Combined prenatal cannabis and nicotine use doubled the risk of infant death compared to either substance alone | Research

The takeaway

Among 3.1 million California pregnancies, combined cannabis and nicotine exposure was associated with 2.2x higher infant death risk, 1.9x higher rates of small-for-gestational-age, and 1.8x more preterm deliveries versus non-use.

People interested in prenatal substance exposure and pregnancy outcomes.

2.18x infant death risk with combined cannabis + nicotine exposure

What the researchers found

Cannabis or nicotine alone each increased risks of infant death (0.7% for both), small-for-gestational-age (14.3% and 13.7%), and preterm delivery (12.2% and 12.0%). Combined use showed additive or super-additive risks: infant death 1.2% (ARR 2.18), neonatal death 0.6% (ARR 1.76), SGA 18.0% (ARR 1.94), and preterm delivery 17.5% (ARR 1.83).

Why it matters

This is one of the largest studies ever to examine combined cannabis-nicotine prenatal exposure. The finding that risks are higher with co-use than either substance alone has immediate implications for prenatal counseling, especially as cannabis use in pregnancy rises.

The numbers in context

3,129,259 pregnancies. Cannabis: 23,007 (0.7%). Nicotine: 56,811 (1.8%). Both: 10,312 (0.3%). Combined use ARRs: infant death 2.18, neonatal death 1.76, SGA 1.94, preterm 1.83. Mean maternal age 29.3 years.

How the study worked

Population-based retrospective cohort using linked California hospital discharge and vital statistics data (2012-2019). 3,129,259 singleton pregnancies analyzed. Cannabis and nicotine exposure identified by ICD-9/10 codes. Multivariable Poisson regression for adjusted risk ratios.

What this study cannot tell us

ICD code-based exposure capture likely underestimates true prevalence. Cannot determine dose, frequency, or timing of use. Residual confounding from socioeconomic and health factors. Cannot establish biological causation from administrative data.

How to read the evidence

Very large population-based cohort with over 3 million pregnancies published in JAMA Network Open. Limited by administrative coding and inability to determine dose or causation.

When this study was published

Published in 2024 covering California data from 2012-2019.

The bigger picture

Cannabis and nicotine are the two most commonly used substances in pregnancy after alcohol. With cannabis legalization increasing co-use, understanding the combined risk is essential. This JAMA study provides the evidence base for targeted cessation interventions addressing both substances together.

Questions still open

Is the combined risk additive or truly synergistic at the biological level? Would dual cessation programs be more effective than substance-specific ones? Does the timing of combined exposure during pregnancy matter?

Common questions

Is using cannabis and nicotine together worse during pregnancy?

Yes. This study of over 3 million pregnancies found the combination was associated with roughly double the risk of infant death, small babies, and preterm delivery compared to non-use, and higher risk than either substance alone.

How common is combined use in pregnancy?

In this California population, 0.3% of pregnancies had both cannabis and nicotine diagnoses. However, since these are based on medical coding, the true prevalence is likely higher.

Read the original research

Risk of Adverse Neonatal Outcomes After Combined Prenatal Cannabis and Nicotine Exposure.

JAMA network open, 7(5), e2410151

View on PubMed ↗Publisher’s paper ↗

Citation

Crosland, B Adam; Garg, Bharti; Bandoli, Gretchen E; Mandelbaum, Ava D; Hayer, Sarena; Ryan, Kimberly S; Shorey-Kendrick, Lyndsey E; McEvoy, Cindy T; Spindel, Eliot R; Caughey, Aaron B; Lo, Jamie O. (2024). Risk of Adverse Neonatal Outcomes After Combined Prenatal Cannabis and Nicotine Exposure.. JAMA network open, 7(5), e2410151. https://doi.org/10.1001/jamanetworkopen.2024.10151