What topics does this cannabis study cover?

This study covers research on: Pain.

Where was this research published?

Published in Paediatric and perinatal epidemiology on September 6, 2026.

Early pregnancy cannabis use linked to higher preterm birth risk

Q: What did this research study find?

Female cannabis use **at least once per week during early pregnancy was associated with a higher incidence of *preterm birth***, although the estimate was imprecise.

A Prospective Study of Preconception and Early Pregnancy Cannabis Use and Birth Outcomes.

Paediatric and perinatal epidemiology • September 6, 2026 • Highly Relevant

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AI Summary

This prospective study followed 6,838 couples who were trying to conceive in the United States or Canada. Researchers examined cannabis use by both partners before conception and by female participants during early pregnancy, then assessed preterm birth (PTB), small-for-gestational-age (SGA), and large-for-gestational-age (LGA) birth outcomes.

Cannabis use before conception was not appreciably associated with PTB for either partner. However, more frequent female cannabis use during early pregnancy was associated with a higher incidence of PTB: use at least once per week was linked with a hazard ratio of 1.87 compared with non-use, although the results were described as imprecise. Cannabis use was not associated with SGA or LGA. For people who are pregnant or planning pregnancy, the findings support avoiding cannabis during early pregnancy, while also indicating that preconception use requires further study.

💡 Key Findings

Female cannabis use at least once per week during early pregnancy was associated with a higher incidence of preterm birth, although the estimate was imprecise.

Good

78%

Preconception cannabis use by either female or male partners was not appreciably associated with preterm birth in this study.

Good

75%

Cannabis use by either partner was not associated with small-for-gestational-age or large-for-gestational-age birth.

Good

75%

The findings support existing evidence that cannabis use during early pregnancy may be a risk factor for preterm birth.

High

80%

📄 Original Abstract

Cannabis use among reproductive-aged individuals is common, yet there are gaps in our understanding of the effect of cannabis use on adverse birth outcomes. To determine the extent to which female and male preconception cannabis use and female early pregnancy cannabis use are associated with the incidence of preterm birth (PTB), small-for-gestational-age birth (SGA), and large-for-gestational-age (LGA) birth. We analysed data from Pregnancy Study Online, an internet-based preconception cohort study of couples trying to conceive. Eligible participants were aged 21-45 years (female) and ≥ 21 years (male) and residents of the United States or Canada. We followed 6838 couples who conceived between June 2013 and September 2024. Both partners completed preconception baseline questionnaires; female participants completed preconception follow-up questionnaires every 8 weeks, at early (< 12 weeks) and late pregnancy (~32 weeks), and at 6 months postpartum. Participants self-reported cannabis use during preconception (female and male) and early pregnancy (female only). We ascertained birthweight and gestational age from birth certificates and questionnaires and defined PTB (delivery < 37 gestational weeks) and SGA and LGA (< 10th and > 90th percentiles of birthweight, respectively, for gestational age and sex). We fit Cox regression models to estimate hazard ratios (HR) and 95% confidence intervals (CI), adjusting for potential confounders. Preconception cannabis use was not appreciably associated with PTB (≥ 1 per week vs. non-use: HR 1.06, 95% CI 0.71, 1.57 for females and HR 1.41, 95% CI 0.73, 2.75 for males). Higher frequency of female cannabis use in early pregnancy was associated with an increased incidence of PTB, although results were imprecise (≥ 1 per week vs. non-use: HR 1.87, 95% CI 1.06, 3.29; < 1/week vs. non-use: HR 0.85, 95% CI 0.36, 2.02). Cannabis use in either partner was not associated with the incidence of SGA or LGA. Our results support the existing evidence that cannabis use during early pregnancy is a risk factor for PTB.

Paper Type

📄 Research

Publication

Journal: Paediatric and perinatal epidemiology
Published: September 6, 2026
PMID: 42703005
DOI: 10.1111/ppe.70201

Authors (9)

Amelia K Wesselink Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA.
Ruth J Geller Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA.
Alyssa F Harlow Department of Population and Public Health Sciences, University of Southern California Keck School of Medicine, Los Angeles, California, USA.
Collette N Ncube Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA.
Krystal E Kuan Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA.
+4 more authors