Babies exposed to cannabis late in pregnancy scored higher on language tests at 12 months | Research

The takeaway

In a cohort of 69 exposed and 138 unexposed infants, late prenatal cannabis exposure was unexpectedly associated with higher expressive and receptive language scores at 12 months of age.

Developmental researchers, pediatricians, and anyone following the prenatal cannabis exposure literature.

Late-exposed infants scored higher on language at 12 months (p=0.004)

What the researchers found

Late-exposed infants (2nd/3rd trimester) scored significantly higher on expressive and receptive language subscales at 12 months compared to unexposed infants. Early-exposed infants (1st trimester only) showed higher gross motor scores. No differences in visual reception.

Why it matters

This counterintuitive finding challenges the assumption that all prenatal cannabis effects are negative. However, the authors note these early scores may not predict long-term outcomes and could reflect altered neural connectivity patterns.

The numbers in context

69 exposed, 138 unexposed infants. Late exposure: higher expressive language (95% CI: 2.54-12.76, p=0.004) and receptive language (95% CI: 0.39-8.72, p=0.03). Early exposure: higher gross motor scores (95% CI: 1.75-13, p=0.01). Mean maternal age: 23.7 (early) and 22.8 (late) years.

How the study worked

Prospective cohort from the Safe Passage Study. 69 cannabis-exposed infants matched with 138 unexposed controls. Cognitive screening at 12 months using the Mullen Scale of Early Learning. Multiple linear regression adjusted for covariates.

What this study cannot tell us

Small sample size. Observational design with potential unmeasured confounders. Cannabis-using mothers differed demographically from controls. 12-month assessments are very early and may not predict later development. Co-use of tobacco was common in the exposed group.

How to read the evidence

Prospective cohort with matched controls, but small sample size and very early outcome assessment limit conclusions.

When this study was published

Published 2023.

The bigger picture

Some animal studies show prenatal cannabinoid exposure alters brain connectivity. Higher early language scores could reflect accelerated development that normalizes or reverses later, a pattern seen with some other prenatal exposures. Long-term follow-up is essential.

Questions still open

Do these elevated early scores persist, plateau, or reverse at later developmental stages? Are the findings explained by altered neural connectivity patterns that manifest differently over time?

Common questions

Does this mean cannabis is good for fetal brain development?

No. This unexpected finding of higher early language scores does not mean cannabis benefits brain development. Early developmental scores often do not predict long-term outcomes, and the authors suggest altered neural connectivity could manifest differently as children age. The study also had a small sample and potential confounders.

Why would exposed babies score higher?

The authors propose that prenatal cannabinoid exposure may alter brain connectivity in ways that temporarily accelerate certain developmental milestones. Preclinical studies show cannabinoids affect neural circuit formation. Whether this represents genuine advancement or atypical development that creates problems later requires long-term follow-up.

Read the original research

Prenatal cannabinoid exposure and early language development.

Frontiers in pediatrics, 11, 1290707

View on PubMed ↗Publisher’s paper ↗

Citation

Talavera-Barber, Maria M; Morehead, Evlyn; Ziegler, Katherine; Hockett, Christine; Elliott, Amy J. (2023). Prenatal cannabinoid exposure and early language development.. Frontiers in pediatrics, 11, 1290707. https://doi.org/10.3389/fped.2023.1290707