Boys exposed to cannabis before birth showed language and cognitive delays at age three | Research

The takeaway

In a matched case-control study, prenatal cannabis exposure was associated with lower cognitive and motor scores at age three, with the most severe delays in language development among boys.

Pediatric developmental specialists, obstetricians, early intervention providers, and prenatal health researchers

Two cannabis-exposed infants had severe developmental delay (score <70)

What the researchers found

Among 32 prenatally exposed and 32 matched control infants assessed at 36 months using the Bayley Scales, exposed infants scored significantly lower in cognitive, motor, and language domains. Cannabis-exposed infants specifically had lower cognitive and motor scores, and the most common and severe delays were in language, particularly among males.

Why it matters

Identifying specific developmental domains affected by prenatal cannabis exposure at age three can help guide early intervention strategies during a critical window for language and cognitive development.

The numbers in context

32 exposed infants (16 cannabis, 8 alcohol, 2 cocaine, 6 polysubstance) vs 32 controls; normal scores (>=85) in 23 exposed vs 29 controls; two cannabis-exposed infants had severe delay (score <70); male infants exposed to cannabis had significantly lower cognitive scores

How the study worked

Prospective matched case-control study using meconium biomarkers to confirm fetal substance exposure. The Bayley Scales of Infant and Toddler Development (BSID-III) were administered at 36 months to 32 exposed and 32 non-exposed infants.

What this study cannot tell us

Small sample size (only 16 cannabis-exposed); cannot fully separate cannabis effects from other substance exposures or socioeconomic factors; meconium only captures exposure in later pregnancy; single assessment time point

How to read the evidence

Small prospective case-control study with biomarker-confirmed exposure and validated developmental assessment, but limited by sample size.

When this study was published

2024 study with assessments at 36 months of age

The bigger picture

The sex-specific vulnerability of male infants to prenatal cannabis exposure adds to growing evidence that cannabis effects on fetal development are not uniform and may interact with biological sex.

Questions still open

Why are male infants more vulnerable to language delays from prenatal cannabis exposure? Would these developmental differences persist or resolve with age? Could early intervention close the gap?

Common questions

What developmental areas were affected by prenatal cannabis exposure?

Infants exposed to cannabis before birth scored significantly lower in cognitive and motor domains on the Bayley Scales at age three. The most common and severe delays were in language development, particularly among male infants.

Were all exposed children delayed?

No. Most exposed children (23 of 32) had scores in the normal range across all domains. However, compared to matched controls (where 29 of 32 scored normally), exposed children were more likely to show delays, and two cannabis-exposed children had severe developmental delay.

Read the original research

Evaluation of three-year neurodevelopmental outcomes in infants prenatally exposed to substance use.

Drug and alcohol dependence, 259, 111284

View on PubMed ↗Publisher’s paper ↗

Citation

Jarque, Pilar; Carmona, Miguel; Roca, Antonia; Barcelo, Bernardino; Pichini, Simona; Elorza, Miguel Ángel; Sanchis, Pilar; Rendal, Yolanda; Gomila, Isabel. (2024). Evaluation of three-year neurodevelopmental outcomes in infants prenatally exposed to substance use.. Drug and alcohol dependence, 259, 111284. https://doi.org/10.1016/j.drugalcdep.2024.111284