Children Exposed to Cannabis Before Birth Had Fewer Doctor Visits But More ER and Psychiatrist Visits | Research

The takeaway

Among over 500,000 Ontario children, those prenatally exposed to cannabis had 14% fewer primary care visits but 29% more psychiatrist visits and 12% more hospitalizations through age 10.

Pediatricians, prenatal care providers, public health planners, maternal health researchers.

29% more psychiatrist visits for exposed children

What the researchers found

In a retrospective cohort of 508,025 Ontario infants (3,248 cannabis-exposed), prenatal cannabis exposure was associated with 14% fewer primary care visits (aRR 0.86, 95% CI 0.84-0.87), 29% more outpatient psychiatrist visits (aRR 1.29, 95% CI 1.00-1.66), 5% more ER visits (aRR 1.05, 95% CI 1.03-1.08), and 12% more hospitalizations (aRR 1.12, 95% CI 1.04-1.20). Among the highest income quintile, cannabis exposure was associated with a twofold increase in psychiatrist visits.

Why it matters

This massive population-based study reveals a concerning pattern: children exposed to cannabis before birth visit primary care doctors less often but end up in emergency departments, hospitals, and psychiatrist offices more frequently. The reduced primary care suggests these families may face access barriers that lead to more acute healthcare needs.

The numbers in context

508,025 infants total. 3,248 (0.6%) cannabis-exposed. Primary care: aRR 0.86 (fewer). Psychiatrist: aRR 1.29 (more). ER: aRR 1.05 (more). Hospitalizations: aRR 1.12 (more). Follow-up to age 10.

How the study worked

Retrospective cohort using linked perinatal and health administrative databases for all live singleton births in Ontario hospitals (April 2007-March 2012). Infants followed until March 2017 (up to age 10). Cannabis exposure identified from maternal self-report. Adjusted Poisson regression assessed differences in healthcare utilization rates.

What this study cannot tell us

Self-reported cannabis use (0.6% prevalence) likely underestimates true exposure. Cannot separate cannabis effects from confounding socioeconomic factors that drive both cannabis use and healthcare patterns. Administrative data lacks clinical detail. Cannot determine whether children's health problems were caused by cannabis exposure or related social determinants.

How to read the evidence

Strong: massive population-based cohort (N=508,025) with linked administrative data and long follow-up, though self-reported exposure and inability to control for all confounders limit causal inference.

When this study was published

2025 study (data from 2007-2017)

The bigger picture

The pattern of less preventive care and more acute care is a well-known marker of healthcare access disparities. While prenatal cannabis exposure may contribute to child health problems, the reduced primary care visits suggest socioeconomic and access factors play a significant role in the healthcare utilization differences observed.

Questions still open

Are the increased ER and psychiatrist visits driven by cannabis exposure effects on child development, or by the social circumstances of families where cannabis is used during pregnancy? Would biomarker-confirmed exposure show stronger associations?

Common questions

Do children exposed to cannabis before birth need more medical care?

They used fewer routine doctor visits but had more emergency, hospital, and psychiatrist visits through age 10. However, these patterns may partly reflect socioeconomic differences in families rather than direct effects of cannabis exposure.

Why did exposed children see fewer primary care doctors?

The study could not determine the reason, but reduced primary care access is a common pattern in populations facing socioeconomic barriers, which are also associated with substance use during pregnancy.

Read the original research

Association Between Prenatal Cannabis Exposure and Child Health Care Use: A Retrospective Cohort Study in Ontario, Canada.

Journal of pediatrics. Clinical practice, 17, 200151

View on PubMed ↗Publisher’s paper ↗

Citation

Pratt Tremblay, Gabrielle; Han, Arum; Sucha, Ewa; Hsu, Helen; Donelle, Jessy; Corsi, Daniel J. (2025). Association Between Prenatal Cannabis Exposure and Child Health Care Use: A Retrospective Cohort Study in Ontario, Canada.. Journal of pediatrics. Clinical practice, 17, 200151. https://doi.org/10.1016/j.jpedcp.2025.200151