Large study found no link between prenatal cannabis use and child developmental delays
In a cohort of nearly 120,000 pregnancies, maternal cannabis use in early pregnancy was not associated with increased risk of speech/language disorders, motor delays, or global developmental delays in children through age 5.5 years.
Quick Facts
What This Study Found
No association was observed between maternal prenatal cannabis use and child speech/language disorders (HR 0.93, 95% CI 0.84-1.03), global developmental delays (HR 1.04, 95% CI 0.68-1.59), or motor delays (HR 0.86, 95% CI 0.69-1.06). No dose-response relationship was found.
Key Numbers
119,976 pregnancies among 106,240 individuals. 6,778 (5.6%) had documented cannabis use. Daily use: 618 (0.5%). Weekly: 722 (0.6%). Monthly or less: 1,617 (1.3%). No significant associations at any frequency.
How They Did This
Retrospective cohort of 119,976 children born 2015-2019 at Kaiser Permanente Northern California, followed to age 5.5 years. Prenatal cannabis use screened via self-report and urine toxicology at ~8-10 weeks gestation. Developmental delays identified from ICD-9/10 codes in electronic health records.
Why This Research Matters
While prenatal cannabis has been linked to neonatal outcomes like low birth weight, evidence on longer-term developmental effects has been limited and conflicting. This large study found no association with early developmental delays.
The Bigger Picture
This null finding contrasts with studies linking prenatal cannabis to ASD or ADHD, suggesting different developmental outcomes may have different risk profiles. The authors note this does not mean prenatal cannabis is safe, given known associations with other adverse outcomes.
What This Study Doesn't Tell Us
Cannabis use assessed only at entry to prenatal care (~8-10 weeks), missing later-pregnancy use patterns. Some developmental delays may not manifest until after age 5.5. Self-report likely underestimates use. EHR diagnosis codes may miss milder delays.
Questions This Raises
- ?Would longer follow-up (through school age) reveal associations not apparent by age 5.5?
- ?Do specific developmental domains show effects at later ages?
Trust & Context
- Key Stat:
- No association at any use frequency
- Evidence Grade:
- Large population-based cohort with objective screening and EHR follow-up provides strong evidence, though limited to early-pregnancy exposure assessment.
- Study Age:
- 2024 study of Kaiser Permanente data from 2015-2021
- Original Title:
- Early Maternal Prenatal Cannabis Use and Child Developmental Delays.
- Published In:
- JAMA network open, 7(10), e2440295 (2024)
- Authors:
- Avalos, Lyndsay A(13), Oberman, Nina(5), Alexeeff, Stacey E(19), Croen, Lisa A, Davignon, Meghan N, Adams, Sara R, Ansley, Deborah, Chambers, Christina D, Steuerle, Kristin, Young-Wolff, Kelly C
- Database ID:
- RTHC-05098
Evidence Hierarchy
Frequently Asked Questions
Does this mean cannabis is safe during pregnancy?
No. The authors emphasize that prenatal cannabis is associated with other adverse outcomes (low birth weight, preterm birth). This study only examined early developmental delays and found no link, but other risks remain.
How was cannabis use measured?
Through self-report and urine toxicology testing at entry to prenatal care (around 8-10 weeks gestation). This captures early pregnancy use but may miss use later in pregnancy.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-05098APA
Avalos, Lyndsay A; Oberman, Nina; Alexeeff, Stacey E; Croen, Lisa A; Davignon, Meghan N; Adams, Sara R; Ansley, Deborah; Chambers, Christina D; Steuerle, Kristin; Young-Wolff, Kelly C. (2024). Early Maternal Prenatal Cannabis Use and Child Developmental Delays.. JAMA network open, 7(10), e2440295. https://doi.org/10.1001/jamanetworkopen.2024.40295
MLA
Avalos, Lyndsay A, et al. "Early Maternal Prenatal Cannabis Use and Child Developmental Delays.." JAMA network open, 2024. https://doi.org/10.1001/jamanetworkopen.2024.40295
RethinkTHC
RethinkTHC Research Database. "Early Maternal Prenatal Cannabis Use and Child Developmental..." RTHC-05098. Retrieved from https://rethinkthc.com/research/avalos-2024-early-maternal-prenatal-cannabis
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.