Guidelines and Risks of Cannabis Use During Pregnancy and Breastfeeding
Women who are pregnant, trying to become pregnant, or breastfeeding should completely abstain from using cannabis due to established risks of adverse fetal and neonatal outcomes. 1
Established Risks of Cannabis Use During Pregnancy
Fetal Development Risks
- Cannabis smoking during pregnancy is associated with low birthweight 1
- Delta-9-tetrahydrocannabinol (THC) readily crosses the placenta 2
- Cannabinoid receptors have been identified in fetal brain and placenta, making the developing fetus vulnerable to cannabis exposure 2
- Potential developmental disruption including increased risk of fetal growth restriction 2
Maternal Risks
- Inaccurate product labeling of THC concentration levels is common, making dosing unpredictable 1
- Many cannabis products have not been evaluated or approved for safe use and may be marketed in ways that put public health at risk 1
Postnatal Risks
Breastfeeding Concerns
- Cannabis passes into breast milk, resulting in neonatal exposure 3
- Breastfeeding is contraindicated with concurrent use of illicit substances, including cannabis 1
- Insufficient data exists to evaluate the effects of marijuana use on infants during lactation 4
Neurodevelopmental Outcomes
- In utero exposure to cannabis has been associated with adverse neurodevelopmental consequences that persist into young adulthood 5, 2
- Three longitudinal cohort studies demonstrate possible effects of prenatal marijuana exposure on long-term neurobehavioral outcomes 3
Medical Use Considerations
Pregnancy-Related Symptoms
- Despite some women citing medical reasons for prenatal marijuana use (such as nausea and vomiting of pregnancy, anxiety, and chronic pain), cannabis should not be used to treat these conditions during pregnancy 3, 5
- Chronic cannabis use might lead to the development of cannabinoid hyperemesis syndrome 5
- Women should be encouraged to discontinue marijuana use for medicinal purposes in favor of alternative therapies with better pregnancy-specific safety data 4
Clinical Approach to Cannabis Use in Pregnancy and Breastfeeding
Screening and Counseling
- Healthcare providers should inform pregnant patients about the known and potential dangers of cannabis use during pregnancy 1
- Dispel misleading claims about the safety of cannabis use during pregnancy 1
- Discuss the absence of safety data and long-term follow-up data on cannabis-exposed pregnancies and infants 6
Recommendations for Practice
- If complete abstinence is not feasible, reduction of use as much as possible is recommended 6
- For women who continue to use cannabis, education about harm reduction is important 1
- Anticipatory guidance should include education about potential involvement of social services after delivery (based on local laws) 1
Common Pitfalls in Management
- Failure to recognize that there is no known safe level of cannabis use during pregnancy or lactation 5
- Underestimating exposure due to reliance on self-reporting 3
- Not addressing confounding factors such as tobacco use and sociodemographic differences when evaluating risks 3
- Assuming that legalization of cannabis implies safety during pregnancy and breastfeeding 4
- Not recognizing that THC concentrations in cannabis products have almost doubled from 9% in 2008 to 17% in 2017, making older research potentially less applicable to current products 7
In conclusion, the most current evidence strongly supports complete abstinence from cannabis during pregnancy and breastfeeding due to the risks of adverse maternal, fetal, and neonatal outcomes.