Physical Effects

Marijuana and the Risks to Pregnancy & Breastfeeding

Marijuana contains almost 500 components including the psychoactive ingredient THC that can pass through the placenta to the baby during pregnancy, causing harm to the fetus.
Marijuana use by a breastfeeding mother can expose the newborn to toxins stored in the mother’s fat tissues and slowly released to baby, even after the mother has stopped using.
Learn about the various risks of using marijuana during pregnancy and while breastfeeding through the resources below.

Cannabis can cross the placental and blood-brain barriers and is excreted in breast milk. The scope is wider than pregnancy alone as it accumulates and is active for many weeks. 

Conclusions and relevance: This study suggests that prenatal cannabis exposure and its correlated factors are associated with greater risk for psychopathology during middle childhood. Cannabis use during pregnancy should be discouraged.     

Research has found that prenatal cannabis use may adversely affect fetal growth and neurodevelopment, be associated with future learning and behavioral problems in children, and increase risk of neonatal morbidity. (Cornelius et al., 2002; Day et al., 1994; El Marroun et al., 2011; Fried and Smith, 2001; Fried et al., 1999; Fried et al., 2003; Fried et al., 1997; Goldschmidt et al., 2000; Goldschmidt et al., 2008; Goldschmidt et al., 2012; Metz et al., 2017; Noland et al., 2005; Willford et al., 2010; Ryan et al., 2018; El Marroun et al., 2018) Several US organizations, including the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics, recommend abstinence from cannabis use during pregnancy. (Ryan et al., 2018; Gynecologists, T.A.C.O.O.A, 2020) Despite these recommendations, there are concerns that the trend of cannabis use during pregnancy will continue to increase as more states and countries legalize cannabis and allow for commercial sales through dispensaries. (Mark and Terplan, 2017)

Results
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 NICU admission, and had lower birth weight, head circumference, and birth length than infants of mothers not reporting cannabis use. These associations did not differ before and after legalisation.

Conclusions
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 five years in Nova Scotia with no apparent additional effect of legalisation.

In human studies, the preponderance of evidence suggests that prenatal cannabinoid exposure is predictive of several adverse neonatal outcomes, most notably FGR Fetal growth restriction and LBW low birth weight.
There is thus an urgent need to better understand the mechanistic links between these prenatal developmental events, their impact upon neurodevelopmental pathology and risk factors and how exposure to cannabinoids might synergistically modulate these complex interrelationships.
 

Maternal cannabis use in pregnancy and child neurodevelopmental outcomes 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. 
 

Marijuana Use During Pregnancy Linked To Autism In Children: Study
 

Very scientific and medical article.
Early detection and alerting pregnant women about the risks of cannabis use during pregnancy is one way to minimize its possible harm. ..An active involvement is required from primary care, obstetricians, pediatric, mental health and drug dependence services

What Do I Need to Know about Marijuana?   Podcasts   Answers all the myths with science and facts.  Is it safe to drive using marijuana?  If it is a medicine, how can it hurt me?  What does marijuana use do to my brain? ....

Cannabis effects on fetal growth (eg, low birth weight and length) may be more pronounced in women who consume marijuana frequently, especially in the first and second trimesters.4 This study highlights the importance of screening and interventions for cannabis use among all pregnant women. 
This study highlights the importance of screening and interventions for cannabis use among all pregnant women.

Significant effects of prenatal cannabis exposure have been found on children's sleep, cognitive functions (memory and scholastic skills), as well as on executive (frontal lobe) functions (reasoning, attention, impulsivity, and motivation), and affective (depression) and anxiety symptoms throughout the stages of development. Following the presentation of two case vignettes, we integrate the published information on outcomes of maternal use of cannabis during pregnancy on the developing fetus and the "soft" neurological deficits and neuro-behavioral disturbances manifested by them from early childhood and evolving to peaks in adolescence. Taken together, these data serve to define what we call a heretofore unspecified "fetal cannabis spectrum disorder".

Large-scale, longitudinal studies of humans whose mothers smoked marijuana once or more per week and experimental work on rodents exposed to cannabinoids in utero have yielded remarkably consistent intellectual and behavioral correlates of fetal exposure to this drug. Some exposed individuals exhibit deficits in memory, cognition, and measures of sociability. These aberrations appear during infancy and persist through adulthood and are tied to changes in the expression of multiple gene families, as well as more global measures of brain responsiveness and plasticity. Researchers currently consider these perturbations to be mediated by changes to the endocannabinoid system caused by the active compounds in cannabis. 

The importance of the published findings and the emerging research regarding the potential negative effects of marijuana on brain development are a cause for concern despite the limited research and are the basis for the following recommendations:

1. Women who are considering becoming pregnant or who are of reproductive age need to be informed about the lack of definitive research and counseled about the current concerns regarding potential adverse effects of THC use on the woman and on fetal, infant, and child development. Marijuana can be included as part of a discussion about the use of tobacco, alcohol, and other drugs and medications during pregnancy.
2. As part of routine anticipatory guidance and in addition to contraception counseling, it is important to advise all adolescents and young women that if they become pregnant, marijuana should not be used during pregnancy.
3. Pregnant women who are using marijuana or other cannabinoid-containing products to treat a medical condition or to treat nausea and vomiting during pregnancy should be counseled about the lack of safety data and the possible adverse effects of THC in these products on the developing fetus and referred to their health care provider for alternative treatments that have better pregnancy-specific safety data.
4. Women of reproductive age who are pregnant or planning to become pregnant and are identified through universal screening as using marijuana should be counseled and, as clinically indicated, receive brief intervention and be referred to treatment.
5. Although marijuana is legal in some states, pregnant women who use marijuana can be subject to child welfare investigations if they have a positive marijuana screen result. Health care providers should emphasize that the purpose of screening is to allow treatment of the woman’s substance use, not to punish or prosecute her.
6. Present data are insufficient to assess the effects of exposure of infants to maternal marijuana use during breastfeeding. As a result, maternal marijuana use while breastfeeding is discouraged. Because the potential risks of infant exposure to marijuana metabolites are unknown, women should be informed of the potential risk of exposure during lactation and encouraged to abstain from using any marijuana products while breastfeeding.
7. Pregnant or breastfeeding women should be cautioned about infant exposure to smoke from marijuana in the environment, given emerging data on the effects of passive marijuana smoke.
8. Women who have become abstinent from previous marijuana use should be encouraged to remain abstinent while pregnant and breastfeeding.
9. Further research regarding the use of and effects of marijuana during pregnancy and breastfeeding is needed.
10. Pediatricians are urged to work with their state and/or local health departments if legalization of marijuana is being considered or has occurred in their state to help with constructive, nonpunitive policy and education for families.

They also discovered that prenatal marijuana use was associated with a 50 percent increased chance of low birth weight regardless of tobacco use during pregnancy. “Growing evidence suggests prenatal cannabis exposure has a detrimental impact on offspring brain function starting in the toddler years, specifically issues related to attention deficit disorder,” Crume said. “But much of the research on the effects of prenatal cannabis on neonatal outcomes was based on marijuana exposures in the 1980s and 1990s which may not reflect the potency of today’s cannabis or the many ways it is used.”

Even after less than six years of smoking the drug, the ill effects were already being seen on their breathing, according the research presented at the British Thoracic Society (BTS) winter meeting.
 
"It is vital that young people understand the dangers of both cigarette and cannabis smoking since these habits can start having a serious impact on their lungs at an early stage."