectively. The mean age for both groups was 9.9 years. First level comparative analysis revealed alterations in microstructural connectivity between PME and control groups. Increased connectivity was found in the PME group compared to the control group in 51 tracts, while decreased connectivity was indicated in 22 tracts. However, significance was not maintained when corrected for multiple comparisons.
 Conclusion/Impact:
 Although there were small alterations in brain structural connectivity in children with PME, these were not significant after correcting for multiple comparisons. It is possible that microstructural neuroplasticity in the developing brain lowers the impact of potential long-term adverse effects of marijuana exposure in utero. Further studies are required to understand longitudinal brain development and adverse neurodevelopmental and cognitive outcomes associated with PME.
 
 

Prenatal marijuana exposure and neonatal outcomes: a retrospective cohort study

ObjectivesPrevious 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...

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

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. 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. 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). 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. · 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..

Animal Models Evaluating the Impact of Prenatal Exposure to Tobacco and Marijuana.

Within this review, the literature and outcomes from animal models of maternal marijuana use and cigarette smoking are summarized. The existing data demonstrate that prenatal marijuana and nicotine exposure both have multifaceted adverse effects on maternal, gestational, placental, and fetal outcomes. These include placental function and development, fetal growth and birth weight, and offspring neurodevelopment.

Implementation of the North Carolina Plan of Safe Care in Wake County, North Carolina.

BACKGROUND The Comprehensive Addiction and Recovery Act (CARA) of 2016 amended the Child Abuse Prevention and Treatment Act (CAPTA), reinforcing and revising the requirement that states develop policies and procedures to address the needs of substance-affected infants and their caregivers. North Carolina's program, the North Carolina Plan of Safe Care (NC POSC), was implemented in August 2017 and involves coordination between multiple agencies.METHODS We conducted a quality improvement project to assess implementation of the North Carolina Plan of Safe Care in Wake County through interviews with key stakeholders involved in program delivery including health care providers (n = 7), child protective services social workers (CPS; n = 14), and care managers at Care Coordination for Children (CC4C; n = 10). We also analyzed data on Plan of Safe Care notifications to Wake County CPS from January 2018 to October 2019.RESULTS Several key themes emerged in stakeholder interviews, including 1) lack of awareness of the program among health care providers; 2) gaps in information sharing and communication between agencies; 3) concerns regarding CPS notifications for all substance exposure types, including prenatal exposure to medication for opioid use disorder (MOUD); 4) common family needs and service referrals; 5) challenges engaging with families; 6) lack of knowledge among health care providers and CPS social workers regarding CC4C; and 7) benefits of the program for infants and families. From January 2018 to October 2019, 91% of notifications for substance-affected infants received by Wake County CPS as part of the NC POSC were screened-in for a maltreatment assessment. Of those screened-in, more than two-thirds (70%) involved prenatal marijuana exposure only.LIMITATIONS This project was limited to one county.CONCLUSIONS As NC POSC implementation continues, further consideration of the infrastructure and guidance available to address the implementation challenges identified by stakeholders will be essential to meeting family needs and promoting infant safety and well-being.

Behavioral and cognitive differences in early childhood related to prenatal marijuana exposure

Prenatal marijuana exposure (PME) negatively impacts child development and behavior; however, few studies have examined these associations at early ages among children exposed to today's highly potent marijuana. Using a prospective prenatal cohort (Columbus, Ohio, USA), PME was determined from maternal self-report, medical chart abstraction, and urine toxicology from prenatal visits and delivery. At age 3.5 years, 63 offspring children completed tasks assessing executive function (EF), visual spatial ability, emotion regulation, and aggressive behavior. Caregivers reported on children's EF and problem behaviors. Logistic regressions and analyses of covariance controlling for key variables were used to examine associations between PME and child outcomes. Compared to non-exposed children, children with PME had more sleep-related problems, withdrawal symptoms, and externalizing problems, including aggressive behaviors and oppositional defiant behaviors. Children with and without PME did not differ in terms of executive functioning. Findings suggest behavioral problems associated with PME may manifest by age 3.5.

Effects of marijuana on reproductive health: preconception and gestational effects.

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. 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. 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.

Marijuana use and sleep quality during pregnancy

Objective Marijuana use among pregnant women is on the rise in part due to the perception that marijuana may improve problems related to pregnancy such as poor sleep. This study’s objective was to examine associations between marijuana use and sleep quality among a sample of women during pregnancy. Material and methods The sample included women seeking prenatal care at The Ohio State University Wexner Medical Center (2010–2015). Intake assessments included medical, demographic, and socioeconomic domains, as well as the Pittsburgh Sleep Quality Index. Marijuana use during pregnancy was determined using urine screens, chart abstraction, and self-report. Women completed standardized questionnaires regarding sleep quality, depressive symptoms, anxiety, stress, and discrimination at enrollment and each subsequent trimester. A linear mixed-effect model was used to assess the relationship between sleep variables and marijuana use adjusted for maternal race, education, household income, age, marital status, depressive symptoms, anxiety, stress, discrimination, and use of tobacco and other substances during pregnancy. Women completed the sleep quality assessments for a total of 294 pregnancies, which comprise the study population. Results Among the study sample (n = 294), 93 women used marijuana and 201 women did not use marijuana during their pregnancies. Women who used marijuana (n = 93) were more likely to identify as African-American (73% vs 58%; p = .01), report government health insurance (98% vs 89%; p = .001), use tobacco during pregnancy (66% vs 33%; p < .001), report less household income (70% vs 43% < 10,000 annual household income; p < .001), and be unmarried (69% vs 49%; p < .001) compared to women who did not. Mean sleep quality was similar among women who did (µ = 7.6; SD = 4.0) and did not use marijuana during pregnancy (µ = 7.7; SD = 4.0), and both groups had a mean score worse than the conventional cutoff for poor sleep quality (>5). In fact, both groups reported worse sleep than is typically observed among cohorts reporting poor sleep, which have ranged from 5.3 to 6.3. Conclusions Current findings did not suggest differences in sleep quality between women who used and did not use marijuana during pregnancy. Findings are contrary to the perception that marijuana use alleviates sleep-related problems during pregnancy. Given well-documented adverse outcomes associated with prenatal marijuana exposure for children and the increase in women using marijuana during pregnancy, providers should be prepared to discuss possible harms associated with marijuana use during pregnancy as well as provide psychoeducational information and service referrals to those interested. Future studies could improve upon this design by assessing objective measures of sleep, such as actigraphy, as well as marijuana use repeatedly throughout pregnancy, which may be a more optimal strategy for illuminating potential relationships between marijuana use and sleep during pregnancy.

Imaging Epigenetics of Prenatal THC.

Prenatal exposure to marijuana may lead to epigenetic alterations in the placenta and fetal brain, affecting short- and long-term offspring health. This Viewpoint addresses the critical need to study and characterize the impact of maternal marijuana use and consequences of in utero exposure on later development and health. We highlight the development of new PET imaging tools and the opportunity for longitudinal in vivo non-human primate studies to help elucidate epigenetic changes resulting from prenatal marijuana exposure throughout gestation.

55 Early prenatal marijuana and nicotine exposure and child neurodevelopmental outcomes

55 Early prenatal marijuana and nicotine exposure and child neurodevelopmental outcomes

A longitudinal study of the impact of marijuana on adult memory function: Prenatal, adolescent, and young adult exposures

More Americans are using marijuana than in previous decades but there are concerns over its long-term impact on cognitive functioning, especially memory. The literature on marijuana use and cognitive functioning is mixed, with some studies showing recovery of functioning upon abstinence from the drug and others showing long-term effects that persist. The latter seems especially true for individuals who initiate marijuana at a younger age and engage in more chronic patterns of use. The goal of the current study is to use prospectively collected data on young adults from a prenatal cohort to determine if there is an effect of early and/or current marijuana use on young adult memory, controlling for prenatal exposure to marijuana use, childhood memory deficits, and other significant covariates of memory functioning. At the 22-year follow-up phase of the Maternal Health Practices and Child Development (MHPCD) study, 524 young adults (58% Black, 42% White, 52% female) completed the Wechsler Memory Scale-III. Multiple regression analyses and structural equation modeling were used to determine the effect of marijuana exposure during gestation, early adolescence, and young adulthood on young adult memory function. Results indicated that initiating marijuana use before age 15 placed young adults at greater risk of memory deficits, even after controlling for childhood memory and current marijuana use. First trimester marijuana exposure also indirectly predicted young adult memory function via childhood memory deficits and early initiation of marijuana. These findings highlight the risk of prenatal marijuana exposure and early initiation of marijuana for long-term memory function in adulthood.

Lifestyle and Early Achievement in Families (LEAF) study: Design of an ambidirectional cohort study of prenatal marijuana exposure and child development and behaviour.

Marijuana is the most-used illicit substance during pregnancy in the USA, but only two cohort studies, begun over 30years ago, were specifically established to assess the association of pregnancy use with childhood outcomes. They found use to be associated with specific deficits in executive function at 8+years, but did not focus on these outcomes earlier in life when intervention may be more successful. Two general purpose cohorts found increased aggression in exposed female toddlers and increased behavioural problems and tic disorders in exposed school-age children. The Lifestyle and Early Achievement in Families (LEAF) study assesses the association of in utero marijuana exposure, documented prospectively by biomarker, self-report, and medical records, with executive function and aggression at age 3½-7years. This ambidirectional cohort (historical cohort with continued follow-up) includes women enrolled in the Perinatal Research Repository during prenatal care at Ohio State University Wexner Medical Center and their children, recontacted 3½-7years post-birth. Children complete 1-2 study visits including cognitive testing, behavioural observation, and maternal and teacher report of behaviour. Family and social environmental factors are assessed. Child follow-up began in September 2016; visits continue through August 2020. There are 362 eligible children; 32% had mothers who used marijuana during pregnancy, 10% of mothers completed college, and 23% did not complete high school. Mean maternal age at study registration in pregnancy was 26.4years, and 63% of mothers were African American. To date, 268 children have completed at least 1 study visit. The LEAF Study will document the association of prenatal marijuana exposure with development and behaviour in the current era when marijuana is more potent than when previous cohorts were studied. The results may inform policy and interventions to counsel reproductive-aged women about the risks of use during pregnancy and guide prevention and treatment of adverse effects among children.

The Effects of Prenatal Exposure to Marijuana on Early Childhood Development: A Systematic Literature Review

To assess the effect of prenatal marijuana exposure (PME) on the newborn, infant and early childhood development through review of current literature. A systematic literature review was conducted in the electronic database from 1996 to 2017 for the effects of PME and their fetal and early childhood outcomes. 7% of pregnant women self-reported using marijuana in the last year, while 16% of them reported near-daily use. Marijuana use has been reported to: a) interfere with normal placentation leading to miscarriage, preeclampsia and preterm labor through imbalance in Cannabinoid receptor type 1 (CBR1) stimulation; b) could lead to reduction of fetal growth and head circumference due to increased plasticity and resistance of uterine artery; c) be associated with impaired memory function, decreased verbal scores, increased aggression and hyperactivity, impaired abstract and visual reasoning; and d) could alter sleep patterns. Finally, there is no consensus regarding the effects of marijuana through breastfeeding exposure and no postpartum withdrawal effects in the newborn were reported. Research on the effects of PME on offspring has been limited by several confounding factors including self-reporting bias, concomitant use of other illicit drugs and psychosocial factors. Overall, PME may lead to negative consequences on the developing offspring. Public health messages to health care providers and pregnant women regarding the harmfulness of PME should become a high priority. Further research is needed to reinforce the existing data and examine additional potential negative effects on the developing child.

Is the Use of Cannabis during Pregnancy a Risk Factor for Autism?

The use of marijuana by healthy adults is commonly viewed as having limited adverse health effects; however, its potential risks for fetal developmental abnormalities when used during pregnancy have not been thoroughly evaluated. Marijuana is known to bind to endogenous cannabinoid receptors and exert physiological effects similar to endogenous cannabinoids. The endocannabinoid system is involved in cognition, behavioral, and emotional regulation. Autism Spectrum Disorder is associated with mild to severe cognitive, social and behavioral impairments; moreover, impairments in the endocannabinoid system have been identified in individuals with this disorder. It is, therefore, possible that marijuana use during pregnancy may cause the overexcitation of the endocannabinoid system during early brain development to make the fetus at risk for autism spectrum disorder. The present study aims to explore the effects of prenatal marijuana exposure on the endocannabinoid system, and to present a model of how this interaction may increase risk of developing autism spectrum disorder.

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.