Is it safe for pregnant individuals to use cannabis?

Cannabis Use in Pregnancy: Complete Abstinence Required

Pregnant individuals must completely abstain from cannabis use due to established risks of adverse pregnancy outcomes, including low birth weight, fetal growth restriction, placental dysfunction, and long-term neurodevelopmental impairment in offspring. 1

Primary Recommendation

The American College of Obstetricians and Gynecologists definitively recommends that people who are pregnant, trying to become pregnant, or breastfeeding abstain from using cannabis. 2, 1 This recommendation is based on:

• Established association with low birth weight - Cannabis smoking during pregnancy is directly linked to reduced fetal growth 2
• Placental dysfunction and serious pregnancy complications - Cannabis exposure increases risks of placental insufficiency and restricted intrauterine growth 1, 3
• Neurodevelopmental harm - Fetal exposure causes impairments in cognitive function, behavioral difficulties, and altered brain structure in offspring 1, 3, 4

Mechanism of Fetal Harm

Cannabis crosses the placenta readily and affects fetal development through multiple pathways:

• Direct fetal exposure - Delta-9-tetrahydrocannabinol (THC) crosses the placenta, and cannabinoid receptors are present in fetal brain and placental tissue 5, 6
• Placental disruption - Cannabis impairs placental functioning, contributing to growth restriction and potential placental insufficiency 3, 7
• Brain development interference - Prenatal exposure causes structural and functional brain alterations, including changes in gray matter volume, cortical thickness, and prefrontal cortex connectivity 3, 4

Short-Term Pregnancy Risks

Cannabis use during pregnancy increases the following immediate complications:

• Preterm birth - Increased likelihood of premature delivery 3, 6
• Fetal growth restriction - Higher risk of small-for-gestational-age infants 5, 6, 7
• Low birth weight - Consistently documented across multiple studies 2, 5, 6

Long-Term Offspring Outcomes

Children exposed to cannabis in utero face persistent developmental challenges:

• Cognitive impairment - Decreased cognitive abilities and reduced academic performance 1, 3, 4
• Behavioral problems - Increased behavioral difficulties and sociobehavioral impairment 1, 3, 6
• Neuropsychiatric disease risk - Elevated risk for psychosis, depression, anxiety, and sleep disorders 4
• Metabolic dysregulation - Long-term increased risk for obesity, diabetes, and cardiovascular disease 7

Critical Considerations About Modern Cannabis

The risks are substantially higher with contemporary cannabis products:

• Dramatically increased potency - THC concentrations nearly doubled from 9% in 2008 to 17% in 2017, with some concentrates reaching 70% THC 1, 8
• Higher doses amplify all risks - More potent products intensify adverse effects on fetal development 8, 4
• Limited research on current potency levels - Most historical studies used lower-potency cannabis, meaning current risks may be underestimated 5, 4

Breastfeeding Prohibition

Cannabis use must also be avoided during lactation:

• THC detected in breast milk - The psychoactive component transfers to nursing infants 6
• Potential neurodevelopmental impact - Exposure during this critical period may affect infant brain development 6

Clinical Counseling Approach

When addressing cannabis use with pregnant patients:

• Screen all pregnant women for cannabis use, as self-reporting significantly underestimates actual prevalence (reported 3-35% range likely reflects underreporting) 4
• Provide clear, unequivocal guidance that cannabis is not safe during pregnancy, countering misleading claims about safety 2
• Address nausea management with evidence-based alternatives, as cannabis use for pregnancy-related nausea poses documented fetal risks 4
• Screen for depression and anxiety that may drive self-medication with cannabis, and offer appropriate psychiatric treatment 4
• Emphasize preconception cessation for women trying to conceive, as early pregnancy exposure affects embryo implantation and development 1, 6

Common Pitfalls to Avoid

• Do not accept "natural" or "medicinal" justifications - Despite legalization trends and perceptions of safety, cannabis poses documented fetal risks 4, 6
• Do not minimize early exposure - Even brief or early pregnancy cannabis use is associated with fetal growth restriction and altered developmental trajectories 7
• Do not overlook polysubstance use - Cannabis users often use tobacco concurrently, which compounds miscarriage risk and other adverse outcomes 1