What research shows about cannabis exposure during pregnancy and its effects on mothers, babies, and child development | Research

The takeaway

Gestational cannabis exposure has been associated with impaired placental blood flow, smaller birth size, and potential longer-term neurodevelopmental and metabolic risks, though definitive evidence is still limited.

Pregnant women or those planning pregnancy, healthcare providers advising pregnant patients, researchers studying prenatal substance exposure

Associated with increased risk of small-for-gestational-age births

What the researchers found

Cannabis use during pregnancy has been associated with increased risk of other substance use, impaired placental blood flow, small-for-gestational-age births, and potential childhood outcomes including increased risk of depression and ADHD. Maternal metabolic effects may include fatty liver, obesity, and gestational diabetes.

Why it matters

With cannabis legalization expanding and THC potency increasing, more pregnant women may use cannabis. Understanding the full range of potential risks is critical for informed decision-making.

The numbers in context

THC potency has progressively increased over several decades; endometriosis affects approximately 10% of women (context for pain-driven use during pregnancy)

How the study worked

Narrative review examining epidemiological and clinical evidence on cannabis exposure during pregnancy and lactation, including effects on pregnancy outcomes, placental health, and child development.

What this study cannot tell us

Much of the evidence is observational and cannot establish causation. Confounding factors (tobacco, alcohol, socioeconomic status) are difficult to fully control. Childhood and adolescent outcomes are sparsely assessed.

How to read the evidence

Narrative review drawing on observational studies with significant confounding factors

When this study was published

Published in 2021. THC potency and cannabis formulations continue to change, potentially affecting prenatal exposure risks.

The bigger picture

As cannabis becomes more accessible and socially acceptable, the gap between its widespread use and the limited evidence about prenatal exposure risks becomes increasingly concerning for public health.

Questions still open

Does CBD-only use during pregnancy carry the same risks as THC-containing products? How does increasing THC potency affect fetal exposure levels? What are the long-term cardiometabolic outcomes for children exposed in utero?

Common questions

Is cannabis use during pregnancy safe?

Research has associated gestational cannabis exposure with several risks including impaired placental blood flow and smaller birth size, though definitive causal evidence is lacking due to the observational nature of most studies.

Can cannabis during pregnancy affect child development?

Limited evidence suggests associations with increased risk of depression and ADHD in childhood, as well as potential metabolic effects. However, long-term outcomes remain sparsely studied.

Read the original research

Association between gestational cannabis exposure and maternal, perinatal, placental, and childhood outcomes.

Journal of developmental origins of health and disease, 12(5), 694-703

View on PubMed ↗Publisher’s paper ↗

Citation

Ayonrinde, Oyekoya T; Ayonrinde, Oyedeji A; Van Rooyen, Derrick; Tait, Robert; Dunn, Mikaela; Mehta, Shailender; White, Scott; Ayonrinde, Oyekunle K. (2021). Association between gestational cannabis exposure and maternal, perinatal, placental, and childhood outcomes.. Journal of developmental origins of health and disease, 12(5), 694-703. https://doi.org/10.1017/S2040174420001166