Children exposed to marijuana before birth showed more behavioral problems by age 3.5 | Research

The takeaway

In a prospective cohort study, children exposed to marijuana during pregnancy showed more sleep problems, withdrawal symptoms, externalizing behaviors, and aggressive/oppositional behaviors at age 3.5, but no differences in executive functioning.

Pregnant individuals considering cannabis use, obstetricians, pediatricians, and prenatal health researchers.

More sleep problems, aggression, and oppositional behavior at age 3.5 with prenatal exposure

What the researchers found

Compared to non-exposed children, those with prenatal marijuana exposure had significantly more sleep-related problems, withdrawal symptoms, externalizing problems including aggressive behaviors and oppositional defiant behaviors at age 3.5. Executive functioning did not differ between groups.

Why it matters

Today's marijuana is significantly more potent than in previous decades, making earlier studies on prenatal exposure potentially less relevant. This cohort was exposed to contemporary, higher-potency marijuana, providing more current data on early childhood outcomes.

The numbers in context

63 children assessed at age 3.5; prenatal exposure from self-report + medical chart + urine toxicology; significant differences in sleep, withdrawal, externalizing, aggression, and oppositional behaviors; no differences in executive function

How the study worked

Prospective prenatal cohort in Columbus, Ohio. Prenatal marijuana exposure was determined from maternal self-report, medical chart abstraction, and urine toxicology. At age 3.5, 63 children completed tasks assessing executive function, visual-spatial ability, emotion regulation, and aggressive behavior. Caregivers reported on behavior.

What this study cannot tell us

Small sample of 63 children. Cannot fully control for other prenatal exposures and socioeconomic factors that correlate with marijuana use. Self-reported exposure may underestimate actual use. Single assessment at 3.5 years.

How to read the evidence

Prospective design with multiple exposure verification methods, but small sample and potential confounding.

When this study was published

Published in 2021.

The bigger picture

The finding that behavioral problems are detectable by age 3.5 but cognitive differences are not suggests prenatal marijuana exposure may affect emotional regulation and behavior before measurably affecting cognitive development.

Questions still open

Will executive function differences emerge at older ages? Are these behavioral effects permanent or transient? Does the dose and timing of prenatal exposure affect outcomes? How does prenatal marijuana exposure interact with postnatal environment?

Common questions

Does prenatal marijuana exposure affect children's behavior?

This study found children exposed before birth had more sleep problems, withdrawal symptoms, and aggressive/oppositional behaviors at age 3.5, though executive functioning was not affected.

Is today's marijuana more concerning during pregnancy?

The researchers note that today's marijuana is significantly more potent than what was studied in earlier decades, making these findings on contemporary exposures particularly relevant.

Read the original research

Behavioral and Cognitive Differences in Early Childhood related to Prenatal Marijuana Exposure.

Journal of applied developmental psychology, 77

View on PubMed ↗Publisher’s paper ↗

Citation

Murnan, Aaron W; Keim, Sarah A; Yeates, Keith Owen; Boone, Kelly M; Sheppard, Kelly W; Klebanoff, Mark A. (2021). Behavioral and Cognitive Differences in Early Childhood related to Prenatal Marijuana Exposure.. Journal of applied developmental psychology, 77. https://doi.org/10.1016/j.appdev.2021.101348