Is it safe for a pregnant individual to use cannabis?

Cannabis Use During Pregnancy: Clinical Recommendation

Pregnant individuals must completely abstain from cannabis use due to established risks of adverse pregnancy outcomes including low birth weight, preterm birth, placental abruption, and potential long-term neurodevelopmental harm to the fetus. 1, 2

Guideline-Based Recommendation

The American College of Obstetricians and Gynecologists (ACOG) explicitly recommends that people who are pregnant, trying to become pregnant, or breastfeeding abstain from using cannabis. 3, 1, 4 This recommendation is based on documented risks to both maternal and fetal health, not theoretical concerns.

Documented Maternal and Pregnancy Risks

Cannabis use during pregnancy is associated with multiple adverse outcomes:

Maternal Complications

• Gestational hypertension with small to moderately increased risk 2
• Placental abruption, a potentially life-threatening complication 1, 2
• Abnormal gestational weight gain (both excessive and insufficient) 2

Fetal and Neonatal Outcomes

• Low birth weight - cannabis smoking during pregnancy is definitively associated with reduced fetal growth 3, 2
• Preterm birth at multiple gestational age cutoffs (<36, <34, and <32 weeks) 2
• Small for gestational age infants 2
• NICU admission with increased frequency 2
• Fetal death with increased risk 2
• Dose-response relationship: Greater frequency of cannabis use correlates with higher risk of adverse outcomes 2

Long-Term Neurodevelopmental Effects

• Subtle but persistent neurobehavioral impairments including cognitive dysfunction and behavioral difficulties 3, 1
• Effects on fetal brain development through cannabinoid receptor activation, as THC readily crosses the placenta 5

Critical Context: Increasing Potency

The risk profile has intensified dramatically because THC concentrations have nearly doubled from 9% in 2008 to 17% in 2017, making modern cannabis products significantly more dangerous than those studied in earlier research. 1, 6 Most historical studies were conducted when potency was substantially lower, meaning current risks may be underestimated. 5

Breastfeeding Considerations

Cannabis use is contraindicated during breastfeeding due to potential adverse neonatal outcomes from cannabinoid exposure through breast milk. 3 Women with substance use disorders should be counseled that breastfeeding is not advised if there is concurrent use of illicit substances, including cannabis. 3

Common Clinical Pitfall: Medicinal Use Misconception

Many pregnant women use cannabis to self-treat nausea, vomiting, anxiety, depression, insomnia, and chronic pain, often unaware of pregnancy-related risks. 2, 7 Obstetrician-gynecologists should be discouraged from prescribing or suggesting marijuana for medicinal purposes during preconception, pregnancy, and lactation. 4 Alternative therapies with better pregnancy-specific safety data should be recommended instead. 4

Clinical Action Steps

Screening and Counseling

• Screen all pregnant patients for cannabis use at the first prenatal visit and throughout pregnancy 7
• Provide clear, non-judgmental education about established risks to pregnancy outcomes and fetal neurodevelopment 3, 1
• Dispel misleading claims about cannabis safety during pregnancy through evidence-based counseling 3

Management of Cannabis Users

• Strongly advise complete cessation based on ACOG recommendations and established risks 1
• Assess for polysubstance use, particularly tobacco (which definitively increases miscarriage risk) and other substances that may compound risks 1, 5
• Offer alternative evidence-based treatments for nausea, pain, anxiety, or other symptoms the patient is attempting to manage with cannabis 4

Special Populations

• Women aged 15-17 years have higher rates of cannabis use during pregnancy compared to non-pregnant peers (15.8% vs 13.0%), requiring targeted intervention 3
• Patients with medical or mental health conditions are more likely to use cannabis during pregnancy and need intensive counseling 2

Evidence Quality Note

While some older studies show inconsistent results, recent cohort studies and meta-analyses demonstrate clear associations between maternal cannabis use and adverse outcomes, even in women who do not use other substances during pregnancy. 2 The evidence is sufficient to support firm recommendations against use, particularly given the lack of any demonstrated benefit and the established potential for harm. 5, 4