Cannabis, the Pregnant Woman and Her Child

Weeding Out the Myths

SC Jaques; A Kingsbury; P Henshcke; C Chomchai; S Clews; J Falconer; ME Abdel-Latif; JM Feller; JL Oei


J Perinatol. 2014;34(6):417-424. 

In This Article

Abstract and Introduction


To review and summarise the literature reporting on cannabis use within western communities with specific reference to patterns of use, the pharmacology of its major psychoactive compounds, including placental and fetal transfer, and the impact of maternal cannabis use on pregnancy, the newborn infant and the developing child. Review of published articles, governmental guidelines and data and book chapters. Although cannabis is one of the most widely used illegal drugs, there is limited data about the prevalence of cannabis use in pregnant women, and it is likely that reported rates of exposure are significantly underestimated. With much of the available literature focusing on the impact of other illicit drugs such as opioids and stimulants, the effects of cannabis use in pregnancy on the developing fetus remain uncertain. Current evidence indicates that cannabis use both during pregnancy and lactation, may adversely affect neurodevelopment, especially during periods of critical brain growth both in the developing fetal brain and during adolescent maturation, with impacts on neuropsychiatric, behavioural and executive functioning. These reported effects may influence future adult productivity and lifetime outcomes. Despite the widespread use of cannabis by young women, there is limited information available about the impact perinatal cannabis use on the developing fetus and child, particularly the effects of cannabis use while breast feeding. Women who are using cannabis while pregnant and breast feeding should be advised of what is known about the potential adverse effects on fetal growth and development and encouraged to either stop using or decrease their use. Long-term follow-up of exposed children is crucial as neurocognitive and behavioural problems may benefit from early intervention aimed to reduce future problems such as delinquency, depression and substance use.


About 3.9% (or 180.6 million) of the world's population between 15 and 64 years of age use cannabis, making it one of the most widely used illegal psychoactive drugs in the world.[1] In some countries, cannabis has been used by up to 40% of adults at some point during their lives.[2] Cannabis is accepted as a relatively harmless recreational agent in many parts of the world[3] despite gathering evidence of its detrimental impact on both the adult[4] and the developing[5] central nervous system. Severe cannabis use, for example, decreases the metabolism of the prefrontal and temporal cortex,[63] and chronic exposure doubles the risk of psychosis and memory and cognitive dysfunction, most likely from neurotransmitter dysregulation.[7] This risk of neurological impairment is especially pronounced if cannabis is consumed during periods of critical brain development, such as adolescence.[8]

Cannabis, however, is one of the most commonly used illicit drugs in pregnancy and lactation.[1,2] Approximately 2.5% of women admit to continued cannabis use even during pregnancy.[9] This is of great concern because its lipophilic nature[10] allows it to readily cross many types of cell barriers, including the blood/brain and transplacental membranes. Cannabis metabolites are consequently easily detectable in many types of human tissues,[11] including the placenta, amniotic fluid and the fetus.[12] The effects of cannabis on the developing fetus may, however, be subtle and not be detectable for many months to years after birth, as the aetiology of some of the 'softer' neurological signs such as aggressive behaviours[5] or other neuropsychological problems[13] are difficult to be attributed unequivocally to cannabis exposure due to frequently concurrent negative environmental influences such as parental drug use, poverty[14] and psychiatric co-morbidity.[15]

Evidence regarding the effects of perinatal cannabis exposure, that is, during pregnancy and lactation, is plentiful but, unfortunately, ambiguous. In this review, we offer an overview of this problem, including discussion about the potential effects of this practice on the unborn, newborn and older child and adolescent. We also discuss some of the pertinent issues associated with perinatal management, including the utility of drug screening and the practical aspects of breast-feeding in the known cannabis user. Our overall aim is to provide the health practitioner with some guidance for advising women who use cannabis in pregnancy, including best available information on the potential effects of cannabis use on their unborn baby and future childhood development.